MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS

[Title 24 CFR 3280]
[Code of Federal Regulations (annual edition) - May 1, 2001 Edition]
[Title 24 - HOUSING AND URBAN DEVELOPMENT]
[Subtitle B - Regulations Relating to Housing and Urban Development]
[Chapter Xx - OFFICE OF ASSISTANT SECRETARY FOR HOUSING--FEDERAL HOUSING]
[Part 3280 - MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS]
[From the U.S. Government Printing Office]

24HOUSING AND URBAN DEVELOPMENT52001-05-012001-05-01falseMANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS3280PART 3280HOUSING AND URBAN DEVELOPMENTRegulations Relating to Housing and Urban DevelopmentOFFICE OF ASSISTANT SECRETARY FOR HOUSING--FEDERAL HOUSING
PART 3280--MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS--Table of Contents

Subpart A--General

Sec.
3280.1 Scope.
3280.2 Definitions.
3280.3 Manufactured home procedural and enforcement regulations and
consumer manual requirements.
3280.4 Incorporation by reference.
3280.5 Data plate.
3280.6 Serial number.
3280.7 Excluded structures.
3280.8 Waivers.
3280.9 Interpretative bulletins.
3280.10 Use of alternative construction.
3280.11 Certification label.

Subpart B--Planning Considerations

3280.101 Scope.
3280.102 Definitions.
3280.103 Light and ventilation.
3280.104 Ceiling heights.
3280.105 Exit facilities; exterior doors.
3280.106 Exit facilities; egress windows and devices.
3280.107 Interior privacy.
3280.108 Interior passage.
3280.109 Room requirements.
3280.110 Minimum room dimensions.
3280.111 Toilet compartments.
3280.112 Hallways.
3280.113 Glass and glazed openings.

Subpart C--Fire Safety

3280.201 Scope.
3280.202 Definitions.
3280.203 Flame spread limitations and fire protection requirements.
3280.204 Kitchen cabinet protection.
3280.205 Carpeting.
3280.206 Firestopping.
3280.207 Requirements for foam plastic thermal insulating materials.
3280.208 Fire detection equipment.
3280.209 Fire testing.

Subpart D--Body and Frame Construction Requirements

3280.301 Scope.
3280.302 Definitions.
3280.303 General requirements.
3280.304 Materials.
3280.305 Structural design requirements.
3280.306 Windstorm protection.
3280.307 Resistance to elements and use.
3280.308 Formaldehyde emission controls for certain wood products.
3280.309 Health Notice on formaldehyde emissions.

Subpart E--Testing

3280.401 Structural load tests.
3280.402 Test procedure for roof trusses.
3280.403 Standard for windows and sliding glass doors used in
manufactured homes.
3280.404 Standard for egress windows and devices for use in
manufactured homes.
3280.405 Standard for swinging exterior passage doors for use in
manufactured homes.
3280.406 Air chamber test method for certification and qualification of
formaldehyde emission levels.

Subpart F--Thermal Protection

3280.501 Scope.
3280.502 Definitions.
3280.503 Materials.
3280.504 Condensation control and installation of vapor retarders.
3280.505 Air infiltration.
3280.506 Heat loss/heat gain.
3280.507 Comfort heat gain.
3280.508 Heat loss, heat gain and cooling load calculations.
3280.509 Criteria in absence of specific data.
3280.510 Heat loss certificate.
3280.511 Comfort cooling certificate and information.

Subpart G--Plumbing Systems

3280.601 Scope.
3280.602 Definitions.
3280.603 General requirements.
3280.604 Materials.
3280.605 Joints and connections.
3280.606 Traps and cleanouts.
3280.607 Plumbing fixtures.
3280.608 Hangers and supports.
3280.609 Water distribution systems.
3280.610 Drainage systems.
3280.611 Vents and venting.
3280.612 Tests and inspection.

Subpart H--Heating, Cooling and Fuel Burning Systems

3280.701 Scope.
3280.702 Definitions.
3280.703 Minimum standards.
3280.704 Fuel supply systems.
3280.705 Gas piping systems.
3280.706 Oil piping systems.
3280.707 Heat producing appliances.
3280.708 Exhaust duct system and provisions for the future installation
of a clothes dryer.
3280.709 Installation of appliances.
3280.710 Venting, ventilation and combustion air.
3280.711 Instructions.
3280.712 Marking.
3280.713 Accessibility.
3280.714 Appliances, cooling.
3280.715 Circulating air systems.

[[Page 108]]

Subpart I--Electrical Systems

3280.801 Scope.
3280.802 Definitions.
3280.803 Power supply.
3280.804 Disconnecting means and branch-circuit protective equipment.
3280.805 Branch circuits required.
3280.806 Receptacle outlets.
3280.807 Fixtures and appliances.
3280.808 Wiring methods and materials.
3280.809 Grounding.
3280.810 Electrical testing.
3280.811 Calculations.
3280.812 Wiring of expandable units and dual units.
3280.813 Outdoor outlets, fixtures, air conditioning equipment, etc.
3280.814 Painting of wiring.
3280.815 Polarization.
3280.816 Examination of equipment for safety.

Subpart J--Transportation

3280.901 Scope.
3280.902 Definitions.
3280.903 General requirements for designing the structure to withstand
transportation shock and vibration.
3280.904 Specific requirements for designing the transportation system.

Authority: 42 U.S.C. 3535(d), 5403, and 5424.

Source: 40 FR 58752, Dec. 18, 1975, unless otherwise noted.
Redesignated at 44 FR 20679, Apr. 6, 1979.

Subpart A--General

Sec. 3280.1 Scope.

This standard covers all equipment and installations in the design,
construction, transportation, fire safety, plumbing, heat-producing and
electrical systems of manufactured homes which are designed to be used
as dwelling units. This standard seeks to the maximum extent possible to
establish performance requirements. In certain instances, however, the
use of specific requirements is necessary.

[58 FR 55002, Oct. 25, 1993]

Sec. 3280.2 Definitions.

Definitions in this subpart are those common to all subparts of the
standard and are in addition to the definitions provided in individual
parts. The definitions are as follows:
Approved, when used in connection with any material, appliance or
construction, means complying with the requirements of the Department of
Housing and Urban Development.
Bay window--a window assembly whose maximum horizontal projection is
not more than two feet from the plane of an exterior wall and is
elevated above the floor level of the home.
Certification label means the approved form of certification by the
manufacturer that, under Sec. 3280.8, is permanently affixed to each
transportable section of each manufactured home manufactured for sale in
the United States.
Dwelling unit means one or more habitable rooms which are designed
to be occupied by one family with facilities for living, sleeping,
cooking and eating.
Equipment includes materials, appliances, devices, fixtures,
fittings or accessories both in the construction of, and in the fire
safety, plumbing, heat-producing and electrical systems of manufactured
homes.
Federal manufactured home construction and safety standard means a
reasonable standard for the construction, design, and performance of a
manufactured home which meets the needs of the public including the need
for quality, durability, and safety.
Installations means all arrangements and methods of construction, as
well as fire safety, plumbing, heat-producing and electrical systems
used in manufactured homes.
Labeled means a label, symbol or other identifying mark of a
nationally recognized testing laboratory, inspection agency, or other
organization concerned with product evaluation that maintains periodic
inspection of production of labeled equipment or materials, and by whose
labeling is indicated compliance with nationally recognized standards or
tests to determine suitable usage in a specified manner.
Length of a manufactured home means its largest overall length in
the traveling mode, including cabinets and other projections which
contain interior space. Length does not include bay windows, roof
projections, overhangs, or eaves under which there is no interior space,
nor does it include drawbars, couplings or hitches.

[[Page 109]]

Listed or certified means included in a list published by a
nationally recognized testing laboratory, inspection agency, or other
organization concerned with product evaluation that maintains periodic
inspection of production of listed equipment or materials, and whose
listing states either that the equipment or material meets nationally
recognized standards or has been tested and found suitable for use in a
specified manner.
Manufacturer means any person engaged in manufacturing or assembling
manufactured homes, including any person engaged in importing
manufactured homes for resale.
Manufactured home means a structure, transportable in one or more
sections, which in the traveling mode, is eight body feet or more in
width or forty body feet or more in length, or, when erected on site, is
three hundred twenty or more square feet, and which is built on a
permanent chassis and designed to be used as a dwelling with or without
a permanent foundation when connected to the required utilities, and
includes the plumbing, heating, air-conditioning, and electrical systems
contained therein. Calculations used to determine the number of square
feet in a structure will be based on the structure's exterior dimensions
measured at the largest horizontal projections when erected on site.
These dimensions will include all expandable rooms, cabinets, and other
projections containing interior space, but do not include bay windows.
This term includes all structures which meet the above requirements
except the size requirements and with respect to which the manufacturer
voluntarily files a certification pursuant to Sec. 3282.13 and complies
with the standards set forth in part 3280. Nothing in this subsection
should be interpreted to mean that a manufactured home necessarily meets
the requirements of HUD's Minimum Property Standards (HUD Handbook
4900.1) or that it is automatically eligible for financing under 12
U.S.C. 1709(b).
Manufactured home construction means all activities relating to the
assembly and manufacture of a manufactured home including, but not
limited to, those relating to durability, quality and safety.
Manufactured home safety means the performance of a manufactured
home in such a manner that the public is protected against any
unreasonable risk of the occurrence of accidents due to the design or
construction of such manufactured home, or any unreasonable risk of
death or injury to the user or to the public if such accidents do occur.
Registered Engineer or Architect means a person licensed to practice
engineering or architecture in a state and subject to all laws and
limitations imposed by the state's Board of Engineering and Architecture
Examiners and who is engaged in the professional practice of rendering
service or creative work requiring education, training and experience in
engineering sciences and the application of special knowledge of the
mathematical, physical and engineering sciences in such professional or
creative work as consultation, investigation, evaluation, planning or
design and supervision of construction for the purpose of securing
compliance with specifications and design for any such work.
Secretary means the Secretary of Housing and Urban Development, or
an official of the Department delegated the authority of the Secretary
with respect to title VI of Pub. L. 93-383.
State includes each of the several States, the District of Columbia,
the Commonwealth of Puerto Rico, Guam, the Virgin Islands, the Canal
Zone, and American Samoa.
Width of a manufactured home means its largest overall width in the
traveling mode, including cabinets and other projections which contain
interior space. Width does not include bay windows, roof projections,
overhangs, or eaves under which there is no interior space.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 960, Jan. 4, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 47 FR 28092,
June 29, 1982; 58 FR 55002, Oct. 25, 1993; 61 FR 5216, Feb. 9, 1996]

[[Page 110]]

Sec. 3280.3 Manufactured home procedural and enforcement regulations and consumer manual requirements.

A manufacturer must comply with the requirements of this part 3280,
part 3282 of this chapter, and 42 U.S.C. 5416.

[61 FR 18250, Apr. 25, 1996]

Sec. 3280.4 Incorporation by reference.

(a) The specifications, standards and codes of the following
organizations are incorporated by reference in 24 CFR part 3280 (this
Standard) pursuant to 5 U.S.C. 552(a) and 1 CFR part 51 as though set
forth in full. The incorporation by reference of these standards has
been approved by the Director of the Federal Register. Reference
standards have the same force and effect as this Standard (24 CFR part
3280) except that whenever reference standards and this Standard are
inconsistent, the requirements of this Standard prevail to the extent of
the inconsistency.
(b) The abbreviations and addresses of organizations issuing the
referenced standards appear below. Reference standards which are not
available from their producer organizations may be obtained from the
Office of Manufactured Housing and Regulatory Functions, Manufactured
Housing and Construction Standards Division, U.S. Department of Housing
and Urban Development, 451 Seventh Street, SW., room B-133, Washington,
DC 20410.

AA--Aluminum Association, 900 19th Street NW., suite 300, Washington, DC
20006.
AAMA--American Architectural Manufacturers Association, 1540 East Dundee
Road, Palatine, Illinois 60067
AFPA [previously (N)FPA]--American Forest and Paper Association, 1250
Connecticut Avenue, NW., Washington, DC 20036 [previously named (N)FPA-
National Forest Products Association]
AGA--American Gas Association, 8501 East Pleasant Valley Road,
Cleveland, Ohio 44131
AISC--American Institute of Steel Construction, One East Wacker Drive,
Chicago, IL 60601
AISI--American Iron and Steel Institute, 1101 17th Street, NW.,
Washington, DC 20036
AITC--American Institute of Timber Construction, 11818 SE Mill Plain
Blvd., suite 415, Vancouver, Washington 98684
ANSI--American National Standards Institute, 1430 Broadway, New York,
New York 10018
APA--American Plywood Association, P.O. Box 11700, Tacoma, Washington
98411
ARI--Air Conditioning and Refrigeration Institute, 1501 Wilson Blvd.,
6th Floor, Arlington, VA 22209-2403
ASCE--American Society of Civil Engineers, 345 East 47th Street, New
York, New York 10017-2398
ASHRAE--American Society of Heating, Refrigeration and Air Conditioning
Engineers, 1791 Tulle Circle, NE., Atlanta, Georgia 30329
ASME--American Society of Mechanical Engineers, 345 East 47th Street,
New York, New York 10017
ASSE--American Society of Sanitary Engineering, P.O. Box 40362, Bay
Village, Ohio 44140
ASTM--American Society for Testing and Materials, 1916 Race Street,
Philadelphia, Pennsylvania 19103
CISPI--Cast Iron Soil Pipe Institute, 5959 Shallowford Road, suite 419,
Chattanooga, TN 37421
DOC--U.S. Department of Commerce, National Institute of Standards and
Technology, Office of Engineering Standards, room A-166, Technical
Building, Washington, DC 20234
FS--Federal Specifications, General Services Administration,
Specifications Branch, room 6039, GSA Building, 7th and D Streets, SW.,
Washington, DC 20407
HPVA (previously HPMA)--Hardwood Plywood and Veneer Association, P.O.
Box 2789, Reston, VA 22090 (previously named HPMA Hardwood Plywood
Manufacturers Association)
HUD-FHA--Department of Housing and Urban Development, 451 Seventh
Street, SW., Washington, DC 20410
HUD--USER Department of Housing and Urban Development, HUD User, P.O.
Box 280, Germantown, MD 20874
IAPMO--International Association of Plumbing and Mechanical Officials,
20001 Walnut Drive South, Walnut, CA 91784-2825
IITRI--IIT Research Institute, 10 West 35th Street, Chicago, IL 60616
MIL--Military Specifications and Standards, Naval Publications and Forms
Center, 5801 Tabor Avenue, Philadelphia, Pennsylvania 19120
NFPA--National Fire Protection Association, Batterymarch Park, Quincy,
MA 02269
NPA--National Particleboard Association, 18928 Premiere Court,
Gaithersburg, MD 20879
NSF--National Sanitation Foundation, P.O. Box 1468, Ann Arbor, MI 48105
NWWDA--National Wood Window and Door Association, 1400 E. Toughy Avenue,
suite G-54, Des Plaines, IL 60018
SAE--Society of Automotive Engineers, 400 Commonwealth Drive,
Warrendale, Pennsylvania 15096

[[Page 111]]

SJI--Steel Joist Institute, 1205 48th Avenue North, suite A, Myrtle
Beach, SC 29577
TPI--Truss Plate Institute, 583 D'Onofrio Drive, suite 200, Madison,
Wisconsin 53719
UL--Underwriters' Laboratories, Inc., 333 Pfingsten Road, Northbrook,
Illinois 60062

(c) The Department will enforce the listed editions of material
incorporated by reference into this standard. If a later edition is to
be enforced, the Department will publish a notice of change in the
Federal Register.

[47 FR 49385, Nov. 1, 1982, as amended at 52 FR 47553, Dec. 15, 1987; 58
FR 55002, Oct. 25, 1993; 59 FR 15113, Mar. 31, 1994]

Sec. 3280.5 Data plate.

Each manufactured home shall bear a data plate affixed in a
permanent manner near the main electrical panel or other readily
accessible and visible location. Each data plate shall be made of
material what will receive typed information as well as preprinted
information, and which can be cleaned of ordinary smudges or household
dirt without removing information contained on the data plate; or the
data plate shall be covered in a permanent manner with materials that
will make it possible to clean the data plate of ordinary dirt and
smudges without obscuring the information. Each data plate shall contain
not less than the following information:
(a) The name and address of the manufacturing plant in which the
manufactured home was manufactured.
(b) The serial number and model designation of the unit, and the
date the unit was manufactured.
(c) The statement:

This manufactured home is designed to comply with the Federal
Manufactured Home Construction and Safety Standards in force at the time
of manufacture.

(d) A list of the certification label(s) number(s) that are affixed
to each transportable manufactured section under Sec. 3280.8.
(e) A list of major factory-installed equipment, including the
manufacturer's name and the model designation of each appliance.
(f) Reference to the roof load zone and wind load zone for which the
home is designed and duplicates of the maps as set forth in
Sec. 3280.305(c). This information may be combined with the heating/
cooling certificate and insulation zone map required by Secs. 3280.510
and 3280.511. The Wind Zone Map on the Data Plate shall also contain the
statement:

This home has not been designed for the higher wind pressures and
anchoring provisions required for ocean/coastal areas and should not be
located within 1500' of the coastline in Wind Zones II and III, unless
the home and its anchoring and foundation system have been designed for
the increased requirements specified for Exposure D in ANSI/ASCE 7-88.

(g) The statement:

This home has--has not--(appropriate blank to be checked by
manufacturer) been equipped with storm shutters or other protective
coverings for windows and exterior door openings. For homes designed to
be located in Wind Zones II and III, which have not been provided with
shutters or equivalent covering devices, it is strongly recommended that
the home be made ready to be equipped with these devices in accordance
with the method recommended in the manufacturers printed instructions.

(h) The statement: ``Design Approval by'', followed by the name of
the agency that approved the design.

[59 FR 2469, Jan. 14, 1994]

Sec. 3280.6 Serial number.

(a) A manufactured home serial number which will identify the
manufacturer and the state in which the manufactured home is
manufactured, must be stamped into the foremost cross member. Letters
and numbers must be \3/8\ inch minimum in height. Numbers must not be
stamped into hitch assembly or drawbar.

Sec. 3280.7 Excluded structures.

Certain structures may be excluded from these Standards as modular
homes under 24 CFR 3282.12.

[52 FR 4581, Feb. 12, 1987]

Sec. 3280.8 Waivers.

(a) Where any material piece of equipment, or system which does not
meet precise requirements or specifications set out in the standard is
shown, to the satisfaction of the Secretary, to meet an equivalent level
of performance, the Secretary may waive the specifications set out in
the Standard

[[Page 112]]

for that material, piece of equipment, or system.
(b) Where the Secretary is considering issuing a waiver to a
Standard, the proposed waiver shall be published in the Federal Register
for public comment, unless the Secretary, for good cause, finds that
notice is impractical, unnecessary or contrary to the public interest,
and incorporates into the waiver that finding and a brief statement of
the reasons therefor.
(c) Each proposed and final waiver shall include:
(1) A statement of the nature of the waiver; and
(2) Identification of the particular standard affected.
(d) All waivers shall be published in the Federal Register and shall
state their effective date. Where a waiver has been issued, the
requirements of the Federal Standard to which the waiver relates may be
met either by meeting the specifications set out in the Standard or by
meeting the requirements of the waiver published in the Federal
Register.

[58 FR 55003, Oct. 25, 1993]

Sec. 3280.9 Interpretative bulletins.

Interpretative bulletins may be issued for the following purposes:
(a) To clarify the meaning of the Standard; and
(b) To assist in the enforcement of the Standard.

[58 FR 55003, Oct. 25, 1993]

Sec. 3280.10 Use of alternative construction.

Requests for alternative construction can be made pursuant to 24 CFR
3282.14 of this chapter.

[58 FR 55003, Oct. 25, 1993]

Sec. 3280.11 Certification label.

(a) A permanent label shall be affixed to each transportable section
of each manufactured home for sale or lease in the United States. This
label shall be separate and distinct from the data plate which the
manufacturer is required to provide under Sec. 3280.5 of the standards.
(b) The label shall be approximately 2 in. by 4 in. in size and
shall be permanently attached to the manufactured home by means of 4
blind rivets, drive screws, or other means that render it difficult to
remove without defacing it. It shall be etched on 0.32 in. thick
aluminum plate. The label number shall be etched or stamped with a 3
letter designation which identifies the production inspection primary
inspection agency and which the Secretary shall assign. Each label shall
be marked with a 6 digit number which the label supplier shall furnish.
The labels shall be stamped with numbers sequentially.
(c) The label shall read as follows:

As evidenced by this label No. ABC 000001, the manufacturer
certifies to the best of the manufacturer's knowledge and belief that
this manufactured home has been inspected in accordance with the
requirements of the Department of Housing and Urban Development and is
constructed in conformance with the Federal manufactured home
construction and safety standards in effect on the date of manufacture.
See date plate.

(d) The label shall be located at the tail-light end of each
transportable section of the manufactured home approximately one foot up
from the floor and one foot in from the road side, or as near that
location on a permanent part of the exterior of the manufactured home
unit as practicable. The road side is the right side of the manufactured
home when one views the manufactured home from the tow bar end of the
manufactured home.

[42 FR 960, Jan. 4, 1977. Redesignated at 44 FR 20679, Apr. 6, 1979, as
amended at 52 FR 47553, Dec. 15, 1987. Redesignated and amended at 58 FR
55003, Oct. 25, 1993]

Subpart B--Planning Considerations

Sec. 3280.101 Scope.

Subpart B states the planning requirements in manufactured homes.
The intent of this subpart is to assure the adequacy of architectural
planning considerations which assist in determining a safe and healthful
environment.

Sec. 3280.102 Definitions.

(a) Gross floor area means all space, wall to wall, including
recessed entries not to exceed 5 sq. ft. and areas under built-in
vanities and similar furniture. Where the ceiling height is less than

[[Page 113]]

that specified in Sec. 3280.104, the floor area under such ceilings
shall not be included. Floor area of closets shall not be included in
the gross floor area.
(b) Habitable room means a room or enclosed floor space arranged for
living, eating, food preparation, or sleeping purposes not including
bathrooms, foyers, hallways, and other accessory floor space.
(c) Laundry area means an area containing or designed to contain a
laundry tray, clothes washer and/or clothes dryer.

Sec. 3280.103 Light and ventilation.

(a) Lighting. Each habitable room shall be provided with exterior
windows and/or doors having a total glazed area of not less than 8
percent of the gross floor area.
(1) Kitchens, bathrooms, toilet compartments, laundry areas, and
utility rooms may be provided with artificial light in place of windows.
(2) Rooms and areas may be combined for the purpose of providing the
required natural lighting provided that at least one half of the common
wall area is open and unobstructed, and the open area is at least equal
to 10 percent of the combined floor area or 25 square feet whichever is
greater.
(b) Whole house ventilation. Each manufactured home shall be capable
of providing a minimum of 0.35 air changes per hour continuously or at
an equivalent hourly average rate. The following criteria shall be
adhered to.
(1) Natural infiltration and exfiltration shall be considered as
providing 0.25 air changes per hour.
(2) The remaining ventilation capacity of 0.10 air change per hour
or its hourly average equivalent shall be calculated using 0.035 cubic
feet per minute per square foot of interior floor space. This
ventilation capacity shall be in addition to any openable window area.
(3) The remaining ventilation capacity may be provided by: a
mechanical system, or a passive system, or a combination passive and
mechanical system. The ventilation system or provisions shall not create
a positive pressure in Uo value Zones 2 and 3 or a negative pressure
condition in Uo value Zone 1. Mechanical systems shall be balanced.
Combination passive and mechanical systems shall have adequately sized
inlets or exhaust to release any unbalanced pressure. Passive systems
shall have inlets and exhaust of sufficient size to alleviate unbalance
pressure conditions under normal conditions. Temporary imbalances due to
gusting or high winds are permitted.
(4) The ventilation system or provision shall exchange air directly
with the exterior of the home, except it shall not draw or expel air
with the space underneath the home. The ventilation system or provision
shall not draw or expel air into the floor, wall, or ceiling/roof
systems even if those systems are vented.
(5) The ventilation system or a portion thereof may be integral with
the homes heating or cooling system. The system shall be capable of
operating independently of the heating or cooling modes. A ventilation
system that is integral with the heating or cooling system shall be
listed as part of the heating and cooling system or listed as suitable
for use therewith.
(6) A mechanical ventilation system, or mechanical portion thereof,
shall be provided with a manual control and may be provided with
automatic timers or humidistats.
(7) Substantiation of the ventilation capacity to provide 0.10 ACH
shall be provided for a mechanical system, or a passive system, or a
combination passive and mechanical system.
(c) Additional ventilation. (1) At least half of the minimum
required glazed area in paragraph (a) of this section shall be openable
directly to the outside of the manufactured home for unobstructed
ventilation. These same ventilation requirements apply to rooms combined
in accordance with Sec. 3280.103(a)(2).
(2) Kitchens shall be provided with a mechanical ventilation system
that is capable of exhausting 100 cfm to the outside of the home. The
exhaust fan shall be located as close as possible to the range or cook
top, but in no case farther than 10 feet horizontally from the range or
cook top.
(3) Each bathroom and separate toilet compartment shall be provided
with a mechanical ventilation system capable of exhausting 50 cfm to the
outside

[[Page 114]]

of the home. A separate toilet compartment may be provided with 1.5
square feet of openable glazed area in place of mechanical ventilation,
except in Uo value Zone 3.

[58 FR 55003, Oct. 25, 1993]

Sec. 3280.104 Ceiling heights.

(a) Every habitable room and bathroom shall have a minimum ceiling
height of not less than 7 feet, 0 inches for a minimum of 50 percent of
the room's floor area. The remaining area may have a ceiling with a
minimum height of 5 feet, 0 inches. Minimum height under dropped ducts,
beams, etc. shall be 6 feet, 4 inches.
(b) Hallways and foyers shall have a minimum ceiling height of 6
feet, 6 inches.

Sec. 3280.105 Exit facilities; exterior doors.

(a) Number and location of exterior doors. Manufactured homes shall
have a minimum of two exterior doors located remote from each other.
(1) Required egress doors shall not be located in rooms where a
lockable interior door must be used in order to exit.
(2) In order for exit doors to be considered remote from each other,
they must comply with all of the following:
(i) Both of the required doors must not be in the same room or in a
group of rooms which are not defined by fixed walls.
(ii) Single wide units. Doors may not be less than 12 ft. c-c from
each other as measured in any straight line direction regardless of the
length of path of travel between doors.
(iii) Double wide units. Doors may not be less than 20 ft. c-c from
each other as measured in any straight line direction regardless of the
length of path of travel between doors.
(iv) One of the required exit doors must be accessible from the
doorway of each bedroom without traveling more than 35 ft.
(b) Door design and construction. (1) Exterior swinging doors shall
be constructed in accordance with Sec. 3280.405 the ``Standard for
Swinging Exterior Passage Doors for Use in Manufactured Homes''.
Exterior sliding glass doors shall be constructed in accordance with
Sec. 3280.403 the ``Standard for Windows and Sliding Glass Doors Used in
Manufactured Homes''.
(2) All exterior swinging doors shall provide a minimum 28 inch wide
by 74 inch high clear opening. All exterior sliding glass doors shall
provide a minimum 28 inch wide by 72 inch high clear opening.
(3) Each swinging exterior door other than screen or storm doors
shall have a key-operated lock that has a deadlocking latch or a key-
operated dead bolt with a passage latch. Locks shall not require the use
of a key for operation from the inside.
(4) All exterior doors, including storm and screen doors, opening
outward shall be provided with a safety door check.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 50 FR 9269, Mar. 7, 1985]

Sec. 3280.106 Exit facilities; egress windows and devices.

(a) Every room designed expressly for sleeping purposes, unless it
has an exit door (see Sec. 3280.105), shall have at least one outside
window or approved exit device which meets the requirements of
Sec. 3280.404, the ``Standard for Egress Windows and Devices for Use in
Manufactured Homes.''
(b) The bottom of the window opening shall not be more than 36
inches above the floor.
(c) Locks, latches, operating handles, tabs, and any other window
screen or storm window devices which need to be operated in order to
permit exiting, shall not be located in excess of 54 inches from the
finished floor.
(d) Integral rolled-in screens shall not be permitted in an egress
window unless the window is of the hinged-type.

[49 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 49 FR 36086, Sept. 14, 1984; 52 FR 4581, Feb. 12, 1987]

Sec. 3280.107 Interior privacy.

Bathroom and toilet compartment doors shall be equipped with a
privacy lock.

Sec. 3280.108 Interior passage.

(a) Interior doors having passage hardware without a privacy lock,
or with a privacy lock not engaged, shall

[[Page 115]]

open from either side by a single movement of the hardware mechanism in
any direction.
(b) Each manufactured home interior door, when provided with a
privacy lock, shall have a privacy lock that has an emergency release on
the outside to permit entry when the lock has been locked by a locking
knob, lever, button, or other locking device on the inside.

Sec. 3280.109 Room requirements.

(a) Every manufactured home shall have at least one living area with
not less than 150 sq. ft. of gross floor area.
(b) Rooms designed for sleeping purposes shall have a minimum gross
square foot floor area as follows:
(1) All bedrooms shall have at least 50 sq. ft. of floor area.
(2) Bedrooms designed for two or more people shall have 70 sq. ft.
of floor area plus 50 sq. ft. for each person in excess of two.
(c) Every room designed for sleeping purposes shall have accessible
clothes hanging space with a minimum inside depth of 22 inches and shall
be equipped with a rod and shelf.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
and further redesignated at 58 FR 55004, Oct. 25, 1993]

Sec. 3280.110 Minimum room dimensions.

The gross floor area required by Sec. 3280.110 (a) and (b) shall
have no clear horizontal dimension less than 5 feet except as permitted
by Sec. 3280.102(a).

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
and further redesignated at 58 FR 55004, Oct. 25, 1993]

Sec. 3280.111 Toilet compartments.

Each toilet compartment shall be a minimum of 30 inches in width,
except, when the toilet is located adjacent to the short dimension of
the tub, the distance from the tub to the center line of the toilet
shall not be less than 12 inches. At least 21 inches of clear space
shall be provided in front of each toilet.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
and further redesignated at 58 FR 55004, Oct. 25, 1993]

Sec. 3280.112 Hallways.

Hallways shall have a minimum horizontal dimension of 28 inches
measured from the interior finished surface to the interior finished
surface of the opposite wall. When appliances are installed in a laundry
area, the measurement shall be from the front of the appliance to the
opposite finished interior surface. When appliances are not installed
and a laundry area is provided, the area shall have a minimum clear
depth of 27 inches in addition to the 28 inches required for passage. In
addition, a notice of the available clearance for washer/dryer units
shall be posted in the laundry area. Minor protrusions into the minimum
hallway width by doorknobs, trim, smoke detectors or light fixtures are
permitted.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
and further redesignated at 58 FR 55004, Oct. 25, 1993]

Sec. 3280.113 Glass and glazed openings.

(a) Windows and sliding glass doors. All windows and sliding glass
doors shall meet the requirements of Sec. 3280.403 the ``Standard for
Windows and Sliding Glass Doors Used in Manufactured Homes''.
(b) Safety glazing. Glazing in all entrance or exit doors, sliding
glass doors, units (fixed or moving sections), unframed glass doors,
unbacked mirrored wardrobe doors (i.e., mirrors not secured to a backing
capable of being the door itself), shower and bathtub enclosures and
surrounds to a height of 6 feet above the bathroom floor level, storm
doors or combination doors, and in panels located within 12 inches on
either side of exit or entrance doors shall be of a safety glazing
material. Safety glazing material is considered to be any glazing
material capable of passing the requirements of Safety Performance
Specifications and Methods of Test for Safety Glazing Materials Used in
Buildings, ANSI Z97.1-1984.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4581, Feb. 12, 1987. Redesignated at 58 FR 55004,
Oct. 25, 1993]

[[Page 116]]

Subpart C--Fire Safety

Source: 49 FR 32008, Aug. 9, 1984, unless otherwise noted.

Sec. 3280.201 Scope.

The purpose of this subpart is to set forth requirements that will
assure reasonable fire safety to the occupants by reducing fire hazards
and by providing measures for early detection.

Sec. 3280.202 Definitions.

The following definitions are applicable to subparts C, H, and I of
the Standards:
Combustible material: Any material not meeting the definition of
limited-combustible or non-combustible material.
Flame-spread rating: The measurement of the propagation of flame on
the surface of materials or their assemblies as determined by recognized
standard tests conducted as required by this subpart.
Interior finish: The surface material of walls, fixed or movable
partitions, ceilings, columns, and other exposed interior surfaces
affixed to the home's structure including any materials such as paint or
wallpaper and the substrate to which they are applied. Interior finish
does not include:
(1) Trim and sealant 2 inches or less in width adjacent to the
cooking range and in furnace and water heater spaces provided it is
installed in accordance with the requirements of Sec. 3280.203(b)(3) or
(4), and trim 6 inches or less in width in all other areas;
(2) Windows and frames;
(3) Single doors and frames and a series of doors and frames not
exceeding 5 feet in width;
(4) Skylights and frames;
(5) Casings around doors, windows, and skylights not exceeding 4
inches in width;
(6) Furnishings which are not permanently affixed to the home's
structure;
(7) Baseboards not exceeding 6 inches in height;
(8) Light fixtures, cover plates of electrical receptacle outlets,
switches, and other devices;
(9) Decorative items attached to walls and partitions (i.e.,
pictures, decorative objects, etc.) constituting no more than 10% of the
aggregate wall surface area in any room or space not more than 32 square
feet in surface area, whichever is less;
(10) Plastic light diffusers when suspended from a material which
meets the interior finish provisions of Sec. 3280.203(b);
(11) Coverings and surfaces of exposed wood beams; and
(12) Decorative items including the following:
(i) Non-structural beams not exceeding 6 inches in depth and 6
inches in width and spaced not closer than 4 feet on center;
(ii) Non-structural lattice work;
(iii) Mating and closure molding; and
(iv) Other items not affixed to the home's structure.
Limited combustible: A material meeting:
(1) The definition of Article 2-3 or NFPA 220-1992; or
(2) \5/16\-inch or thicker gypsum board.
Noncombustible material: A material meeting the definition of
contained in NFPA 220-1992.
Single-station alarm device: An assembly incorporating the smoke
detector sensor, the electrical control equipment, and the alarm-
sounding device in one unit.
Smoke detector: A wall-mounted detector of the ionization chamber or
photoelectric type which detects visible or invisible particles of
combustion and operates from a 120V AC source of current.

[58 FR 55004, Oct. 25, 1993]

Sec. 3280.203 Flame spread limitations and fire protection requirements.

(a) Establishment of flame spread rating. The surface flame spread
rating of interior-finish material shall not exceed the value shown in
Sec. 3280.203(b) when tested by ``Standard Test Method for Surface
Burning Characteristics of Building Materials, ASTM E 84-91a'' except
that the surface flame spread rating of interior-finish materials
required by Sec. 3280.203(b)(5) and (6) may be determined by using the
``Standard Test Method for Surface Flammability of Materials Using a
Radiant Heat Energy Source, ASTM E 162-90''. However, the following
materials need not be tested to establish their flame spread

[[Page 117]]

rating unless a lower rating is required by these standards.
(1) Flame-spread rating--76 to 200.
(i) .035-inch or thicker high pressure laminated plastic panel
countertop;
(ii) \1/4\-inch or thicker unfinished plywood with phenolic or urea
glue;
(iii) Unfinished dimension lumber (1-inch or thicker nominal
boards);
(iv) \3/8\-inch or thicker unfinished particleboard with phenolic or
urea binder;
(v) Natural gum-varnished or latex- or alkyd-painted:
(A) \1/4\-inch or thicker plywood, or
(B) \3/8\-inch or thicker particleboard, or
(C) 1-inch or thicker nominal board;
(vi) \5/16\-inch gypsum board with decorative wallpaper; and
(vii) \1/4\-inch or thicker unfinished hardboard,
(2) Flame-spread rating-25 to 200,
(i) Painted metal;
(ii) Mineral-base acoustic tile;
(iii) \5/16\-inch or thicker unfinished gypsum wallboard (both
latex- or alkyd-painted); and
(iv) Ceramic tile.

(The above-listed material applications do not waive the requirements of
Sec. 3280.203(c) or Sec. 3280.204 of this subpart.)

(b) Flame-spread rating requirements.
(1) The interior finish of all walls, columns, and partitions shall
not have a flame spread rating exceeding 200 except as otherwise
specified herein.
(2) Ceiling interior finish shall not have a flame spread rating
exceeding 75.
(3) Walls adjacent to or enclosing a furnace or water heater and
ceilings above them shall have an interior finish with a flame spread
rating not exceeding 25. Sealants and other trim materials 2 inches or
less in width used to finish adjacent surfaces within these spaces are
exempt from this provision provided that all joints are completely
supported by framing members or by materials having a flame spread
rating not exceeding 25.
(4) Exposed interior finishes adjacent to the cooking range shall
have a flame spread rating not exceeding 50, except that backsplashes
not exceeding 6 inches in height are exempted. Adjacent surfaces are the
exposed vertical surfaces between the range top height and the overhead
cabinets and/or ceiling and within 6 horizontal inches of the cooking
range. (Refer also to Sec. 3280.204(a), Kitchen Cabinet Protection.)
Sealants and other trim materials 2 inches or less in width used to
finish adjacent surfaces are exempt from this provision provided that
all joints are completely supported by a framing member.
(5) Kitchen cabinet doors, countertops, backsplashes, exposed
bottoms, and end panels shall have a flame spread rating not to exceed
200. Cabinet rails, stiles, mullions, and top strips are exempted.
(6) Finish surfaces of plastic bathtubs, shower units, and tub or
shower doors shall not exceed a flame spread rating of 200.
(c) Fire protective requirements.
(1) Materials used to surface the following areas shall be of
limited combustible material (e.g., \5/16\-inch gypsum board, etc.):
(i) The exposed wall adjacent to the cooking range (see
Sec. 3280.203(b)(4));
(ii) Exposed bottoms and sides of kitchen cabinets as required by
Sec. 3280.204;
(iii) Interior walls and ceilings enclosing furnace and/or water
heater spaces; and
(iv) Combustible doors which provide interior or exterior access to
furnace and/or water heater spaces. The surface may be interrupted for
louvers ventilating the enclosure. However, the louvers shall not be
constructed of a material of greater combustibility than the door itself
(e.g., plastic louvers on a wooden door).
(2) No burner of a surface cooking unit shall be closer than 12
horizontal inches to a window or an exterior door with glazing.

[49 FR 32008, Aug. 9, 1984, as amended at 58 FR 55005, Oct. 25, 1993]

Sec. 3280.204 Kitchen cabinet protection.

(a) The bottom and sides of combustible kitchen cabinets over
cooking ranges to a horizontal distance of 6 inches from the outside
edge of the cooking range shall be protected with at least \5/16\-inch
thick gypsum board or

[[Page 118]]

equivalent limited combustible material. One-inch nominal framing
members and trim are exempted from this requirement. The cabinet area
over the cooking range or cooktops shall be protected by a metal hood
(26-gauge sheet metal, or .017 stainless steel, or .024 aluminum, or
.020 copper) with not less than a 3-inch eyebrow projecting horizontally
from the front cabinet face. The \5/16\-inch thick gypsum board or
equivalent material which is above the top of the hood may be supported
by the hood. A \3/8\-inch enclosed air space shall be provided between
the bottom surface of the cabinet and the gypsum board or equivalent
material. The hood shall be at least as wide as the cooking range.
(b) The 3-inch metal eyebrow required by paragraph (a) of this
section will project from the front and rear cabinet faces when there is
no adjacent surface behind the range, or the \5/16\-inch thick gypsum
board or equivalent material shall be extended to cover all exposed rear
surfaces of the cabinet.
(c) The metal hood required by paragraphs (a) and (b) of this
section can be omitted when an oven of equivalent metal protection is
installed between the cabinet and the range and all exposed cabinet
surfaces are protected as described in paragraph (a) of this section.
(d) When a manufactured home is designed for the future installation
of a cooking range, the metal hood and cabinet protection required by
paragraph (a) of this section and the wall-surfacing protection behind
the range required by Sec. 3280.203 shall be installed in the factory.
(e) Vertical clearance above cooking top. Ranges shall have a
vertical clearance above the cooking top of not less than 24 inches to
the bottom of combustible cabinets.

Sec. 3280.205 Carpeting.

Carpeting shall not be used in a space or compartment designed to
contain only a furnace and/or water heater. Carpeting may be used in
other areas where a furnace or water heater is installed, provided that
it is not located under the furnace or water heater.

Sec. 3280.206 Firestopping.

(a) Firestopping of at least 1-inch nominal lumber, \5/16\-inch
thick gypsum board, or the equivalent, shall be provided to cut off
concealed draft openings between walls and partitions, including furred
spaces, and the roof or floors, so as to retard vertical movement of
fire. In particular, such concealed spaces must be constructed so that
floor-to-ceiling concealed spaces on one floor do not communicate with
any concealed space on another floor, any concealed spaces in the floor,
or any concealed space in the roof cavity. A barrier must be installed
to prevent communication between adjacent concealed spaces.
(1) Where the barrier is vertical, it must be made of exterior or
interior covering(s) equivalent to that used on the nearest exposed wall
surface; and
(2) In all other cases, the barrier must be made of 1-inch nominal
lumber, \5/16\-inch thick gypsum board, or the equivalent.
(b) A space does not lose its character as a concealed draft opening
if it is filled with insulation or other material or if it is blocked by
a barrier other than as required by paragraph (a) of this section.
(c) All openings for pipes and vents and other penetrations in
walls, floors, and ceilings of furnace and water heater spaces shall be
tight-fitted or firestopped. Pipes, vents, and other penetrations are
tight-fitted when they cannot be moved freely in the opening.

Sec. 3280.207 Requirements for foam plastic thermal insulating materials.

(a) General. Foam plastic thermal insulating materials shall not be
used within the cavity of walls (not including doors) or ceilings or be
exposed to the interior of the home unless:
(1) The foam plastic insulating material is protected by an interior
finish of \5/16\-inch thick gypsum board or equivalent material for all
cavities where the material is to be installed; or
(2) The foam plastic is used as a sheathing or siding backerboard,
and it:
(i) Has a flame spread rating of 75 or less and a smoke-developed
rating of 450 or less (not including outer covering of sheathing);

[[Page 119]]

(ii) Does not exceed \3/8\-inch in thickness; and
(iii) Is separated from the interior of the manufactured home by a
minimum of 2 inches of mineral fiber insulation or an equivalent thermal
barrier; or
(3) The foam plastic insulating material has been previously
accepted by the Department for use in wall and/or ceiling cavities of
manufactured homes, and it is installed in accordance with any
restrictions imposed at the time of that acceptance; or
(4) The foam plastic insulating material has been tested as required
for its location in wall and/or ceiling cavities in accordance with
testing procedures described in the Illinois Institute of Technology
Research Institute (IITRI) Report, ``Development of Mobile Home Fire
Test Methods to Judge the Fire Safe Performance of Foam Plastic, J-
6461,'' or other full-scale fire tests accepted by the Department, and
it is installed in a manner consistent with the way the material was
installed in the foam plastic test module. The materials shall be
capable of meeting the following acceptance criteria required for their
location.
(i) Wall assemblies. The foam plastic system shall demonstrate
equivalent or superior performance to the control module as determined
by:
(A) Time to reach flashover (600 deg. C in the upper part of the
room);
(B) Time to reach an oxygen (O2) level of 14% (rate of
O2 depletion), a carbon monoxide (CO) level of 1%, a carbon
dioxide (CO2) level of 6%, and a smoke level of 0.26 optical
density/meter measured at 5 feet high in the doorway; and
(C) Rate of change concentration for O2, CO,
CO2 and smoke measured 3 inches below the top of the doorway.
(ii) Ceiling assemblies. A minimum of three valid tests of the foam
plastic system and one valid test of the control module shall be
evaluated to determine if the foam plastic system domonstrates
equivalent or superior performance to the control module. Individual
factors to be evaluated include intensity of cavity fire (temperature-
time) and post-test damage.
(iii) Post-test damage assessment for wall and ceiling assemblies.
The overall performance of each total system shall also be evaluated in
determining the acceptability of a particular foam plastic insulating
material.
(b) All foam plastic thermal insulating materials used in
manufactured housing shall have a flame spread rating of 75 or less (not
including outer covering or sheathing) and a maximum smoke-developed
rating of 450.

Sec. 3280.208 Fire detection equipment.

(a) General. At least one smoke detector (which may be a single
station alarm device) shall be installed in the home in the location(s)
specified in paragraph (b) of this section.
(b) Smoke detector locations. (1) A smoke detector shall be
installed on any wall in the hallway or space communicating with each
bedroom area between the living area and the first bedroom door unless a
door(s) separates the living area from that bedroom area, in which case
the detector(s) shall be installed on the living area side as close to
the door(s) as practicable. Homes having bedroom areas separated by any
one or combination of common-use areas such as kitchen, dining room,
living room, or family room (but not a bathroom or utility room), shall
have at least one detector protecting each bedroom area.
(2) When located in hallways, the detector shall be between the
return air intake and the living area.
(3) When a home is equipped or designed for future installation of a
roof-mounted evaporative cooler or other equipment discharging
conditioned air through a ceiling grille into the living space
environment, the detector closest to the air discharge shall be located
no closer than three horizontal feet from any discharge grille.
(4) A smoke detector shall not be placed in a location which impairs
its effectiveness.
(c) Labeling. Smoke detectors shall be labeled as conforming with
the requirements of Underwriters' Laboratories Standard No. 217--Fourth
Edition 1993 for Single and Multiple Station Smoke Detectors.
(d) Installation. Each smoke detector shall be installed in
accordance with its listing. The top of the detector shall be located on
a wall 4 inches to 12 inches, or at a distance permitted by

[[Page 120]]

the listing, below the ceiling. However, when a detector is mounted on
an interior wall below a sloping ceiling, it shall be located 4 inches
to 12 inches below the intersection of the connecting exterior wall and
the sloping ceiling (cathedral ceiling). The required detector(s) shall
be attached to an electrical outlet box and the detector connected by a
permanent wiring method into a general electrical circuit. There shall
be no switches in the circuit to the detector between the over-current
protection device protecting the branch circuit and the detector. Smoke
detector(s) shall not be placed on the same branch circuit or any
circuit protected by a ground fault circuit interrupter.

[49 FR 32008, Aug. 9, 1984, as amended at 58 FR 55005, Oct. 25, 1993]

Sec. 3280.209 Fire testing.

All fire testing conducted in accordance with this subpart shall be
performed by nationally recognized testing laboratories which have
expertise in fire technology. In case of dispute, the Secretary shall
determine if a particular agency is qualified to perform such fire
tests.

[49 FR 32011, Aug. 9, 1984]

Subpart D--Body and Frame Construction Requirements

Sec. 3280.301 Scope.

This subpart covers the minimum requirements for materials,
products, equipment and workmanship needed to assure that the
manufactured home will provide:
(a) Structural strength and rigidity,
(b) Protection against corrosion, decay, insects and other similar
destructive forces,
(c) Protection against hazards of windstorm,
(d) Resistance to the elements, and
(e) Durability and economy of maintenance.

Sec. 3280.302 Definitions.

The following definitions are applicable to subpart D only:
Anchoring equipment: means straps, cables, turnbuckles, and chains,
including tensioning devices, which are used with ties to secure a
manufactured home to ground anchors.
Anchoring system: means a combination of ties, anchoring equipment,
and ground anchors that will, when properly designed and installed,
resist overturning and lateral movement of the manufactured home from
wind forces.
Diagonal tie: means a tie intended to primarily resist horizontal
forces, but which may also be used to resist vertical forces.
Footing: means that portion of the support system that transmits
loads directly to the soil.
Ground anchor: means any device at the manufactured home stand
designed to transfer manufactured home anchoring loads to the ground.
Loads: (1) Dead load: means the weight of all permanent construction
including walls, floors, roof, partition, and fixed service equipment.
(2) Live load: means the weight superimposed by the use and
occupancy of the manufactured home, including wind load and snow load,
but not including dead load.
(3) Wind load: means the lateral or vertical pressure or uplift on
the manufactured home due to wind blowing in any direction.
Main frame: means the structural component on which is mounted the
body of the manufactured home.
Pier: means that portion of the support system between the footing
and manufactured home exclusive of caps and shims.
Sheathing: means material which is applied on the exterior side of a
building frame under the exterior weather resistant covering.
Stabilizing devices: means all components of the anchoring and
support system such as piers, footings, ties, anchoring equipment,
ground anchors, and any other equipment which supports the manufactured
home and secures it to the ground.
Support system: means a combination of footings, piers, caps, and
shims that will, when properly installed, support the manufactured home.
Tie: means straps, cable, or securing devices used to connect the
manufactured home to ground anchors.

[[Page 121]]

Vertical tie: means a tie intended to resist the uplifting or
overturning forces.

[58 FR 55005, Oct. 25, 1993; 59 FR 15113, Mar. 31, 1994]

Sec. 3280.303 General requirements.

(a) Minimum requirements. The design and construction of a
manufactured home shall conform with the provisions of this standard.
Requirements for any size, weight, or quality of material modified by
the terms of minimum, not less than, at least, and similar expressions
are minimum standards. The manufacturer or installer may exceed these
standards provided such deviation does not result in any inferior
installation or defeat the purpose and intent of this standard.
(b) Construction. All construction methods shall be in conformance
with accepted engineering practices to insure durable, livable, and safe
housing and shall demonstrate acceptable workmanship reflecting
journeyman quality of work of the various trades.
(c) Structural analysis. The strength and rigidity of the component
parts and/or the integrated structure shall be determined by engineering
analysis or by suitable load tests to simulate the actual loads and
conditions of application that occur. (See subparts E and J.)
(d) [Reserved]
(e) New materials and methods. (1) Any new material or method of
construction not provided for in this standard and any material or
method of questioned suitability proposed for use in the manufacture of
the structure shall nevertheless conform in performance to the
requirements of this standard.
(2) Unless based on accepted engineering design for the use
indicated, all new manufactured home materials, equipment, systems or
methods of construction not provided for in this standard shall be
subjected to the tests specified in paragraph (g) of this section.
(f) Allowable design stress. The design stresses of all materials
shall conform to accepted engineering practice. The use of materials not
certified as to strength or stress grade shall be limited to the minimum
allowable stresses under accepted engineering practice.
(g) Alternative test procedures. In the absence of recognized
testing procedures either in these standards or the applicable
provisions of those standards incorporated by reference, the
manufacturer electing this option shall develop or cause to be developed
testing procedures to demonstrate the structural properties and
significant characteristics of the material, assembly, subassembly
component or member. Such testing procedures shall become part of the
manufacturer's approved design. (Refer to Sec. 3280.3.)
(1) Testing procedures so developed shall be submitted to the
Department for approval.
(2) Upon notification of approval, the alternative test procedure is
considered acceptable.
(3) Such tests shall be witnessed by an independent licensed
professional engineer or architect or by a recognized testing
organization. Copies of the test results shall be kept on file by the
manufactured home manufacturer.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55005, Oct. 25, 1993; 59 FR 2469, Jan. 14, 1994]

Sec. 3280.304 Materials.

(a) Dimension and board lumber shall not exceed 19 percent moisture
content at time of installation.
(b)(1) Standards for some of the generally used materials and
methods of construction are listed in the following table.

Steel

Specification for Aluminum Structures Construction Manual Series--
Section 1, Fifth Edition--1986, The Aluminum Association.
Specification for Structural Steel Buildings--Allowable Stress
Design and Plastic Design--AISC--June 1, 1989.
The following parts of this reference standard are not applicable:
1.3.3, 1.3.4, 1.3.5, 1.3.6, 1.4.6, 1.5.1.5, 1.5.5, 1.6, 1.7, 1.8, 1.9,
1.10.4 through 1.10.7, 1.10.9, 1.11, 1.13, 1.14.5, 1.17.7 through
1.17.9, 1.19.1, 1.19.3, 1.20, 1.21, 1.23.7, 1.24, 1.25.1 through 1.25.5,
1.26.4, 2.3, 2.4, 2.8 through 2.10.
Specification for the Design of Cold-Formed Steel Structural
Members--AISI--1986 Edition With 1989 Addendum.

[[Page 122]]

The following parts of this reference standard are not applicable:
3.1.2, 4.2.1, 4.2.4.
Stainless Steel Cold-Formed Structural Design Manual--AISI-1974.
The following part of this reference standard is not applicable:
3.1.2.
Standard Specifications Load Tables and Weight Tables for Steel
Joists and Joist Girders, only Sections 1-6 and the table for ``H series
only'' are applicable--Steel Joist Institute 1992.
Manual for Structural Applications of Steel Cables for Buildings--
AISI-1973.
Standard Specification for Strapping, Flat Steel and Seals--ASTM
D3953-91.

Wood and Wood Products

Basic Hardboard--ANSI/AHA A135.4-1982.
Prefinished Hardboard Paneling--ANSI/AHA A135.5-1988.
Hardboard Siding--ANSI/AHA A135.6-1990.
Interim Voluntary Standard for Hardwood and Decorative Plywood--HPVA
Interim Standard HP-1-1993.
Structural Design Guide for Hardwood Plywood Wall Panels--HPMA
Design Guide HP-SG-86.
For wood products--Structural Glued Laminated Timber--ANSI/AITC
A190.1-1992.
Voluntary Product Standard, Construction and Industrial Plywood--PS-
1-83.
APA Design/Construction Guide, Residential and Commercial--APA E30M-
1993.
Design and Fabrication of All-Plywood Beams, Suppl. 5--APA-H 815D-
1989.
Plywood Design Specification--APA-Y 510Q-1993.
Design and Fabrication of Glued Plywood-Lumber Beams, Suppl. 2--APA-
S 812P-1992.
Design and Fabrication of Plywood Curved Panels, Suppl. 1--APA-S
811M-1990.
Design and Fabrication of Plywood Sandwich Panels, Suppl. 4--APA-U
814G-1990.
Performance Standards and Policies for Structural Use Panels--APA-
PRP-E-108P, E445N-1989.
Design and Fabrication of Plywood Stressed-Skin Panels, Suppl. 3--
APA-U 813K-1990.
National Design Specifications for Wood Construction, 1991 Edition,
With Supplement, Design Values for Wood Construction, AFPA.
Wood Structural Design Data, 1986 Edition With 1992 Revisions, AFPA.
Span Tables for Joists and Rafters--PS-20-70, 1993, AFPA.
Design Values for Joists and Rafters, American Softwood Lumber
Standard Sizes, 1992, AFPA.
Design Specifications for Metal Plate Connected Wood Trusses--TPI-
85.
Wood Particleboard--ANSI A208.1-1989,
Wood Flush Doors--ANSI/NWWDA I.S.1-87.
Wood Windows--ANSI/NWWDA I.S.2-87.
Wood Sliding Patio Doors--NWWDA-I.S.3-88.
Water Repellent Preservative Non Pressure Treatment for Millwork--
NWWDA-I.S.4-81.
Standard Test Methods for Puncture and Stiffness of Paperboard, and
Corrugated and Solid Fiberboard--ASTM D781-68 (73).
Standard Test Methods for Direct Moisture Content Measurement of
Wood and Wood-Base Materials--ASTM D4442.
Standard Test Methods for Use and Calibration of Hand-Held Moisture
Meters--ASTM D4444-92.

Other

Standard Specification for Gypsum Wallboard--ASTM C36-93.

Fasteners

Application and Fastening Schedule: Power-Driven, Mechanically
Driven and Manually Driven Fasteners--HUD-FHA Use of Materials
Bulletin--UM-25d-73.

Unclassified

American Society of Civil Engineering Minimum Design Loads for
Buildings and Other Structures--ANSI/ASCE 7-88.
Performance Standard for Wood-Based Structural Use Panels--PS-2-92,

[[Page 123]]

APA (also known as NIST Standard PS-2-92).
Safety Performance Specifications and Methods of Test for Safety
Glazing Materials Used in Building--ANSI Z97.1-1984.
(2) Materials and methods of construction utilized in the design and
construction of manufactured homes which are covered by the standards in
the following table, or any applicable portion thereof shall comply with
these requirements.
(3) Engineering analysis and testing methods contained in these
references shall be utilized to judge conformance with accepted
engineering practices required in Sec. 3280.303(c).
(4) Materials and methods of installation conforming to these
standards shall be considered acceptable when installed in conformance
with the requirements of this part.
(5) Materials meeting the standards (or the applicable portion
thereof) are considered acceptable unless otherwise specified herein or
unless substantial doubt exists as to conformance.
(c) Wood products shall be identified as complying with the
appropriate standards.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 961, Jan. 4, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 58 FR 55006,
Oct. 25, 1993; 59 FR 15113, Mar. 31, 1994]

Sec. 3280.305 Structural design requirements.

(a) General. Each manufactured home shall be designed and
constructed as a completely integrated structure capable of sustaining
the design load requirements of this standard, and shall be capable of
transmitting these loads to stabilizing devices without exceeding the
allowable stresses or deflections. Roof framing shall be securely
fastened to wall framing, walls to floor structure, and floor structure
to chassis to secure and maintain continuity between the floor and
chassis, so as to resist wind overturning, uplift, and sliding as
imposed by design loads in this part. Uncompressed finished flooring
greater than 1/8 inch in thickness shall not extend beneath load-bearing
walls that are fastened to the floor structure.
(b) Design loads--(1) Design dead loads. Design dead loads shall be
the actual dead load supported by the structural assembly under
consideration.
(2) Design live loads. The design live loads and wind and snow loads
shall be as specified in this section and shall be considered to be
uniformly distributed. The roof live load or snow load shall not be
considered as acting simultaneously with the wind load and the roof live
or snow load and floor live loads shall not be considered as resisting
the overturning moment due to wind.
(3) When engineering calculations are performed, allowable unit
stresses may be increased as provided in the documents referenced in
Sec. 3280.304 except as otherwise indicated in Secs. 3280.304(b)(1) and
3280.306(a).
(4) Whenever the roof slope does not exceed 20 degrees, the design
horizontal wind loads required by Sec. 3280.305(c)(1) may be determined
without including the vertical roof projection of the manufactured home.
However, regardless of the roof slope of the manufactured home, the
vertical roof projection shall be included when determining the wind
loading for split level or clerestory-type roof systems.
(c) Wind, snow, and roof loads--(1) Wind loads--design requirements.
(i) Standard wind loads (Zone I). When a manufactured home is not
designed to resist the wind loads for high wind areas (Zone II or Zone
III) specified in paragraph (c)(1)(ii) of this section, the manufactured
home and each of its wind resisting parts and portions shall be designed
for horizontal wind loads of not less than 15 psf and net uplift load of
not less than 9 psf.
(ii) Wind loads for high wind areas (Zone II and Zone III). When
designed for high wind areas (Zone II and Zone III), the manufactured
home, each of its wind resisting parts (including, but not limited to,
shear walls, diaphragms, ridge beams, and their fastening and anchoring
systems), and its components and cladding materials (including, but not
limited to, roof trusses, wall studs, exterior sheathing, roofing and
siding materials, exterior glazing, and their connections and fasteners)
shall be designed by a Professional Engineer or Architect to resist:

[[Page 124]]

(A) The design wind loads for Exposure C specified in ANSI/ASCE 7-
88, ``Minimum Design Loads for Buildings and Other Structures,'' for a
fifty-year recurrence interval, and a design wind speed of 100 mph, as
specified for Wind Zone II, or 110 mph, as specified for Wind Zone III
(Basic Wind Zone Map); or
(B) The wind pressures specified in the following table:

Table of Design Wind Pressures
------------------------------------------------------------------------
Wind zone II Wind zone III
Element design wind design wind
speed 100 MPH speed 110 MPH
------------------------------------------------------------------------
Anchorage for lateral and vertical
stability (See Sec. 3280.306(a)):
Net Horizontal Drag^1,2... \3\ 39 47
Fastening and Anchorage Systems ^1,2 PSF PSF
Ridge beams and other Main Roof -30 PSF -36 PSF
Support Beams (Beams supporting
expanding room sections, etc.).....
Components and cladding:
Roof trusses \4\ in all areas; \5\ -39 PSF \5\ -47 PSF
trusses shall be doubled within 3'-
0'' from each end of the roof......
Exterior roof coverings, sheathing \5\ -39 PSF \5\ -47 PSF
and fastenings \4\,\6\,\7\ in all
areas except the following.........
Within 3'-0'' from each gable \5\ -73 PSF \5\ -89 PSF
end (overhang at end wall) of
the roof or endwall if no
overhang is provided
\4\,\6\,\7\....................
Within 3'-0'' from the ridge and \5\ -51 PSF \5\ -62 PSF
eave (overhang at sidewall) or
sidewall if no eave is provided
\4\,\6\,\7\....................
Eaves (Overhangs at Sidewalls) \5\ -51 PSF \5\ -62 PSF
\4\,\6\,\7\........................
Gables (Overhangs at Endwalls) \5\ -73 PSF \5\ -89 PSF
\4\,\6\,\7\........................
Wall studs in sidewalls and endwalls,
exterior windows and sliding glass
doors (glazing and framing), exterior
coverings, sheathing and fastenings
\8\:
Within 3'-0'' from each corner 48 58
of the sidewall and endwall.... PSF PSF
All other areas................. 38 46
PSF PSF
------------------------------------------------------------------------
NOTES:

¹ The net horizontal drag of 39 PSF to be used in
calculating Anchorage for Lateral and Vertical Stability and for the
design of Main Wind Force Resisting Systems is based on a distribution
of wind pressures of +0.8 or +24 PSF to the windward wall and -0.5 or
15 PSF to the leeward wall.
² Horizontal drag pressures need not be applied to roof projections when
the roof slope does not exceed 20 degrees.
³ + sign would mean pressures are acting towards or on the structure; -
sign means pressures are acting away from the structure;
sign means forces can act in either direction, towards or away from
the structure.
⁴ Design values in this ``Table'' are only applicable to roof slopes
between 10 degrees (nominal 2/12 slope) and 30 degrees.
⁵ The design uplift pressures are the same whether they are applied
normal to the surface of the roof or to the horizontal projection of
the roof.
⁶ Shingle roof coverings that are secured with 6 fasteners per shingle
through an underlayment which is cemented to a 3/8'' structural rated
roof sheathing need not be evaluated for these design wind pressures.
⁷ Structural rated roof sheathing that is at least 3/8'' in thickness,
installed with the long dimension perpendicular to roof framing
supports, and secured with fasteners at 4'' on center within 3'-0'' of
each gable end or endwall if no overhang is provided and 6'' on center
in all other areas, need not be evaluated for these design wind
pressures.
⁸ Exterior coverings that are secured at 6'' o.c. to a 3/8'' structural
rated sheathing that is fastened to wall framing members at 6'' on
center need not be evaluated for these design wind pressures.

(2) Wind loads--zone designations. The Wind Zone and specific wind
design load requirements are determined by the fastest basic wind speed
(mph) within each Zone and the intended location, based on the Basic
Wind Zone Map, as follows:
(i) Wind Zone I. Wind Zone I consists of those areas on the Basic
Wind Zone Map that are not identified in paragraphs (c)(2)(ii) or (iii)
of this section as being within Wind Zone II or III, respectively.
(ii) Wind Zone II.....100 mph. The following areas are deemed to be
within Wind Zone II of the Basic Wind Zone Map:
Local governments: The following local governments listed by State
(counties, unless specified otherwise):
Alabama: Baldwin and Mobile.
Florida: All counties except those identified in paragraph
(c)(1)(i)(C) of this section as within Wind Zone III.
Georgia: Bryan, Camden, Chatham, Glynn, Liberty, McIntosh.
Louisiana: Parishes of Acadia, Allen, Ascension, Assumption,
Calcasieu, Cameron, East Baton Rouge, East Feliciana, Evangeline,
Iberia, Iberville, Jefferson Davis, LaFayette, Livingston, Pointe
Coupee, St. Helena, St. James, St. John the Baptist, St. Landry, St.
Martin, St. Tammany,

[[Page 125]]

Tangipahoa, Vermillion, Washington, West Baton Rouge, and West
Feliciana.
Maine: Hancock and Washington.
Massachusetts: Barnstable, Bristol, Dukes, Nantucket, and Plymouth.
Mississippi: George, Hancock, Harrison, Jackson, Pearl River, and
Stone.
North Carolina: Beaufort, Brunswick, Camden, Chowan, Columbus,
Craven, Currituck, Jones, New Hanover, Onslow, Pamlico, Pasquotank,
Pender, Perquimans, Tyrrell, and Washington.
South Carolina: Beaufort, Berkeley, Charleston, Colleton,
Dorchester, Georgetown, Horry, Jasper, and Williamsburg.
Texas: Aransas, Brazoria, Calhoun, Cameron, Chambers, Galveston,
Jefferson, Kenedy, Kleberg, Matagorda, Nueces, Orange, Refugio, San
Patricio, and Willacy.
Virginia: Cities of Chesapeake, Norfolk, Portsmouth, Princess Anne,
and Virginia Beach.
(iii) Wind Zone III.....110 mph. The following areas are considered
to be within Wind Zone III of the Basic Wind Zone Map:
(A) States and Territories: The entire State of Hawaii, the coastal
regions of Alaska (as determined by the 90 mph isotach on the ANSI/ASCE
7-88 map), and all of the U.S. Territories of American Samoa, Guam,
Northern Mariana Islands, Puerto Rico, Trust Territory of the Pacific
Islands, and the United States Virgin Islands.
(B) Local governments: The following local governments listed by
State (counties, unless specified otherwise):
Florida: Broward, Charlotte, Collier, Dade, Franklin, Gulf, Hendry,
Lee, Martin, Manatee, Monroe, Palm Beach, Pinellas, and Sarasota.
Louisiana: Parishes of Jefferson, La Fourche, Orleans, Plaquemines,
St. Bernard, St. Charles, St. Mary, and Terrabonne.
North Carolina: Carteret, Dare, and Hyde.
(iv) Consideration of local requirements. For areas where local
building code requirements exceed the design wind speed requirements of
these standards, the Department will consider the adoption through
rulemaking of the more stringent requirements of the State or local
building authority.
(3) Snow and roof loads. (i) Flat, curved and pitched roofs shall be
designed to resist the following live loads, applied downward on the
horizontal projection as appropriate for the design zone marked on the
manufactured home:

------------------------------------------------------------------------
Pounds
per
Zone (see Map in Sec. 3280.305(c)(4)) square
foot
------------------------------------------------------------------------
North Zone.................................................... 40
Middle Zone................................................... 30
South Zone.................................................... 20
------------------------------------------------------------------------

(ii) For exposures in areas (mountainous or other) where snow or
wind records or experience indicate significant differences from the
loads stated above, the Department may establish more stringent
requirements for homes known to be destined for such areas. For snow
loads, such requirements are to be based on a roof snow load of 0.6 of
the ground snow load for areas exposed to wind and a roof snow load of
0.8 of the ground snow load for sheltered areas.
(iii) Eaves and cornices shall be designed for a net uplift pressure
of 2.5 times the design uplift wind pressure cited in
Sec. 3280.305(c)(1)(i) for Wind Zone I, and for the design pressures
cited in Sec. 3280.305(c)(1)(ii) for Wind Zones II and III.
(4) Data plate requirements. The Data Plate posted in the
manufactured home (see Sec. 3280.5) shall designate the wind and roof
load zones or, if designed for higher loads, the actual design external
snow and wind loads for which the home has been designed. The Data Plate
shall include reproductions of the Load Zone Maps shown in this
paragraph (c)(4), with any related information. The Load Zone Maps shall
be not less than either 3\1/2\ in. by 2\1/4\ in., or one-half the size
illustrated in the Code of Federal Regulations.

[[Page 126]]

[GRAPHIC] [TIFF OMITTED] TR14JA94.000

[[Page 127]]

[GRAPHIC] [TIFF OMITTED] TR20OC97.004

(d) Design load deflection. (1) When a structural assembly is
subjected to total design live loads, the deflection for structural
framing members shall not exceed the following (where L equals the clear
span between supports or two times the length of a cantilever):

[[Page 128]]

Floor--L/240
Roof and ceiling--L/180
Headers, beams, and girders (vertical load)--L/180
Walls and partitions--L/180
(2) The allowable eave or cornice deflection for uplift is to be
measured at the design uplift load of 9 psf for Wind Zone I, and at the
design uplift pressure cited in paragraph (c)(1)(ii) of this section for
Wind Zones II and III. The allowable deflection shall be (2 x Lc)/180,
where Lc is the measured horizontal eave projection from the wall.
(e) Fastening of structural systems. (1) Roof framing shall be
securely fastened to wall framing, walls to floor structure, and floor
structure to chassis to secure and maintain continuity between the floor
and chassis, so as to resist wind overturning, uplift, and sliding as
specified in this part.
(2) For Wind Zones II and III, roof trusses shall be secured to
exterior wall framing members (studs), and exterior wall framing members
(studs) shall be secured to floor framing members, with 26 gage minimum
steel strapping or brackets or by a combination of 26 gage minimum steel
strapping or brackets and structural rated wall sheathing that overlaps
the roof and floor. Steel strapping or brackets shall be installed at a
maximum spacing of 24" on center in Wind Zone II and at a maximum of 16"
on center in Wind Zone III. The number and type of fasteners used to
secure the steel straps or brackets or structural sheathing shall be
capable of transferring all uplift forces between elements being joined.
(f) Walls. The walls shall be of sufficient strength to withstand
the load requirements as defined in Sec. 3280.305(c) of this part,
without exceeding the deflections as specified in Sec. 3280.305(d). The
connections between the bearing walls, floor, and roof framework members
shall be fabricated in such a manner as to provide support for the
material used to enclose the manufactured home and to provide for
transfer of all lateral and vertical loads to the floor and chassis.
(1) Except where substantiated by engineering analysis or tests,
studs shall not be notched or drilled in the middle one-third of their
length.
(2) Interior walls and partitions shall be constructed with
structural capacity adequate for the intended purpose and shall be
capable of resisting a horizontal load of not less than five pounds per
square foot. An allowable stress increase of 1.33 times the permitted
published design values may be used in the design of wood framed
interior partitions. Finish of walls and partitions shall be securely
fastened to wall framing.
(g) Floors. (1) Floor assemblies shall be designed in accordance
with accepted engineering practice standards to support a minimum
uniform live load of 40 lb/ft \2\ plus the dead load of the materials.
In addition (but not simultaneously), floors shall be able to support a
200-pound concentrated load on a one-inch diameter disc at the most
critical location with a maximum deflection not to exceed one-eighth
inch relative to floor framing. Perimeter wood joists of more than six
inches depth shall be stabilized against overturning from superimposed
loads as follows: at ends by solid blocking not less than two-inch
thickness by full depth of joist, or by connecting to a continuous
header not less than two-inch thickness and not less than the depth of
the joist with connecting devices; at eight-feet maximum intermediate
spacing by solid blocking or by wood cross-bridging of not less than one
inch by three inches, metal cross-bridging of equal strength, or by
other approved methods.
(2) Wood, wood fiber or plywood floors or subfloors in kitchens,
bathrooms (including toilet compartments), laundry areas, water heater
compartments, and any other areas subject to excessive moisture shall be
moisture resistant or shall be made moisture resistant by sealing or by
an overlay of nonabsorbent material applied with water-resistant
adhesive. Use of one of the following methods would meet this
requirement:
(i) Sealing the floor with a water-resistant sealer; or
(ii) Installing an overlay of a non-absorbent floor covering
material applied with water-resistant adhesive; or
(iii) Direct application of a water-resistant sealer to the exposed
wood floor

[[Page 129]]

area when covered with a non-absorbent overlay; or
(iv) The use of a non-absorbent floor covering which may be
installed without a continuous application of a water-resistant adhesive
or sealant when the floor covering meets the following criteria:
(A) The covering is a continuous membrane with any seams or patches
seam bonded or welded to preserve the continuity of the floor covering;
and
(B) The floor is protected at all penetrations in these areas by
sealing with a compatible water-resistant adhesive or sealant to prevent
moisture from migrating under the nonabsorbent floor covering; and
(C) The covering is fastened around the perimeter of the subfloor in
accordance with the floor covering manufacturer's instructions; and,
(D) The covering is designed to be installed to prevent moisture
penetration without the use of a water-resistant adhesive or sealer
except as required in this paragraph (g). The vertical edges of
penetrations for plumbing shall be covered with a moisture-resistant
adhesive or sealant. The vertical penetrations located under the bottom
plates of perimeter walls of rooms, areas, or compartments are not
required to be sealed; this does not include walls or partitions within
the rooms or areas.
(3) Carpet or carpet pads shall not be installed under concealed
spaces subject to excessive moisture, such as plumbing fixture spaces,
floor areas under installed laundry equipment. Carpet may be installed
in laundry space provided:
(i) The appliances are not provided;
(ii) The conditions of paragraph (g)(2) of this section are
followed; and
(iii) Instructions are provided to remove carpet when appliances are
installed.
(4) Except where substantiated by engineering analysis or tests:
(i) Notches on the ends of joists shall not exceed one-fourth the
joist depth.
(ii) Holes bored in joists shall not be within 2 inches of the top
or bottom of the joist, and the diameter of any such hole shall not
exceed one-third the depth of the joist.
(iii) Notches in the top or bottom of the joists shall not exceed
one-sixth the depth and shall not be located in the middle third of the
span.
(5) Bottom board material (with or without patches) shall meet or
exceed the level of 48 inch-pounds of puncture resistance as tested by
the Beach Puncture Test in accordance with Standard Test Methods for
Puncture and Stiffness of Paperboard, and Corrugated and Solid
Fiberboard, ASTM D-781-1968 (73). The material shall be suitable for
patches and the patch life shall be equivalent to the material life.
Patch installation instruction shall be included in the manufactured
home manufacturer's instructions.
(h) Roofs. (1) Roofs shall be of sufficient strength to withstand
the load requirements as defined in Sec. 3280.305 (b) and (c) without
exceeding the deflections specified in Sec. 3280.305(d). The connections
between roof framework members and bearing walls shall be fabricated in
such a manner to provide for the transfer of design vertical and
horizontal loads to the bearing walls and to resist uplift forces.
(2) Roofing membranes shall be of sufficient rigidity to prevent
deflection which would permit ponding of water or separation of seams
due to wind, snow, ice, erection or transportation forces.
(3) Cutting of roof framework members for passage of electrical,
plumbing or mechanical systems shall not be allowed except where
substantiated by engineering analysis.
(4) All roof penetrations for electrical, plumbing or mechanical
systems shall be properly flashed and sealed. In addition, where a metal
roof membrane is penetrated, a wood backer shall be installed. The
backer plate shall be not less than \5/16\ inch plywood, with exterior
glues, secured to the roof framing system beneath the metal roof, and
shall be of a size to assure that all screws securing the flashing are
held by the backer plate.
(i) Frame construction. The frame shall be capable of transmitting
all design loads to stabilizing devices without exceeding the allowable
load and deflections of this section. The frame shall also be capable of
withstanding the effects of transportation shock and vibration without
degradation as required by subpart J.

[[Page 130]]

(1) Welded connections. (i) All welds shall be made in accordance
with the applicable provisions of the Specification for Structural Steel
Buildings, Allowable Stress Design and Plastic Design, AISC, June 1,
1989. The Specification for the Design of Cold-Formed Steel Structural
Members, AISI-1986 with 1989 addendum, and the Stainless Steel Cold-
Formed Structural Design Manual, AISI-1974.
(ii) Regardless of the provisions of any reference standard
contained in this subpart, deposits of weld slag or flux shall be
required to be removed only from welded joints at the following
locations:
(A) Drawbar and coupling mechanisms;
(B) Main member splices, and
(C) Spring hanger to main member connections.
(2) Protection of metal frames against corrosion. Metal frames shall
be made corrosion resistant or protected against corrosion. Metal frames
may be protected against corrosion by painting.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 44 FR 66195, Nov. 19, 1979; 52 FR 4582, Feb. 12, 1987; 58
FR 55006, Oct. 25, 1993; 59 FR 2469, Jan. 14, 1994; 59 FR 15113, 15114,
Mar. 31, 1994; 62 FR 54547, Oct. 20, 1997]

Sec. 3280.306 Windstorm protection.

(a) Provisions for support and anchoring systems. Each manufactured
home shall have provisions for support/anchoring or foundation systems
that, when properly designed and installed, will resist overturning and
lateral movement (sliding) of the manufactured home as imposed by the
respective design loads. For Wind Zone I, the design wind loads to be
used for calculating resistance to overturning and lateral movement
shall be the simultaneous application of the wind loads indicated in
Sec. 3280.305(c)(1)(i), increased by a factor of 1.5. The 1.5 factor of
safety for Wind Zone I is also to be applied simultaneously to both the
vertical building projection, as horizontal wind load, and across the
surface of the full roof structure, as uplift loading. For Wind Zones II
and III, the resistance shall be determined by the simultaneous
application of the horizontal drag and uplift wind loads, in accordance
with Sec. 3280.305(c)(1)(ii). The basic allowable stresses of materials
required to resist overturning and lateral movement shall not be
increased in the design and proportioning of these members. No
additional shape or location factors need to be applied in the design of
the tiedown system. The dead load of the structure may be used to resist
these wind loading effects in all Wind Zones.
(1) The provisions of this section shall be followed and the support
and anchoring systems shall be designed by a Registered Professional
Engineer or Architect.
(2) The manufacturer of each manufactured home is required to make
provision for the support and anchoring systems but is not required to
provide the anchoring equipment or stabilizing devices. When the
manufacturer's installation instructions provide for the main frame
structure to be used as the points for connection of diagonal ties, no
specific connecting devices need be provided on the main frame
structure.
(b) Contents of instructions. (1) The manufacturer shall provide
printed instructions with each manufactured home specifying the location
and required capacity of stabilizing devices on which the design is
based. The manufacturer shall provide drawings and specifications
certified by a registered professional engineer or architect indicating
at least one acceptable system of anchoring, including the details of
required straps or cables, their end connections, and all other devices
needed to transfer the wind loads from the manufactured home to an
anchoring or foundation system.
(2) For anchoring systems, the instructions shall indicate:
(i) The minimum anchor capacity required;
(ii) That anchors should be certified by a professional engineer,
architect, or a nationally recognized testing laboratory as to their
resistance, based on the maximum angle of diagonal tie and/or vertical
tie loading (see paragraph (c)(3) of this section) and angle of anchor
installation, and type of soil in which the anchor is to be installed;
(iii) That ground anchors should be embedded below the frost line
and be at

[[Page 131]]

least 12 inches above the water table; and
(iv) That ground anchors should be installed to their full depth,
and stabilizer plates should be installed to provide added resistance to
overturning or sliding forces.
(v) That anchoring equipment should be certified by a registered
professional engineer or architect to resist these specified forces in
accordance with testing procedures in ASTM Standard Specification D3953-
91, Standard Specification for Strapping, Flat Steel and Seals.
(c) Design criteria. The provisions made for anchoring systems shall
be based on the following design criteria for manufactured homes.
(1) The minimum number of ties provided per side of each home shall
resist design wind loads required in Sec. 3280.305(c)(1).
(2) Ties shall be as evenly spaced as practicable along the length
of the manufactured home, with not more than two (2) feet open-end
spacing on each end.
(3) Vertical ties or straps shall be positioned at studs. Where a
vertical tie and a diagonal tie are located at the same place, both ties
may be connected to a single anchor, provided that the anchor used is
capable of carrying both loadings, simultaneously.
(4) Add-on sections of expandable manufactured homes shall have
provisions for vertical ties at the exposed ends.
(d) Requirements for ties. Manufactured homes in Wind Zone I require
only diagonal ties. These ties shall be placed along the main frame and
below the outer side walls. All manufactured homes designed to be
located in Wind Zones II and III shall have a vertical tie installed at
each diagonal tie location.
(e) Protection requirements. Protection shall be provided at sharp
corners where the anchoring system requires the use of external straps
or cables. Protection shall also be provided to minimize damage to
siding by the cable or strap.
(f) Anchoring equipment--load resistance. Anchoring equipment shall
be capable of resisting an allowable working load equal to or exceeding
3,150 pounds and shall be capable of withstanding a 50 percent overload
(4,725 pounds total) without failure of either the anchoring equipment
or the attachment point on the manufactured home.
(g) Anchoring equipment--weatherization. Anchoring equipment exposed
to weathering shall have a resistance to weather deterioration at least
equivalent to that provided by a coating of zinc on steel of not less
than 0.30 ounces per square foot of surface coated, and in accordance
with the following:
(1) Slit or cut edges of zinc-coated steel strapping do not need to
be zinc coated.
(2) Type 1, Finish B, Grade 1 steel strapping, 1-1/4 inches wide and
0.035 inches in thickness, certified by a registered professional
engineer or architect as conforming with ASTM Standard Specification
D3953-91, Standard Specification for Strapping, Flat Steel, and Seals.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4583, Feb. 12, 1987; 59 FR 2473, Jan. 14, 1994]

Sec. 3280.307 Resistance to elements and use.

(a) Exterior coverings shall be of moisture and weather resistive
materials attached with corrosion resistant fasteners to resist wind,
snow and rain. Metal coverings and exposed metal structural members
shall be of corrosion resistant materials or shall be protected to
resist corrosion. All joints between portions of the exterior covering
shall be designed, and assembled to protect against the infiltration of
air and water, except for any designed ventilation of wall or roof
cavity.
(b) Joints between dissimilar materials and joints between exterior
coverings and frames of openings shall be protected with a compatible
sealant suitable to resist infiltration of air or water.
(c) Where adjoining materials or assemblies of materials are of such
nature that separation can occur due to expansion, contraction, wind
loads or other loads induced by erection or transportation, sealants
shall be of a type that maintains protection against infiltration or
penetration by air, moisture or vermin.

[[Page 132]]

(d) Exterior surfaces shall be sealed to resist the entrance of
rodents.

Sec. 3280.308 Formaldehyde emission controls for certain wood products.

(a) Formaldehyde emission levels. All plywood and particleboard
materials bonded with a resin system or coated with a surface finish
containing formaldehyde shall not exceed the following formaldehyde
emission levels when installed in manufactured homes:
(1) Plywood materials shall not emit formaldehyde in excess of 0.2
parts per million (ppm) as measured by the air chamber test method
specified in Sec. 3280.406.
(2) Particleboard materials shall not emit formaldehyde in excess of
0.3 ppm as measured by the air chamber test specified in Sec. 3280.406.
(b) Product certification and continuing qualification. All plywood
and particleboard materials to be installed in manufactured homes which
are bonded with a resin system or coated with a surface finish
containing formaldehyde, other than an exclusively phenol-formaldehyde
resin system or finish, shall be certified by a nationally recognized
testing laboratory as complying with paragraph (a) of this section.
(1) Separate certification shall be done for each plant where the
particleboard is produced or where the plywood or particleboard is
surface-finished.
(2) To certify plywood or particleboard, the testing laboratory
shall witness or conduct the air chamber test specified in Sec. 3280.406
on randomly selected panels initially and at least quarterly thereafter.
(3) The testing laboratory must approve a written quality control
plan for each plant where the particleboard is produced or finished or
where the plywood is finished. The quality control plan must be designed
to assure that all panels comply with paragraph (a) of this section. The
plan must establish ongoing procedures to identify increases in the
formaldehyde emission characteristics of the finished product resulting
from the following changes in production.
(i) In the case of plywood:
(A) The facility where the unfinished panels are produced is
changed;
(B) The thickness of the panels is changed so that the panels are
thinner; or
(C) The grooving pattern on the panels is changed so that the
grooves are deeper or closer together.
(ii) In the case of particleboard:
(A) The resin formulation is changed so that the formaldehyde-to-
urea ratio is increased;
(B) The amount of formaldehyde resin used is increased; or
(C) The press time is decreased.
(iii) In the case of plywood or particleboard:
(A) The finishing or top coat is changed and the new finishing or
top coat has a greater formaldehyde content; or
(B) The amount of finishing or top coat used on the panels is
increased, provided that such finishing or top coat contains
formaldehyde.
(4) The testing laboratory shall periodically visit the plant to
monitor quality control procedures to assure that all certified panels
meet the standard.
(5) To maintain its certification, plywood or particleboard must be
tested by the air chamber test specified in Sec. 3280.406 whenever one
of the following events occurs:
(i) In the case of particleboard, the resin formulation is changed
so that the formaldehyde-to-urea ratio is increased; or
(ii) In the case of particleboard or plywood, the finishing or top
coat is changed and the new finishing or top coat contains formaldehyde;
or
(iii) In the case of particleboard or plywood, the testing
laboratory determines that an air chamber test is necessary to assure
that panels comply with paragraph (a) of this section.
(6) In the event that an air chamber test measures levels of
formaldehyde from plywood or particleboard in excess of those permitted
under paragraph (a) of this section, then the tested product's
certification immediately lapses as of the date of production of the
tested panels. No panel produced on the same date as the tested panels
or on any day thereafter may be used or

[[Page 133]]

certified for use in manufactured homes.
(i) Provided, however, that a new product certification may be
obtained by testing randomly selected panels which were produced on any
day following the date of production of the tested panels. If such
panels pass the air chamber test specified in Sec. 3280.406, then the
plywood or particleboard produced on that day and subsequent days may be
used and certified for use in manufactured homes.
(ii) Provided further, that plywood or particleboard produced on the
same day as the tested panels, and panels produced on subsequent days,
if not certified pursuant to paragraph (b)(4)(i) of this section, may be
used in manufactured homes only under the following circumstances:
(A) Each panel is treated with a scavenger, sealant, or other means
of reducing formaldehyde emissions which does not adversely affect the
structural quality of the product; and
(B) Panels randomly selected from the treated panels are tested by
and pass the air chamber test specified in Sec. 3280.406.
(c) Panel identification. Each plywood and particleboard panel to be
installed in manufactured homes which is bonded or coated with a resin
system containing formaldehyde, other than an exclusively phenol-
formaldehyde resin system, shall be stamped or labeled so as to identify
the product manufacturer, date of production and/or lot number, and the
testing laboratory certifying compliance with this section.
(d) Treatment after certification. If certified plywood or
particleboard subsequently is treated with paint, varnish, or any other
substance containing formaldehyde, then the certification is no longer
valid. In such a case, each stamp or label placed on the panels pursuant
to paragraph (c) of this section must be obliterated. In addition, the
treated panels may be recertified and reidentified in accordance with
paragraphs (b) and (c) of this section.

[49 FR 32011, Aug. 9, 1984]

Sec. 3280.309 Health Notice on formaldehyde emissions.

(a) Each manufactured home shall have a Health Notice on
formaldehyde emissions prominently displayed in a temporary manner in
the kitchen (i.e., countertop or exposed cabinet face). The Notice shall
read as follows:

Important Health Notice

Some of the building materials used in this home emit formaldehyde.
Eye, nose, and throat irritation, headache, nausea, and a variety of
asthma-like symptoms, including shortness of breath, have been reported
as a result of formaldehyde exposure. Elderly persons and young
children, as well as anyone with a history of asthma, allergies, or lung
problems, may be at greater risk. Research is continuing on the possible
long-term effects of exposure to formaldehyde.
Reduced ventilation resulting from energy efficiency standards may
allow formaldehyde and other contaminants to accumulate in the indoor
air. Additional ventilation to dilute the indoor air may be obtained
from a passive or mechanical ventilation system offered by the
manufacturer. Consult your dealer for information about the ventilation
options offered with this home.
High indoor temperatures and humidity raise formaldehyde levels.
When a home is to be located in areas subject to extreme summer
temperatures, an air-conditioning system can be used to control indoor
temperature levels. Check the comfort cooling certificate to determine
if this home has been equipped or designed for the installation of an
air-conditioning system.
If you have any questions regarding the health effects of
formaldehyde, consult your doctor or local health department.

(b) The Notice shall be legible and typed using letters at least \1/
4\ inch in size. The title shall be typed using letters at least \3/4\
inch in size.
(c) The Notice shall not be removed by any party until the entire
sales transaction has been completed (refer to part 3282--Manufactured
Home Procedural and Enforcement Regulations for provisions regarding a
sales transaction).
(d) A copy of the Notice shall be included in the Consumer Manual
(refer to part 3283--Manufactured Home Consumer Manual Requirements).

[49 FR 32012, Aug. 9, 1984, as amended at 54 FR 46049, Nov. 1, 1989; 58
FR 55007, Oct. 25, 1993]

[[Page 134]]

Subpart E--Testing

Sec. 3280.401 Structural load tests.

Every structural assembly tested shall be capable of meeting the
Proof Load Test or the Ultimate Load Test as follows:
(a) Proof load tests. Every structural assembly tested shall be
capable of sustaining its dead load plus superimposed live loads equal
to 1.75 times the required live loads for a period of 12 hours without
failure. Tests shall be conducted with loads applied and deflections
recorded in \1/4\ design live load increments at 10-minute intervals
until 1.25 times design live load plus dead load has been reached.
Additional load shall then be applied continuously until 1.75 times
design live load plus dead load has been reached. Assembly failure shall
be considered as design live load deflection (or residual deflection
measured 12 hours after live load removal) which is greater than the
limits set in Sec. 3280.305(d), rupture, fracture, or excessive
yielding. An assembly to be tested shall be of the minimum quality of
materials and workmanship of the production. Each test assembly,
component or subassembly shall be identified as to type and quality or
grade of material. All assemblies, components or subassemblies
qualifying under this section shall be subject to a continuing
qualification testing program acceptable to the Department.
(b) Ultimate load tests. Ultimate load tests shall be performed on a
minimum of three assemblies or components to generally evaluate the
structural design. Every structural assembly or component tested shall
be capable of sustaining its total dead load plus the design live load
increased by a factor of safety of at least 2.5. A factor of safety
greater than 2.5 shall be used when required by an applicable reference
standard in Sec. 3280.304(b)(1). Tests shall be conducted with loads
applied and deflections recorded in \1/4\ design live load increments at
10-minute intervals until 1.25 times design live load plus dead load has
been reached. Additional loading shall then be applied continuously
until failure occurs or the total of the factor of safety times the
design live load plus the dead load is reached. Assembly failure shall
be considered as design live load deflection greater than the limits set
in Sec. 3208.305(d), rupture, fracture, or excessive yielding.
Assemblies to be tested shall be representative of average quality or
materials and workmanship of the production. Each test assembly,
component, or sub-assembly shall be identified as to type and quality or
grade of material. All assemblies, components, or sub-assemblies
qualifying under this section shall be subject to a periodic
qualification testing program acceptable to the Department.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55007, Oct. 25, 1993]

Sec. 3280.402 Test procedure for roof trusses.

(a) Roof load tests. The following is an acceptable test procedure,
consistent with the provisions of Sec. 3280.401, for roof trusses that
are supported at the ends and support design loads. Where roof trusses
act as support for other members, act as cantilevers, or support
concentrated loads, they shall be tested accordingly.
(b) General. Trusses may be tested in pairs or singly in a suitable
test facility. When tested singly, simulated lateral support of the test
assembly may be provided, but in no case shall this lateral support
exceed that which is specified for the completed manufactured home. When
tested in pairs, the trusses shall be spaced at the design spacing and
shall be mounted on solid support accurately positioned to give the
required clear span distance (L) as specified in the design. The top and
bottom chords shall be braced and covered with the material, with
connections or method of attachment, as specified by the completed
manufactured home.
(1) As an alternate test procedure, the top chord may be sheathed
with \1/4\ inch by 12 inch plywood strips. The plywood strips shall be
at least long enough to cover the top chords of the trusses at the
designated design truss spacing. Adjacent plywood strips must be
separated by at least \1/8\ inch. The plywood strip shall be nailed with
4d nails or equivalent staples not closer than 8 inches on center along
the top

[[Page 135]]

chord. The bottom chords of the adjacent trusses may be either:
(i) Unbraced,
(ii) Laterally braced together (not cross braced) with 1" x 2"
stripping not closer than 24 inches on center nailed with only one 6d
nail at each truss, or
(iii) Covered with the material, with connections or methods of
attachment, as specified for the completed manufactured home.
(2) Truss deflections will be measured relative to a taut wire
running over the support and weighted at the end to insure constant
tension or other approved methods. Deflections will be measured at the
two quarter points and at midspan. Loading shall be applied to the top
chord through a suitable hydraulic, pneumatic, or mechanical system,
masonry units, or weights to simulate design loads. Load units for
uniformly distributed loads shall be separated so that arch action does
not occur, and shall be spaced not greater than 12 inches on center so
as to simulate uniform loading.
(c) Nondestructive test procedure--(1) Dead load plus live load. (i)
Noting figure A-1, measure and record initial elevation of the truss in
test position at no load.

[[Page 136]]

[GRAPHIC] [TIFF OMITTED] TC17OC91.008

(ii) Apply load units to the top chord of the truss equal to the
full dead load of roof and ceiling. Measure and record deflections.
(iii) Maintaining the dead load, add live load in approximate \1/4\
design live load increments. Measure the deflections after each loading
increment.

[[Page 137]]

Apply incremental loads at a uniform rate such that approximately one-
half hour is required to establish the total design load condition.
Measure and record the deflections five minutes after loads have been
applied. The maximum deflection due to design live load (deflection
measured in step (iii) minus step (ii)) shall not exceed L/180, where L
is a clear span measured in the same units.
(iv) Continue to load truss to dead load plus 1.75 times the design
live load. Maintain this loading for 12 hours and inspect the truss for
failure.
(v) Remove the total superimposed live load. Trusses not recovering
to at least the L/180 position within 12 hours shall be considered as
failing.
(2) Uplift loads. This test shall only be required for truss designs
which may be critical under uplift load conditions.
(i) Measure and record initial elevation of the truss in an inverted
test position at no load. Bottom chord of the truss shall be mounted in
the horizontal position.
(ii) Apply the uplift load as stated in Sec. 3280.305(c) to the
bottom chord of the truss. Measure and record the deflections 5 minutes
after the load has been applied.
(iii) Continue to load the truss to 1.75 times the design uplift
load. Maintain this load for 3 hours and inspect the truss for failure.
(iv) Remove applied loads and within three hours the truss must
recover to at least L/180 position, where L is a clear span measured in
the same units.
(d) Destructive test procedure. (1) Destructive tests shall be
performed on three trusses to generally evaluate the truss design.
(2) Noting figure A-1, apply the load units to the top chord of the
truss assembly equal to full dead load of roof and ceiling. Measure and
record deflections. Then apply load and record deflections in \1/4\
design live load increments at 10-minute intervals until 1.25 times
design live load plus dead load has been reached.
(3) Additional loading shall then be applied continuously until
failure occurs or the factor of safety times the design live load plus
the dead load is reached.
(4) Assembly failure shall be considered as design live load
deflection greater than the limits set in Sec. 3280.305(d), rupture,
fracture, or excessive yielding.
(5) The assembly shall be capable of sustaining the dead load plus
the applicable factor of safety times the design live load (the
applicable factor of safety for wood trusses shall be taken as 2.50).
(e) Trusses qualifying under the nondestructive test procedure.
Tests Sec. 3208.402(c) (1) and (2) (when required), shall be subject to
a continuing qualification testing program acceptable to the Department.
Trusses qualifying under the destructive test procedures, Tests
Sec. 3280.402 (c)(2) (when required), and (d), shall be subject to
periodic tests only.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 961, Jan. 4, 1977.
Redesignated at 44 FR 20679. Apr. 6, 1979, as amended at 58 FR 55008,
Oct. 25, 1993]

Sec. 3280.403 Standard for windows and sliding glass doors used in manufactured homes.

(a) Scope. This section sets the requirements for prime windows and
sliding glass doors except for windows used in entry doors. Windows so
mounted are components of the door and thus are excluded from this
standard.
(b) Standard. All primary windows and sliding glass doors shall
comply with AAMA Standard 1701.2-1985, Primary Window and Sliding Glass
Door Voluntary Standard for Utilization in Manufactured Housing, except
that by January 17, 1995, the exterior and interior pressure tests shall
be conducted at the design wind loads required for components and
cladding specified in Sec. 3280.305(c)(1).
(c) Installation. All primary windows and sliding glass doors shall
be installed in a manner which allows proper operation and provides
protection against the elements (see Sec. 3280.307).
(d) Glass. (1) Safety glazing materials, where used, shall meet ANSI
Z97.1-1984, ``Safety Performance Specifications and Methods of Test for
Safety Glazing Materials Used in Buildings.''

[[Page 138]]

(2) Sealed insulating glass, where used, shall meet all performance
requirements for Class C in accordance with ASTM E-774-92, Standard
Specification for Sealed Insulating Glass Units. The sealing system
shall be qualified in accordance with ASTM E-773-88 Standard Test
Methods for Seal Durability of Sealed Insulating Glass Units. Each glass
unit shall be permanently identified with the name of the insulating
glass manufacturer.
(e) Certification. All primary windows and sliding glass doors to be
installed in manufactured homes shall be certified as complying with
AAMA Standard 1701.2-1985. As of January 17, 1995, this certification
must be based on tests conducted at the design wind loads specified in
Sec. 3280.305(c)(1).
(1) All such windows and doors shall show evidence of certification
by affixing a quality certification label to the product in accordance
with ANSI Z34.1-1987, ``For Certification-Third-Party Certification
Program.''
(2) In determining certifiability of the products, an independent
quality assurance agency shall conduct preproduction specimen tests in
accordance with AAMA 1702.2-1985. Further, such agency shall inspect the
product manufacturer's facility at least twice per year.
(f) Protection of primary window and sliding glass door openings in
high wind areas. For homes designed to be located in Wind Zones II and
III, manufacturers shall design exterior walls surrounding the primary
window and sliding glass door openings to allow for the installation of
shutters or other protective covers, such as plywood, to cover these
openings. Although not required, the Department encourages manufacturers
to provide the shutters or protective covers and to install receiving
devices, sleeves, or anchors for fasteners to be used to secure the
shutters or protective covers to the exterior walls. If the manufacturer
does not provide shutters or other protective covers to cover these
openings, the manufacturer must provide to the homeowner instructions
for at least one method of protecting primary window and sliding glass
door openings. This method must be capable of resisting the design wind
pressures specified in Sec. 3280.305 without taking the home out of
conformance with the standards in this part. These instructions must be
included in the printed instructions that accompany each manufactured
home. The instructions shall also indicate whether receiving devices,
sleeves, or anchors, for fasteners to be used to secure the shutters or
protective covers to the exterior walls, have been installed or provided
by the manufacturer.

[52 FR 4583, Feb. 12, 1987, as amended at 52 FR 35543, Sept. 22, 1987;
58 FR 55009, Oct. 25, 1993; 59 FR 2474, Jan. 14, 1994]

Sec. 3280.404 Standard for egress windows and devices for use in manufactured homes.

(a) Scope and purpose. The purpose of this section is to establish
the requirements for the design, construction, and installation of
windows and approved devices intended to be used as an emergency exit
during conditions encountered in a fire or similar disaster.
(b) Performance. Egress windows including auxiliary frame and seals,
if any, shall meet all requirements of AAMA Standard 1701.2-1985,
Primary Window and Sliding Glass Door Voluntary Standard for Utilization
in Manufactured Housing and AAMA Standard 1704-1985, Voluntary Standard
Egress Window Systems for Utilization in Manufactured--Housing, except
that by January 17, 1995, the exterior and interior pressure tests for
components and cladding shall be conducted at the design wind loads
required by Sec. 3280.305(c)(1).
(c) Installation. (1) The installation of egress windows or devices
shall be installed in a manner which allows for proper operation and
provides protection against the elements. (See Sec. 3280.307.)
(2) An operational check of each installed egress window or device
shall be made at the manufactured home factory. All egress windows and
devices shall be openable to the minimum required dimension without
binding or requiring the use of tools. Any window or device failing this
check shall be repaired or replaced. A repaired window shall conform to
its certification. Any repaired or replaced window or device shall pass
the operational check.

[[Page 139]]

(d) Operating instructions. Operating instructions shall be affixed
to each egress window and device and carry the legend ``Do Not Remove.''
(e) Certification of egress windows and devices. Egress windows and
devices shall be listed in accordance with the procedures and
requirements of AAMA Standard 1704-1985. As of January 17, 1995, this
certification must be based on tests conducted at the design wind loads
specified in Sec. 3280.305(c)(1).
(f) Protection of egress window openings in high wind areas. For
homes designed to be located in Wind Zones II and III, manufacturers
shall design exterior walls surrounding the egress window openings to
allow for the installation of shutters or other protective covers, such
as plywood, to cover these openings. Although not required, the
Department encourages manufacturers to provide the shutters or
protective covers and to install receiving devices, sleeves, or anchors
for fasteners to be used to secure the shutters or protective covers to
the exterior walls. If the manufacturer does not provide shutters or
other protective covers to cover these openings, the manufacturer must
provide to the homeowner instructions for at least one method of
protecting egress window openings. This method must be capable of
resisting the design wind pressures specified in Sec. 3280.305 without
taking the home out of conformance with the standards in this part.
These instructions must be included in the printed instructions that
accompany each manufactured home. The instructions shall also indicate
whether receiving devices, sleeves, or anchors, for fasteners to be used
to secure the shutters or protective covers to the exterior walls, have
been installed or provided by the manufacturer.

[52 FR 4583, Feb. 12, 1987, as amended at 59 FR 2474, Jan. 14, 1994]

Sec. 3280.405 Standard for swinging exterior passage doors for use in manufactured homes.

(a) Introduction. This standard applies to all exterior passage door
units, excluding sliding doors and doors used for access to utilities
and compartments. This standard applies only to the door frame
consisting of jambs, head and sill and the attached door or doors.
(b) Performance requirements. The design and construction of
exterior door units shall meet all requirements of AAMA 1702.2-1985,
Swinging Exterior Passage Doors Voluntary Standard for Utilization in
Manufactured--Housing.
(c) Materials and methods. Any material or method of construction
shall conform to the performance requirements as outlined in paragraph
(b) of this section. Wood materials or wood based materials shall also
conform to the following:
(1) Wood. Doors shall conform to the type 1 requirements of ANSI/
NWWDA I.S.1-87, Wood Flush Doors.
(2) Plywood. Plywood shall be exterior type and preservative treated
in accordance with NWWDA I.S.4-81, Water Repellent Preservative Non-
Pressure Treatment for Millwork.
(d) Exterior doors. All swinging exterior doors shall be installed
in a manner which allows proper operation and provides protection
against the elements (see Sec. 3280.307).
(e) Certification. All swinging exterior doors to be installed in
manufactured homes shall be certified as complying with AAMA Standard
1702.2-1985.
(1) All such doors shall show evidence of certification by affixing
a quality certification label to the product in accordance with ANSI
Z34.1-1982, ``For Certification-Third-Party Certification Program.''
(2) In determining certifiability of the products, an independent
quality assurance agency shall conduct preproduction specimen test in
accordance with AAMA 1701.2-1985. Further, such agency shall inspect the
product manufacturer's facility at least twice per year.
(f) Protection of exterior doors in high wind areas. For homes
designed to be located in Wind Zones II and III, manufacturers shall
design exterior walls surrounding the exterior door openings to allow
for the installation of shutters or other protective covers, such as
plywood, to cover these openings. Although not required, the Department
encourages manufacturers to provide the shutters or protective covers
and to install receiving devices, sleeves, or

[[Page 140]]

anchors for fasteners to be used to secure the shutters or protective
covers to the exterior walls. If the manufacturer does not provide
shutters or other protective covers to cover these openings, the
manufacturer must provide to the homeowner instructions for at least one
method of protecting exterior door openings. This method must be capable
of resisting the design wind pressures specified in Sec. 3280.305
without taking the home out of conformance with the standards in this
part. These instructions must be included in the printed instructions
that accompany each manufactured home. The instructions shall also
indicate whether receiving devices, sleeves, or anchors, for fasteners
to be used to secure the shutters or protective covers to the exterior
walls, have been installed or provided by the manufacturer.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4583, Feb. 12, 1987; 52 FR 35543, Sept. 22, 1987; 58
FR 55009, Oct. 25, 1993; 59 FR 2474, Jan. 14, 1994]

Sec. 3280.406 Air chamber test method for certification and qualification of formaldehyde emission levels.

(a) Preconditioning. Preconditioning of plywood or particleboard
panels for air chamber tests shall be initiated as soon as practicable
but not in excess of 30 days after the plywood or particleboard is
produced or surface-finished, whichever is later, using randomly
selected panels.
(1) If preconditioning is to be initiated more than two days after
the plywood or particleboard is produced or surface-finished, whichever
is later, the panels must be dead-stacked or air-tight wrapped until
preconditioning is initiated.
(2) Panels selected for testing in the air chamber shall not be
taken from the top or botton of the stack.
(b) Testing. Testing shall be conducted in accordance with the
Standard Test Method for Determining Formaldehyde Levels from Wood
Products Under Defined Test Conditions Using a Large Chamber, ASTM E-
1333-90, with the following exceptions:
(1) The chamber shall be operated indoors.
(2) Plywood and particleboard panels shall be individually tested in
accordance with the following loading ratios:
(i) Plywood--0.29 Ft2/Ft3, and
(ii) Particleboard--0.13 Ft2/Ft3.
(3) Temperature to be maintained inside the chamber shall be 77 deg.
plus or minus 2 deg. F.
(4) The test concentration (C) shall be standardized to a level
(CO) at a temperature (tO) of 77 deg. F and 50%
relative humidity (HO) by the following formula:

C = CO x [1 + Ax (H - HO)] x
e^{-R(1 / t - 1 / t O)}

where:

C = Test formaldehyde concentration
CO = Standardized formaldehyde concentration
e = Natural log base
R = Coefficient of temperature (9799)
t = Actual test condition temperature (^O K)
tO = Standardized temperature (^O K)
A = Coefficient of humidity (0.0175)
H = Actual relative humidity (%)
HO = Standardized relative humidity (%)

The standardized level (CO) is the concentration used to
determine compliance with Sec. 3280.308(a).

(5) The air chamber shall be inspected and recalibrated at least
annually to insure its proper operation under test conditions.

[49 FR 32012, Aug. 9, 1984, as amended at 58 FR 55009, Oct. 25, 1993]

Subpart F--Thermal Protection

Sec. 3280.501 Scope.

This subpart sets forth the requirements for condensation control,
air infiltration, thermal insulation and certification for heating and
comfort cooling.

Sec. 3280.502 Definitions.

(a) The following definitions are applicable to subpart F only:
(1) Pressure envelope means that primary air barrier surrounding the
living space which serves to limit air leakage. In construction using
ventilated cavities, the pressure envelope is the interior skin.
(2) Thermal envelope area means the sum of the surface areas of
outside walls, ceiling and floor, including all openings. The wall area
is measured by

[[Page 141]]

multiplying outside wall lengths by the inside wall height from floor to
ceiling. The floor and ceiling areas are considered as horizontal
surfaces using exterior width and length.

Sec. 3280.503 Materials.

Materials used for insulation shall be of proven effectiveness and
adequate durability to assure that required design conditions concerning
thermal transmission are attained.

Sec. 3280.504 Condensation control and installation of vapor retarders.

(a) Ceiling vapor retarders. (1) In Uo Value Zones 2 and 3, ceilings
shall have a vapor retarder with a permanence of not greater than 1 perm
(as measured by ASTM E-96-93 Standard Test Methods for Water Vapor
Transmission of Materials) installed on the living space side of the
roof cavity.
(2) For manufactured homes designed for Uo Value Zone 1, the vapor
retarder may be omitted.
(b) Exterior walls. (1) Exterior walls shall have a vapor barrier
not greater than 1 perm (dry cup method) installed on the living space
side of the wall, or
(2) Unventilated wall cavities shall have an external covering and/
or sheathing which forms the pressure envelope. The covering and/or
sheathing shall have a combined permeance of not less than 5.0 perms. In
the absence of test data, combined permeance may be computed using the
formula: PTotal=(1/[(1/P1)+(1/P2)])

where P1 and P2 are the permeance values of the
exterior covering and sheathing in perms.

Formed exterior siding applied in sections with joints not caulked or
sealed shall not be considered to restrict water vapor transmission, or
(3) Wall cavities shall be constructed so that ventilation is
provided to dissipate any condensation occurring in these cavities.
(c) Attic or roof ventilation. (1) Attic and roof cavities shall be
vented in accordance with one of the following:
(i) A minimum free ventilation area of not less than 1/300 of the
attic or roof cavity floor area. At least 50 percent of the required
free ventilation area shall be provided by ventilators located in the
upper portion of the space to be ventilated. At least 40 percent shall
be provided by eave, soffit or low gable vents. The location and spacing
of the vent openings and ventilators shall provide cross-ventilation to
the entire attic or roof cavity space. A clear air passage space having
a minimum height of 1 inch shall be provided between the top of the
insulation and the roof sheathing or roof covering. Baffles or other
means shall be provided where needed to insure the 1 inch height of the
clear air passage space is maintained.
(ii) A mechanical attic or roof ventilation system may be installed
instead of providing the free ventilation area when the mechanical
system provides a minimum air change rate of 0.02 cubic feet per minute
(cfm) per sq. ft. of attic floor area. Intake and exhaust vents shall be
located so as to provide air movement throughout space.
(2) Single section manufactured homes constructed with metal roofs
and having no sheathing or underlayment installed, are not required to
be provided with attic or roof cavity ventilation provided that the air
leakage paths from the living space to the roof cavity created by
electrical outlets, electrical junctions, electrical cable penetrations,
plumbing penetrations, flue pipe penetrations and exhaust vent
penetrations are sealed.
(3) Parallel membrane roof section of a closed cell type
construction are not required to be ventilated.
(4) The vents provided for ventilating attics and roof cavities
shall be designed to resist entry of rain and insects.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55009, Oct. 25, 1993]

Sec. 3280.505 Air infiltration.

(a) Envelope air infiltration. The opaque envelope shall be designed
and constructed to limit air infiltration to the living area of the
home. Any design, material, method or combination thereof which
accomplishes this goal may be used. The goal of the infiltration control
criteria is to reduce heat loss/heat gain due to infiltration as much as
possible without impinging on

[[Page 142]]

health and comfort and within the limits of reasonable economics.
(1) Envelope penetrations. Plumbing, mechanical and electrical
penetrations of the pressure envelope not exempted by this part, and
installations of window and door frames shall be constructed or treated
to limit air infiltration. Penetrations of the pressure envelope made by
electrical equipment, other than distribution panel boards and cable and
conduit penetrations, are exempt from this requirement. Cable
penetrations through outlet boxes are considered exempt.
(2) Joints between major envelope elements. Joints not designed to
limit air infiltration between wall-to-wall, wall-to-ceiling and wall-
to-floor connections shall be caulked or otherwise sealed. When walls
are constructed to form a pressure envelope on the outside of the wall
cavity, they are deemed to meet this requirement.

Sec. 3280.506 Heat loss/heat gain.

The manufactured home heat loss/heat gain shall be determined by
methods outlined in Secs. 3280.508 and 3280.509. The Uo (Coefficient of
heat transmission) value zone for which the manufactured home is
acceptable and the lowest outdoor temperature to which the installed
heating equipment will maintain a temperature of 70 F shall be certified
as specified in Sec. 3280.510 of this subpart. The Uo value zone shall
be determined from the map in figure 506.

[[Page 143]]

[GRAPHIC] [TIFF OMITTED] TC17OC91.005

(a) Coefficient of heat transmission. The overall coefficient of
heat transmission (Uo) of the manufactured home for the respective zones
and an indoor design temperature of 70 F, including internal and
external ducts, and excluding infiltration, ventilation and condensation
control, shall not exceed

[[Page 144]]

the Btu/(hr.) (sq. ft.) (F) of the manufactured home envelope are as
tabulated below:

------------------------------------------------------------------------
Maximum coefficient of heat
Uo value zone transmission
------------------------------------------------------------------------
1........................................ 0.116 Btu/(hr.) (sq. ft.)
(F).
2........................................ 0.096 Btu/(hr.) (sq. ft.)
(F).
3........................................ 0.079 Btu/(hr.) (sq. ft.)
(F).
------------------------------------------------------------------------

(b) To assure uniform heat transmission in manufactured homes,
cavities in exterior walls, floors, and ceilings shall be provided with
thermal insulation.
(c) Manufactured homes designed for Uo Value Zone 3 shall be factory
equipped with storm windows or insulating glass.

[58 FR 55009, Oct. 25, 1993; 59 FR 15113, Mar. 31, 1994]

Sec. 3280.507 Comfort heat gain.

Information necessary to calculate the home cooling load shall be
provided as specified in this part.
(a) Transmission heat gains. Homes complying with this section shall
meet the minimum heat loss transmission coefficients specified in
Sec. 3280.506(a).

Sec. 3280.508 Heat loss, heat gain and cooling load calculations.

(a) Information, values and data necessary for heat loss and heat
gain determinations shall be taken from the 1989 ASHRAE Handbook of
Fundamentals, chapters 20 through 27. The following portions of those
chapters are not applicable:

21.1 Steel Frame Construction
21.2 Masonry Construction
21.3 Floor Systems
21.14 Pipes
21.16 Tanks, Vessels and Equipment
21.17 Refrigerated Rooms and Buildings
22.15 Mechanical and Industrial Systems
23.13 Commercial Building Envelope Leakage
25.4 Calculation of Heat Loss from Crawl Spaces

(b) The calculation of the manufactured home's transmission heat
loss coefficient (Uo) shall be in accordance with the fundamental
principals of the 1989 ASHRAE Handbook of Fundamentals and, at a
minimum, shall address all the heat loss or heat gain considerations in
a manner consistent with the calculation procedures provided in the
document Overall U-values and Heating/Cooling Loads-Manufactured Homes--
February 1992-PNL 8006, HUD User No. 0005945.
(c) Areas where the insulation does not fully cover a surface or is
compressed shall be accounted for in the U-calculation (see
Sec. 3280.506). The effect of framing on the U-value must be included in
the Uo calculation. Other low-R-value heat-flow paths (``thermal
shorts'') shall be explicitly accounted for in the calculation of the
transmission heat loss coefficient if in the aggregate all types of low-
R-value paths amount to more than 1% of the total exterior surface area.
Areas are considered low-R-value heat-flow paths if:
(1) They separate conditioned and unconditioned space; and
(2) They are not insulated to a level that is at least one-half the
nominal insulation level of the surrounding building component.
(d) High efficiency heating and cooling equipment credit. The
calculated transmission heat loss coefficient (Uo) used for meeting the
requirement in Sec. 3280.506(a) may be adjusted for heating and cooling
equipment above that required by the National Appliance Energy
Conservation Act of 1987 (NAECA) by applying the following formula:

Uo adjusted = Uo standard x [1+(0.6) (heating efficiency increase
factor)+(cooling multiplier) (cooling efficiency increase factor)]

where:
Uo standard = Maximum Uo for Uo Zone required by Sec. 3280.506(a)
Uo adjusted = Maximum Uo standard adjusted for high efficiency HVAC
equipment
Heating efficiency increase factor = The increase factor in heating
equipment efficiency measured by the Annual Fuel Utilization Efficiency
(AFUE), or the Heating Seasonal Performance Factor (HSPF) for heat
pumps, above that required by NAECA (indicated as ``NAECA'' in formula).
The formula is heating efficiency increase factor = AFUE (HSPF) home -
AFUE (or HSPF) NAECA divided by AFUE (HSPF) NAECA.
Cooling efficiency increase factor = the increase factor in the cooling
equipment efficiency measured by the Seasonal Energy Efficiency Ratio
(SEER) above that required by NAECA.

[[Page 145]]

The formula being cooling equipment=SEER home--SEER NAECA divided by
SEER NAECA.

The cooling multiplier for the Uo Zone is from the following table:

------------------------------------------------------------------------
Uo zone Cooling multiplier (Cm)
------------------------------------------------------------------------
1........................................ 0.60 (Florida only).
1........................................ 0.20 (All other locations).
2........................................ 0.07.
3........................................ 0.03.
------------------------------------------------------------------------

(e) U-values for any glazing (windows, skylights, and the glazed
portions of any door) shall be based on tests using American
Architectural Manufacturers Association (AAMA) 1503.1-1988, Voluntary
Test Method for Thermal Transmittance and Condensation Resistance of
Windows, Doors and Glazed Wall Sections. In the absence of tests,
manufacturers shall use the residential window U values contained in
table 13 in chapter 27, the 1989 ASHRAE Handbook of Fundamentals. In the
event that the classification of the window type is indeterminate, the
manufacturer shall use the classification which gives the higher U
value. For the purpose of calculating Uo values, storm windows shall be
treated as an additional pane.
(f) Annual energy used based compliance. As an alternative, homes
may demonstrate compliance with the annual energy used implicit in the
coefficient of heat transmission (Uo) requirement. The annual energy use
determination must be based on generally accepted engineering practices.
The general requirement is to demonstrate that the home seeking
compliance approval has a projected annual energy use, including both
heating and cooling, less than or equal to a similar ``base case'' home
that meets the standard. The energy use for both homes must be
calculated based on the same assumptions; including assuming the same
dimensions for all boundaries between conditioned and unconditioned
spaces, site characteristics, usage patterns and climate.

[58 FR 55011, Oct. 25, 1993]

Sec. 3280.509 Criteria in absence of specific data.

In the absence of specific data, for purposes of heat-loss/gain
calculation, the following criteria shall be used:
(a) Infiltration heat loss. In the absence of measured infiltration
heat loss data, the following formula shall be used to calculate heat
loss due to infiltration and intermittently operated fans exhausting to
the outdoors. The perimeter calculation shall be based on the dimensions
of the pressure envelope.

Infiltration Heat-Loss=0.7 (T) (ft. of perimeter), BTU/hr.

where: T=70 minus the heating system capacity certification temperature
stipulated in the Heating Certificate, in F.

(b) Framing areas.

Wall..................................... 15 percent of wall area less
windows and doors.
Floor and Ceiling........................ 10 percent of the area.

(c) Insulation compression. Insulation compressed to less than
nominal thickness shall have its nominal R-values reduced for that area
which is compressed in accordance with the following graph:

[[Page 146]]

[GRAPHIC] [TIFF OMITTED] TC17OC91.006

When insulation is installed over the framing members the thermal
performance of the insulation is reduced due to compression at the
framing members. The Resistance value of the insulation between the
framing members is reduced by 12.5 percent for framing members 16" O.C.,
8.5 percent for framing members 24" O.C., and 4 percent for framing
members 48" O.C.
(d) Air supply ducts within floor cavity. Air supply ducts located
within a floor cavity shall be assumed to be heating or cooling the
floor cavity to living space temperatures unless the duct is
structurally isolated by the framing system or thermally insulated from
the rest of the floor cavity with a thermal insulation at least equal to
R-4.
(e) Air supply ducts within ceiling cavity. Where supply ducts are
located in ceiling cavities, the influence of the duct on cavity
temperatures shall be considered in calculating envelope heat loss or
heat gain.
(f) The supply duct loss (and/or heat gain where applicable--See
Sec. 3280.511) shall be calculated using the actual duct surface area
and the actual thickness of insulation between the duct and outside of
the manufactured home. If there is an air space of at least \1/2\ inch
between the duct and the insulation, heat loss/gain need not be
calculated if the cavity in which the duct is located is assumed to be
at living space temperature. The average temperature inside the supply
duct, including ducts installed outside the manufactured home, shall be
assumed to be 130 F for purposes of calculation of heat loss and 60 F
for heat gain.
(g) Return air cavities. Cavities used as return air plenums shall
be considered to be at living space temperature.

Sec. 3280.510 Heat loss certificate.

The manufactured home manufacturer shall permanently affix the
following ``Certificate'' to an interior surface of the home that is
readily visible to the homeowner. The ``Certificate'' shall specify the
following:
(a) Heating zone certification. The design zone at which the
manufactured home heat loss complies with Sec. 3280.506(a).
(b) Outdoor certification temperature. The lowest outdoor
temperature at which the installed heating equipment will maintain a
70 deg.F temperature inside the home without storm sash or insulating
glass for Zones 1 and 2, and with storm sash or insulating glass for
Zone 3 and complying with Sec. 3280.508 and Sec. 3280.509.
(c) Operating economy certification temperature. The temperature to
be specified for operating economy and energy conservation shall be
20 deg.F or 30% of the design temperature difference, whichever is
greater, added to the temperature specified as the heating system
capacity certification temperature without storm windows or insulating
glass in Zones 1 and 2 and with storm windows or insulating glass in
Zone 3. Design temperature difference is 70 deg.

[[Page 147]]

minus the heating system capacity certification temperature in degrees
Fahrenheit.

HEATING CERTIFICATE

Home Manufacturer_______________________________________________________
Plant Location__________________________________________________________
Home Model______________________________________________________________

(Include Uo Value Zone Map)

This manufactured home has been thermally insulated to conform with
the requirements of the Federal Manufactured Home Construction and
Safety Standards for all locations within Uo Value Zone ____.

Heating Equipment Manufacturer__________________________________________
Heating Equipment Model_________________________________________________

The above heating equipment has the capacity to maintain an average
70F temperature in this home at outdoor temperatures of [see paragraph
(b) of this section] F. To maximize furnace operating economy and to
conserve energy, it is recommended that this home be installed where the
outdoor winter design temperature (97 1/2%) is not higher than [see
paragraph (c) of this section] F degrees Fahrenheit.
The above information has been calculated assuming a maximum wind
velocity of 15 MPH at standard atmospheric pressure.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55011, Oct. 25, 1993]

Sec. 3280.511 Comfort cooling certificate and information.

(a) The manufactured home manufacturer shall permanently affix a
``Comfort Cooling Certificate'' to an interior surface of the home that
is readily visible to the home owner. This certificate may be combined
with the heating certificate required in Sec. 3280.510. The manufacturer
shall comply with one of the following three alternatives in providing
the certificate and additional information concerning the cooling of the
manufactured home:
(1) Alternative I. If a central air conditioning system is provided
by the home manufacturer, the heat gain calculation necessary to
properly size the air conditioning equipment shall be in accordance with
procedures outlined in chapter 22 of the 1989 ASHRAE Handbook of
Fundamentals, with an assumed location and orientation. The following
shall be supplied in the Comfort Cooling Certificate:

Air Conditioner Manufacturer____________________________________________
Air Conditioner Model___________________________________________________

Certified Capacity ______ BTU/Hr. in accordance with the appropriate
Air Conditioning and Refrigeration Institute Standards
The central air conditioning system provided with this home has been
sized, assuming an orientation of the front (hitch) end of the home
facing ______ and is designed on the basis of a 75 deg.F indoor
temperature and an outdoor temperature of __ deg.F dry bulb and __
deg.F wet bulb.

Example Alternate I

COMFORT COOLING CERTIFICATE

Manufactured Home Mfg___________________________________________________
Plant Location__________________________________________________________
Manufactured Home Model_________________________________________________
Air Conditioner Manufacturer____________________________________________

Certified Capacity ______ BTU/Hr. in accordance with the appropriate
Air Conditioning and Refrigeration Institute Standards.
The central air conditioning system provided with this home has been
sized assuming an orientation of the front (hitch end) of the home
facing ______. On this basis, the system is designed to maintain an
indoor temperature of 75 deg.F when outdoor temperatures are __ deg.F
dry bulb and __ deg.F wet bulb.
The temperature to which this home can be cooled will change
depending upon the amount of exposure of the windows to the sun's
radiant heat. Therefore, the home's heat gains will vary dependent upon
its orientation to the sun and any permanent shading provided.
Information concerning the calculation of cooling loads at various
locations, window exposures and shadings are provided in chapter 22 of
the 1989 edition of the ASHRAE Handbook of Fundamentals.

(2) Alternative 2. For each home suitable for a central air cooling
system, the manufacturer shall provide the following statement: ``This
air distribution system of this home is suitable for the installation of
a central air conditioning system.''

Example Alternate 2

Comfort Cooling Certificate

Manufactured Home Manufacturer__________________________________________
Plant Location__________________________________________________________
Manufactured Home Model_________________________________________________
This air distribution system of this home is suitable for the
installation of central air conditioning.
The supply air distribution system installed in this home is sized
for Manufactured Home Central Air Conditioning System of up to ______
B.T.U./Hr. rated capacity which are certified in accordance with the
appropriate Air Conditioning and Refrigeration Institute Standards. When
the air circulators of such air conditioners are rated

[[Page 148]]

at 0.3 inch water column static pressure or greater for the cooling air
delivered to the manufactured home supply air duct system.
Information necessary to calculate cooling loads at various
locations and orientations is provided in the special comfort cooling
information provided with this manufactured home.

(3) Alternative 3. If the manufactured home is not equipped with an
air supply duct system, or if the manufacturer elects not to designate
the home as being suitable for the installation of a central air
conditioning system, the manufacturer shall provide the following
statement: ``This air distribution system of this home has not been
designed in anticipation of its use with a central air conditioning
system.''

Example Alternate 3

Comfort Cooling Certificate

Manufactured Home Mfg___________________________________________________
Plant Location__________________________________________________________
Manufactured Home Model_________________________________________________
The air distribution system of this home has not been designed in
anticipation of its use with a central air conditioning system.

(b) For each home designated as suitable for central air
conditioning the manufacturer shall provide the maximum central
manufactured home air conditioning capacity certified in accordance with
the ARI Standard 210/240-89 Unitary Air-Conditioning and Air-Source Heat
Pump Equipment and in accordance with Sec. 3280.715(a)(3). If the
capacity information provided is based on entrances to the air supply
duct at other than the furnace plenum, the manufacturer shall indicate
the correct supply air entrance and return air exit locations.
(c) Comfort cooling information. For each manufactured home
designated, either ``suitable for'' or ``provided with'' a central air
conditioning system, the manufacturer shall provide comfort cooling
information specific to the manufactured home necessary to complete the
cooling load calculations. The comfort cooling information shall include
a statement to read as follows:

To determine the required capacity of equipment to cool a home
efficiently and economically, a cooling load (heat gain) calculation is
required. The cooling load is dependent on the orientation, location and
the structure of the home. Central air conditioners operate most
efficiently and provide the greatest comfort when their capacity closely
approximates the calculated cooling load. Each home's air conditioner
should be sized in accordance with chapter 22 of the American Society of
Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Handbook
of Fundamentals, 1989 Edition, once the location and orientation are
known.

Information Provided by the Manufacturer Necessary to Calculate Sensible
Heat Gain

Walls (without windows and doors)............................... U
Ceilings and roofs of light color............................... U
Ceilings and roofs of dark color................................ U
Floors.......................................................... U
Air ducts in floor.............................................. U
Air ducts in ceiling............................................ U
Air ducts installed outside the home............................ U

Information necessary to calculate duct areas.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55012, Oct. 25, 1993]

Subpart G--Plumbing Systems

Sec. 3280.601 Scope.

Subpart G of this standard covers the plumbing materials, fixtures,
and equipment installed within or on manufactured homes. It is the
intent of this subpart to assure water supply, drain, waste and vent
systems which permit satisfactory functioning and provide for health and
safety under all conditions of normal use.

Sec. 3280.602 Definitions.

The following definitions are applicable to subpart G only:
Accessible, when applied to a fixture, connection, appliance or
equipment, means having access thereto, but which may require removal of
an access panel or opening of a door.
Air gap (water distribution system) means the unobstructed vertical
distance through the free atmosphere between the lowest opening from any
pipe or faucet supplying water to a tank, plumbing fixture, water
supplied appliances, or other device and the flood level rim of the
receptacle.
Anti-siphon trap vent device means a device which automatically
opens to admit air to a fixture drain above the connection of the trap
arm so as to prevent siphonage, and closes tightly when the pressure
within the drainage

[[Page 149]]

system is equal to or greater than atmospheric pressure so as to prevent
the escape of gases from the drainage system into the manufactured home.
Backflow means the flow of water or other liquids, mixtures, or
substances into the distributing pipes of a potable supply of water from
any source or sources other than its intended sources.
Backflow connection means any arrangement whereby backflow can
occur.
Backflow preventer means a device or means to prevent backflow.
Branch means any part of the piping system other than a riser, main
or stack.
Common vent means a vent connecting at the junction of fixture
drains and serving as a vent for more than one fixture.
Continuous vent means a vertical vent that is a continuation of the
drain to which it connects.
Continuous waste means a drain from two or more fixtures connected
to a single trap.
Critical level means a point established by the testing laboratory
(usually stamped on the device by the manufacturer) which determines the
minimum elevation above the flood level rim of the fixture or receptacle
served on which the device may be installed. When a backflow prevention
device does not bear a critical level marking, the bottom of the vacuum
breaker, combination valve, or of any such approved or listed device
shall constitute the critical level.
Cross connection means any physical connection or arrangement
between two otherwise separate systems or sources, one of which contains
potable water and the other either water, steam, gas or chemical of
unknown or questionable safety whereby there may be a flow from one
system or source to the other, the direction of flow depending on the
pressure differential between the two systems.
Developed length means that length of pipe measured along the center
line of the pipe and fittings.
Diameter, unless otherwise specifically stated, means the nominal
(inside) diameter designated commercially.
Drain means a pipe that carries waste, water, or water-borne waste
in a drainage system.
Drain connector means the removable extension, consisting of all
pipes, fittings and appurtenances, from the drain outlet to the drain
inlet serving the manufactured home.
Drain outlet means the lowest end of the main or secondary drain to
which a sewer connection is made.
Drainage system means all piping within or attached to the structure
that conveys sewage or other liquid waste to the drain outlet, not
including the drain connector.
Fixture drain means the drain from the trap of a fixture to the
junction of that drain with any other drain pipe.
Fixture supply means the water supply pipe connecting a fixture to a
branch water supply pipe or directly to a main water supply pipe.
Flood-level means the level in the receptacle over which water would
overflow to the outside of the receptacle.
Flooded means the condition which results when the liquid in a
container or receptacle rises to the flood-level.
Flush tank means that portion of a water closet that is designed to
contain sufficient water to adequately flush the fixture.
Flush valve means a device located at the bottom of a flush tank for
flushing a water closet.
Flushometer tank: means a device integrated within an air
accumulator vessel which is designed to discharge a predetermined
quantity of water to fixtures for flushing purposes.
Flushometer valve means a device which discharges a predetermined
quantity of water to a fixture for flushing purposes and is closed by
direct water pressure.
Grade means the fall (slope) of a pipe in reference to a horizontal
plane expressed in inches per foot length.
Horizontal branch means any pipe extending laterally, which receives
the discharge from one or more fixture drains and connects to the main
drain.
Horizontal pipe means any pipe or fitting which makes an angle of
not more than 45 degrees with the horizontal.
Individual vent means a pipe installed to vent a fixture drain.

[[Page 150]]

Inlet coupling means the terminal end of the water system to which
the water service connection is attached. It may be a swivel fitting or
threaded pipe end.
Main means the principal artery of the system to which branches may
be connected.
Main drain means the lowest pipe of a drainage system which receives
sewage from all the fixtures within a manufactured home and conducts
these wastes to the drain outlet.
Main vent means the principal artery of the venting system to which
vent branches may be connected.
Offset means a combination of pipe and/or fittings that brings one
section of the pipe out of line but into a line parallel with the other
section.
Pitch. See Grade.
Plumbing appliance: means any one of a special class of plumbing
fixture which is intended to perform a special plumbing function. Its
operation and/or control may be dependent upon one or more energized
components, such as motors, control, heating elements, or pressure or
temperature-sensing elements. Such fixture may operate automatically
through one or more of the following actions: A time cycle, a
temperature range, a pressure range, a measured volume or weight, or the
fixture may be manually adjusted or controlled by the user or operator.
Plumbing appurtenance: means a manufactured device, or a
prefabricated assembly, or an on-the-job assembly of component parts,
and which is an adjunct to the basic piping system and plumbing system
and plumbing fixtures. An appurtenance demands no additional water
supply, nor does it add any discharge load to a fixture or the drainage
system.
Plumbing fixtures means receptacles, devices, or appliances which
are supplied with water or which receive liquid or liquid-borne wastes
for discharge into the drainage system.
Plumbing system means the water supply and distribution pipes;
plumbing fixtures, faucets and traps; soil, waste and vent pipes; and
water-treating or water-using equipment.
Primary vent. See main vent.
Relief vent means an auxiliary vent which permits additional
circulation of air in or between drainage and vent systems.
Secondary vent means any vent other than the main vent or those
serving each toilet.
Sewage means any liquid waste containing animal or vegetable matter
in suspension or solution, and may include liquids containing chemicals
in solution.
Siphonage means the loss of water seal from fixture traps resulting
from partial vacuum in the drainage system which may be of either of the
following two types, or a combination of the two:
(a) Self-siphonage resulting from vacuum in a fixture drain
generated solely by the discharge of the fixture served by that drain,
or,
(b) Induced siphonage resulting from vacuum in the drainage system
generated by the discharge of one or more fixtures other than the one
under observation.
Trap means a fitting or device designed and constructed to provide a
liquid seal that will prevent the back passage of air without materially
affecting the flow of liquid waste through it.
Trap arm means the portion of a fixture drain between a trap and its
vent.
Trap seal means the verticle depth of liquid that a trap will
retain.
Vacuum breaker. See backflow preventer.
Vent cap means the device or fitting which protects the vent pipe
from foreign substance with an opening to the atmosphere equal to the
area of the vent it serves.
Vent system means that part of a piping installation which provides
circulation of air within a drainage system.
Vertical pipe means any pipe or fitting which makes an angle of not
more than 45 degrees with the vertical.
Water closet drain means that part of the drainage piping which
receives the discharge from each individual water closet.
Water connection means the fitting or point of connection for the
manufactured home water distribution system designed for connection to a
water supply.
Water connector means the removable extension connecting the
manufactured home water distribution system to the water supply.

[[Page 151]]

Water distribution system means potable water piping within or
permanently attached to the manufactured home.
Wet vent means a vent which also serves as a drain for one or more
fixtures.
Wet vented drainage system means the specially designed system of
drain piping that also vents one or more plumbing fixtures by means of a
common waste and vent pipe.
Whirlpool bathtub means a plumbing appliance consisting of a bathtub
fixture which is equipped and fitted with a circulation piping system,
pump, and other appurtenances and is so designed to accept, circulate,
and discharge bathtub water upon each use.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4584, Feb. 12, 1987; 52 FR 47553, Dec. 15, 1987; 58
FR 55012, Oct. 25, 1993]

Sec. 3280.603 General requirements.

(a) Minimum requirements. Any plumbing system installed in a
manufactured home shall conform, at least, with the provisions of this
subpart.
(1) General. The plumbing system shall be of durable material, free
from defective workmanship, and so designed and constructed as to give
satisfactory service for a reasonable life expectancy.
(2) Conservation. Water closets shall be selected and adjusted to
use the minimum quantity of water consistent with proper performance and
cleaning.
(3) Connection to drainage system. All plumbing, fixtures, drains,
appurtenances, and appliances designed or used to receive or discharge
liquid waste or sewage shall be connected to the manufactured home
drainage system in a manner provided by this standard.
(4) Workmanship. All design, construction, and workmanship shall be
in conformance with accepted engineering practices and shall be of such
character as to secure the results sought to be obtained by this
standard.
(5) Components. Plumbing materials, devices, fixtures, fittings,
equipment, appliances, appurtenance, and accessories intended for use in
or attached to a manufactured home shall conform to one of the
applicable standards referenced in Sec. 3280.604. Where an applicable
standard is not referenced, or an alternative recognized standard is
utilized, the plumbing component shall be listed by a nationally
recognized testing laboratory, inspection agency or other qualified
organization as suitable for the intended use.
(6) Prohibited fittings and practices. (i) Drainage or vent piping
shall not be drilled and tapped for the purpose of making connections.
(ii) Except as specifically provided elsewhere in this standard,
vent pipes shall not be used as waste or drain pipes.
(iii) Fittings, connections, devices, or methods of installation
that obstruct or retard the flow of sewage, or air in the drainage or
venting systems in an amount greater than the normal frictional
resistance to flow shall not be used unless their use is acceptable in
this standard or their use is accepted as having a desirable and
acceptable function of ultimate benefit to the proper and continued
functioning of the plumbing system.
(iv) Cracks, holes, or other imperfections in materials shall not be
concealed by welding, brazing, or soldering or by paint, wax, tar, or
other leak-sealing or repairing agents.
(v) Piping, fixtures or equipment shall be located so as not to
interfere with the normal use or with the normal operation and use of
windows, doors or other required facilities.
(vi) Galvanized pipe shall not be bent or welded.
(7) Alignment of fittings. All valves, pipes, and fittings shall be
installed in correct relationship to the direction of flow.
(b) Protective requirements. (1) Cutting structural members.
Structural members shall not be unnecessarily or carelessly weakened by
cutting or notching.
(2) Exposed piping. All piping, pipe threads, hangers, and support
exposed to the weather, water, mud, and road hazard, and subject to
damage therefrom, shall be painted, coated, wrapped, or otherwise
protected from deterioration.
(3) Road damage. Pipes, supports, drains, outlets, or drain hoses
shall not extend or protrude in a manner where

[[Page 152]]

they could be unduly subjected to damage during transit.
(4) Freezing. All piping and fixtures subject to freezing
temperatures shall be insulated or protected to prevent freezing, under
normal occupancy. The manufacturer shall provide:
(i) Written installation instructions for the method(s) required for
compliance to this section;
(ii) A statement in his installation instructions that if heat tape
is used it shall be listed for use with manufactured homes;
(iii) A receptacle outlet for the use of a heat tape located on the
underside of the manufactured home within 2 feet of the water supply
inlet. The receptacle outlet provided shall not be placed on a branch
circuit which is protected by a ground fault circuit interrupter.
(5) All piping, except the fixture trap, shall be designed to allow
drainage.
(6) Rodent resistance. All exterior openings around piping and
equipment shall be sealed to resist the entrance of rodents.
(7) Piping and electrical wiring shall not pass through the same
holes in walls, floors or roofs. Plastic piping shall not be exposed to
heat in excess of manufacturers recommendation or radiation from heat
producing appliances.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 54383, Oct. 5, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 58 FR 55012,
Oct. 25, 1993]

Sec. 3280.604 Materials.

(a) Minimum standards. Materials, devices, fixtures, fittings,
equipment, appliances, appurtenances and accessories shall conform to
one of the standards in the following table and be free from defects.
Where an appropriate standard is not indicated in the table or a
standard not indicated in the table is preferred, the item may be used
if it is listed. A listing is also required when so specified in other
sections of this subpart.
(b) Where more than one standard is referenced for a particular
material or component, compliance with only one of those standards is
acceptable. Exceptions:
(1) When one of the reference standards requires evaluation of
chemical, toxicity or odor properties which are not included in the
other standard, then conformance to the applicable requirements of each
standard shall be demonstrated;
(2) When a plastic material or component is not covered by the
Standards in the following table, it shall be certified as non-toxic in
accordance with NSF14-1990, ``Plastic Piping Components and Related
Materials.''

Ferrous Pipe and Fittings

Gray Iron Threaded Fittings--ANSI/ASME B16.4-1992.
Malleable Iron Threaded Fittings--ANSI/ASME B16.3-1992.
Material and Property Standard for Special Cast Iron Fittings--IAPMO PS
5-84.
Welding and Seamless Wrought Steel Pipe--ANSI/ASME B36.10-1979.
Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-
Coated, Welded and Seamless--ASTM A53-93.
Pipe Threads, General Purpose (Inch)--ANSI/ASME B1.20.1-1983.
Standard Specification for Cast Iron Soil Pipe and Fittings--ASTM A74-
92.
Standard Specification for Hubless Cast Iron Soil Pipe and Fittings for
Sanitary and Storm Drain, Waste, and Vent Piping Applications--CISPI-
301-90.

Nonferrous Pipe and Fittings

Standard Specification for Seamless Copper Pipe, Standard Sizes--ASTM
B42-93.
Standard Specification for General Requirements for Wrought Seamless
Copper and Copper-Alloy Tube--ASTM B251-93.
Standard Specification for Seamless Copper Water Tube--ASTM B 88-93.
Standard Specification for Copper Drainage Tube (DWV)--ASTM B306-92.
Wrought Copper and Copper Alloy Solder-Joint Pressure Fitting--ASME/ANSI
B16.22-1989.
Wrought Copper and Wrought Copper Alloy Solder-Joint Drainage Fittings-
DWV--ASME/ANSI B16.29-1986.
Cast Copper Alloy Solder-Joint Pressure Fittings--ANSI B16.18-1984.
Cast Copper Alloy Solder-Joint Drainage Fittings-DWV--ASME B16.23-1992.
Cast Copper Alloy Fittings for Flared Copper Tubes--ASME/ANSI B16.26-
1988.
Standard Specification for Seamless Red Brass Pipe, Standard Sizes--ASTM
B43-91.
Cast Bronze Threaded Fittings, Classes 125 and 250--ANSI/ASME B16.15-
1985.

Plastic Pipe and Fittings

Standard Specification Acrylonitrile-Butadiene-Styrene (ABS) Schedule 40
Plastic

[[Page 153]]

Drain, Waste, and Vent Pipe and Fittings--ASTM D2661-91.
Standard Specification for Poly (Vinyl Chloride) (PVC) Plastic Drain,
Waste, and Vent Pipe and Fittings--ASTM D2665-91b.
Standard Specification for Drain, Waste, and Vent (DWV) Plastic Fittings
Patterns--ASTM D3311-92.
Standard Specification for Acrylonitrile-Butadiene-Styrene (ABS)
Schedule 40, Plastic Drain, Waste, and Vent Pipe With a Cellular Core--
ASTM F628-91.
Standard Specification for Chlorinated Poly (Vinyl Chloride) (CPVC)
Plastic Hot- and Cold-Water Distribution Systems--ASTM D2846-92.
Standard Specification for Polybutylene (PB) Plastic Hot- and Cold-Water
Distribution Systems--ASTM D3309-92a.
Plastic Piping Components and Related Materials--ANSI/NSF 14-1990.

Miscellaneous

Standard Specification for Rubber Gaskets for Cast Iron Soil Pipe and
Fittings--ASTM C564-88.
Backflow Valves--ANSI A112.14.1-1975.
Plumbing Fixture Setting Compound--TTP 1536A-1975.
Material and Property Standard for Cast Brass and Tubing P-Traps--IAPMO
PS 2-89.
Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply
Systems--*ANSI Z21.22-1986, With Addendum Z21.22a-1990.
Standard Specification for Solvent Cement for Acrylonitrile-Butadiene-
Styrene (ABS) Plastic Pipe and Fittings--ASTM D2235-88.
Standard Specification for Solvent Cements for Poly (Vinyl Chloride)
(PVC) Plastic Piping Systems--ASTM D2564-91a.
Specification for Neoprene Rubber Gaskets for HUB and Spigot Cast Iron
Soil Pipe and Fittings--CISPI-HSN-85.
Plumbing System Components for Manufactured Homes and Recreational
Vehicles--ANSI/NSF 24-1988.
Material and Property Standard for Diversion Tees and Twin Waste Elbow--
IAPMO PS 9-84.
Material and Property Standard for Flexible Metallic Water Connectors--
IAPMO PS 14-89.
Material and Property Standard for Dishwasher Drain Airgaps--IAPMO PS
23-89.
Material and Property Standards for Backflow Prevention Assemblies--
IAPMO PS 31-91.

Plumbing Fixtures

Plumbing Fixtures (General Specifications)--FS WW-P-541E/GEN-1980.
Vitreous China Plumbing Fixtures--ANSI/ASME A112.19.2(M)-1990.
Enameled Cast Iron Plumbing Fixtures--ANSI/ASME A112.19.1M-1987.
Porcelain Enameled Formed Steel Plumbing Fixtures--ANSI/ASME
A112.19.4(M)-1984.
Plastic Bathtub Units With Addenda Z124.1a-1990 and Z124.16-1991--ANSI
Z124.1-1987.
Standard for Porcelain Enameled Formed Steel Plumbing Fixtures--IAPMO
TSC 22-85.
Plastic Shower Receptors and Shower Stalls With Addendum Z124.2a-1990--
ANSI Z124.2-1987.
Stainless Steel Plumbing Fixtures (Designed for Residential Use)--ANSI/
ASME A112.19.3M-1987.
Material and Property Standard for Drains for Prefabricated and Precast
Showers--IAPMO PS 4-90.
Plastic Lavatories with addendum Z124.3a-1990--ANSI Z124.3-1986.
Safety Performance Specifications and Methods of Test for Safety Glazing
Materials Used in Building--ANSI Z97.1-1984.
Plumbing Fixture Fittings--ANSI/ASME A112.18.1M-1989.
Trim for Water Closet, Bowls, Tanks, and Urinals--ANSI A112.19.5-1979.
Plastic Water Closets, Bowls and Tanks with Addenda Z124.4a-1990--ANSI
Z124.4-1986.
Whirlpool Bathtub Appliances--ASME/ANSI A112.19.7M-1987.
Performance Requirements for Individual Thermostatic Pressure Balancing
and Combination Control for Bathing Facilities--ASSE 1016-1988, (ANSI
1990).
Performance Requirements for Pressurized Flushing Devices (Flushometers)
For Plumbing Fixtures--ASSE 1037-1990 (ANSI-1990).
Performance Requirements for Water Closet Flush Tank Fill Valves
(Ballcocks)--ASSE 1002 Revision 5-1986, (ANSI/ASSE-1979).
Performance Requirements for Hand-held Showers--ASSE 1014-1989 (ANSI-
1990).
Hydrants for Utility and Maintenance Use--ANSI/ASME A112.21.3M-1985.
Performance Requirements for Home Laundry Equipment--ASSE 1007-1986.
Performance Requirements for Hot Water Dispensers, Household Storage
Type Electrical--ASSE 1023-ANSI/ASSE-1979.
Plumbing Requirements for Residential Use (Household) Dishwashers--ASSE
1006, ASSE/ANSI-1986.
Performance Requirements for Household Food Waste Disposer Units--ASSE
1008-1986.
Performance Requirements for Temperature Activated Mixing Valves for
Primary Domestic Use--ASSE 1017-1986.
Water Hammer Arresters--ANSI A112.26.1-1969 (R 1975).
Suction Fittings for Use in Swimming Pools, Wading Pools, Spas, Hot Tubs
and Whirlpool Bathtub Appliances--ASME/ANSI A112.19.8M-1989.

[[Page 154]]

Air Gaps in Plumbing Systems--ASME A112.1.2-1991.
Performance Requirements for Diverters for Plumbing Faucets with Hose
Spray, Anti-Siphon Type, Residential Applications--ASSE 1025-ANSI/ASSE-
1978.
Performance Requirements for Pipe Applied Atmospheric Type Vacuum
Breakers--ASSE 1001 ASSE/ASNI-1990.
Performance Requirements for Hose Connection Vacuum Breakers--ASSE 1011-
1981 (ANSI-1982).
Performance Requirements for Wall Hydrants, Frost Proof Automatic
Draining, Anti-Backflow Types--ANSI/ASSE 1019-1978.

[58 FR 55013, Oct. 25, 1993]

Sec. 3280.605 Joints and connections.

(a) Tightness. Joints and connections in the plumbing system shall
be gastight and watertight for the pressures required under testing
procedures.
(1) Assembling of pipe. All joints and connections shall be
correctly assembled for tightness. Pipe threads shall be fully engaged
with the threads of the fitting. Plastic pipe and copper tubing shall be
inserted to the full depth of the solder cup or welding sockets of each
fitting. Pipe threads and slip joints shall not be wrapped with string,
paper, putty, or similar fillers.
(2) Threaded joints. Threads for screw pipe and fittings shall
conform to the approved or listed standard. Pipe ends shall be reamed
out to size of bore. All burrs, chips, cutting oil and foreign matter
shall be removed. Pipe joint cement or thread lubricant shall be of
approved type and applied to male threads only.
(3) Solder joints. Solder joints for tubing shall be made with
approved or listed solder type fittings. Surfaces to be soldered shall
be cleaned bright. The joints shall be properly fluxed with noncorrosive
paste type flux and, for manufactured homes to be connected to a public
water system, made with solder having not more than 0.2 percent lead.
(4) Plastic pipe, fittings and joints. Plastic pipe and fittings
shall be joined by installation methods recommended by the manufacturer
or in accordance with the provisions of a recognized, approved, or
listed standard.
(5) Union joints. Metal unions in water piping shall have metal-to-
metal ground seats.
(6) Flared joints. Flared joints for soft-copper water tubing shall
be made with approved or listed fittings. The tubing shall be expanded
with a proper flaring tool.
(7) Cast iron soil pipe joints. Approved or listed cast iron pipe
may be joined as follows:
(i) Approved or listed hubless pipe as per the manufacturer's
recommendation.
(ii) Hub and plain-end soil pipe may be joined by compression
fittings per the manufacturer's recommendation.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 53 FR 23611, June 23, 1988]

Sec. 3280.606 Traps and cleanouts.

(a) Traps--(1) Traps required. Each plumbing fixture, except listed
toilets, shall be separately trapped by approved water seal ``P'' traps.
All traps shall be effectively vented.
(2) Dual fixtures. A two-compartment sink, two single sinks, two
lavatories, or a single sink and a single lavatory with waste outlets
not more than 30 inches apart and in the same room and flood level rims
at the same level may be connected to one ``P'' trap and may be
considered as a single fixture for the purpose of drainage and vent
requirements.
(3) Prohibited traps. A trap which depends for its seal upon
concealed interior partitions shall not be used. Full ``S'' traps, bell
traps, drum traps, crown-vented traps, and running traps are prohibited.
Fixtures shall not be double-trapped.
(4) Material and design. Each trap shall be self-cleaning with a
smooth and uniform interior waterway. Traps shall be manufactured of
cast iron, cast brass, or drawn brass tubing of not less than No. 20
Brown and Sharpe gage, or approved or listed plastic, or other approved
or listed material. Union joints for a trap shall be beaded to provide a
shoulder for the union nut. Each trap shall have the manufacturer's name
stamped or cast in the body of the trap, and each tubing trap shall show
the gage of the tubing.
(5) Trap seal. Each ``P'' trap shall have a water seal of not less
than 2 inches and not more than 4 inches and shall be set true to its
seal.

[[Page 155]]

(6) Size. Traps shall be not less than 1\1/4\ inches in diameter. A
trap shall not be larger than the waste pipe to which it is connected.
(7) Location. Each trap shall be located as close to its vent and to
its fixture outlet as structural conditions will permit.
(8) Length of tailpiece. The vertical distance from a trap to the
fixture outlet shall not exceed 24 inches.
(9) Installation. (i) Grade of trap arm. The piping between a ``P''
trap and the fixture tee or the vented waste line shall be graded \1/4\
inch per foot towards the vent and in no event shall have a slope
greater than its diameter. The vent opening at fixture tees shall not be
below the weir of the ``P'' trap outlet.
(ii) Trap arm offset. The piping between the ``P'' trap and vent may
change direction or be offset horizontally with the equivalent of no
more than 180 degrees total change in direction with a maximum of 90
degrees by any one fitting.
(iii) Concealed traps. Traps with mechanical joints shall be
accessible for repair and inspection.
(iv) Removability of traps, etc. Traps shall be designed and
installed so the ``U'' bend is removable without removing the strainers
from the fixture. Continuous waste and tail pieces which are permanently
attached to the ``U'' bend shall also be removable without removing the
strainer from the fixture.
(b) Cleanout openings--(1) Location of cleanout fittings. (i)
Cleanouts shall be installed if the drainage system cannot be cleaned
through fixtures, drains, or vents. Cleanouts shall also be provided
when fittings of more than 45 degrees are used to affect an offset
except where long turn ells are used which provide sufficient ``sweep''
for cleaning.
(ii) A full size cleanout shall be installed at the upper end of any
section of drain piping which does not have the required minimum slope
of \1/4\ inch per foot grade.
(iii) A cleaning tool shall not be required to pass through more
than 360 degrees of fittings, excluding removable ``P'' traps, to reach
any part of the drainage system. Water closets may be removed for
drainage system access.
(2) Access to cleanouts. Cleanouts shall be accessible through an
unobstructed minimum clearance of 12 inches directly in front of the
opening. Each cleanout fitting shall open in a direction opposite to the
flow or at right angles to the pipe. Concealed cleanouts that are not
provided with access covers shall be extended to a point above the floor
or outside of the manufactured home, with pipe and fittings installed,
as required, for drainage piping without sags and pockets.
(3) Material. Plugs and caps shall be brass or approved or listed
plastic, with screw pipe threads.
(4) Design. Cleanout plugs shall have raised heads except that plugs
at floor level shall have counter-sunk slots.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55014, Oct. 25, 1993]

Sec. 3280.607 Plumbing fixtures.

(a) General requirements--(1) Quality of fixtures. Plumbing fixtures
shall have smooth impervious surfaces, be free from defects and
concealed fouling surfaces, be capable of resisting road shock and
vibration, and shall conform in quality and design to listed standards.
Fixtures shall be permanently marked with the manufacturer's name or
trademark.
(2) Strainers. The waste outlet of all plumbing fixtures, other than
toilets, shall be equipped with a drain fitting that will provide an
adequate unobstructed waterway.
(3) Fixture connections. Fixture tailpieces and continuous wastes in
exposed or accessible locations shall be not less than No. 20 Brown and
Sharpe gage seamless drawn-brass tubing or other approved pipe or tubing
materials. Inaccessible fixture connections shall be constructed
according to the requirements for drainage piping. Each fixture
tailpiece, continuous waste, or waste and overflow shall be not less
than 1\1/2\ inches for sinks of two or more compartments, dishwashers,
clothes washing machines, laundry tubs, bath tubs, and not less than
1\1/4\ inches for lavatories and single compartment sinks having a 2
inch maximum drain opening.
(4) Concealed connections. Concealed slip joint connections shall be
provided

[[Page 156]]

with adequately sized unobstructed access panels and shall be accessible
for inspection and repair.
(5) Directional fitting. An approved or listed ``Y'' or other
directional-type branch fitting shall be installed in every tailpiece or
continuous waste that receives the discharge from food waste disposal
units, dishwashing, or other force-discharge fixture or appliance. (See
also Sec. 3280.607(b)(4)(ii).)
(b) Fixtures. (1) Spacing. All plumbing fixtures shall be so
installed with regard to spacing as to be reasonably accessible for
their intended use.
(2) Water closets. (i) Water closets shall be designed and
manufactured according to approved or listed standards and shall be
equipped with a water flushing device capable of adequately flushing and
cleaning the bowl at each operation of the flushing mechanism.
(ii) Water closet flushing devices shall be designed to replace the
water seal in the bowl after each operation. Flush valves, flushometer
valves, flushometer tanks and ballcocks shall operate automatically to
shut off at the end of each flush or when the tank is filled to
operating capacity.
(iii) Flush tanks shall be fitted with an overflow pipe large enough
to prevent flooding at the maximum flow rate of the ball cock. Overflow
pipes shall discharge into the toilet, through the tank.
(iv) Water closets that have fouling surfaces that are not
thoroughly washed at each discharge shall be prohibited. Any water
closet that might permit the contents of the bowl to be siphoned back
into the water system shall be prohibited.
(v) Floor connection. Water closets shall be securely bolted to an
approved flange or other approved fitting which is secured to the floor
by means of corrosion-resistant screws. The bolts shall be of solid
brass or other corrosion-resistant material and shall be not less than
one-fourth inch in diameter. A watertight seal shall be made between the
water closet and flange or other approved fitting by use of a gasket or
sealing compound.
(3) Shower compartment. (i) Each compartment stall shall be provided
with an approved watertight receptor with sides and back extending at
least 1 inch above the finished dam or threshold. In no case shall the
depth of a shower receptor be less than 2 inches or more than 9 inches
measured from the top of the finished dam or threshold to the top of the
drain. The wall area shall be constructed of smooth, noncorrosive, and
nonabsorbent waterproof materials to a height not less than 6 feet above
the bathroom floor level. Such walls shall form a watertight joint with
each other and with the bathtub, receptor or shower floor. The floor of
the compartment shall slope uniformly to the drain at not less than one-
fourth nor more than one-half inch per foot.
(ii) The joint around the drain connection shall be made watertight
by a flange, clamping ring, or other approved listed means.
(iii) Shower doors and tub and shower enclosures shall be
constructed so as to be waterproof and, if glazed, glazing shall comply
with the standard for Safety Performance Specifications and Methods of
Test for Safety Glazing Materials Used in Buildings, ANSI Z97.1-1984.
(iv) Prefabricated plumbing fixtures shall be approved or listed.
(4) Dishwashing machines. (i) A dishwashing machine shall not be
directly connected to any waste piping, but shall discharge its waste
through a fixed air gap installed above the machine, or through a high
loop as specified by the dishwashing machine manufacturer, or into an
open standpipe-receptor with a height greater than the washing
compartment of the machine. When a standpipe is used, it shall be at
least 18 inches but not more than 30 inches above the trap weir. The
drain connections from the air gap or high loop may connect to an
individual trap, to a directional fitting installed in the sink
tailpiece or to an opening provided on the inlet side of a food waste
disposal unit.
(ii) Drain from a dishwashing machine shall not be connected to a
sink tailpiece, continuous waste line, or trap on the discharge side of
a food waste disposal unit.
(5) Clothes washing machines. (i) Clothes washing machines shall
drain either into a properly vented trap, into a laundry tub tailpiece
with watertight

[[Page 157]]

connections, into an open standpipe receptor, or over the rim of a
laundry tub.
(ii) Standpipes shall be 1\1/2\ inches minimum nominal iron pipe
size, 1\1/2\ inches diameter nominal brass tubing not less than No. 20
Brown and Sharpe gage, or 1\1/2\ inches approved plastic materials.
Receptors shall discharge into a vented trap or shall be connected to a
laundry tub tailpiece by means of an approved or listed directional
fitting. Each standpipe shall extend not less than 18 inches or more
than 30 inches above its trap and shall terminate in an accessible
location no lower than the top of clothes washing machine. A removable
tightfitting cap or plug shall be installed on the standpipe when
clothes washer is not provided.
(iii) Clothes washing machine drain shall not be connected to the
tailpiece, continuous waste, or trap of any sink or dishwashing machine.
(c) Installation--(1) Access. Each plumbing fixture and standpipe
receptor shall be located and installed in a manner to be accessible for
usage, cleaning, repair and replacement. Access to diverter valves and
other connections from the fixture hardware is not required.
(2) Alignment. Fixtures shall be set level and in true alignment
with adjacent walls. Where practical, piping from fixtures shall extend
to nearest wall.
(3) Brackets. Wall-hung fixtures shall be rigidly attached to walls
by metal brackets or supports without any strain being transmitted to
the piping connections. Flush tanks shall be securely fastened to
toilets or to the wall with corrosive-resistant materials.
(4) Tub supports. Bathtub rims at wall shall be supported on metal
hangers or on end-grain wood blocking attached to the wall unless
otherwise recommended by the manufacturer of the tub.
(5) Fixture fittings. Faucets and diverters shall be installed so
that the flow of hot water from the fittings corresponds to the left-
hand side of the fitting.
(6) Whirlpool bathtub appliances--(i) Access panel. A door or panel
of sufficient size shall be installed to provide access to the pump for
repair and/or replacement.
(ii) Piping drainage. The circulation pump shall be accessibly
located above the crown weir of the trap. The pump drain line shall be
properly sloped to drain the volute after fixture use.
(iii) Piping. Whirlpool bathtub circulation piping shall be
installed to be self-draining.
(iv) Electrical. Refer to the National Electrical Code, NFPA 70-
1993, Article 685G.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 961, Jan. 4, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 52 FR 4586,
Feb. 12, 1987; 58 FR 55014, Oct. 25, 1993]

Sec. 3280.608 Hangers and supports.

(a) Strains and stresses. Piping in a plumbing system shall be
installed without undue strains and stresses, and provision shall be
made for expansion, contraction, and structural settlement.
(b) Piping supports. Piping shall be secured at sufficiently close
intervals to keep the pipe in alignment and carry the weight of the pipe
and contents. Unless otherwise stated in the standards for specific
materials shown in the table in Sec. 3280.604(a), or unless specified by
the pipe manufacturer, plastic drainage piping shall be supported at
intervals not to exceed 4 feet and plastic water piping shall be
supported at intervals not to exceed 3 feet.
(c) Hangers and anchors. (1) Hangers and anchors shall be of
sufficient strength to support their proportional share of the pipe
alignments and prevent rattling.
(2) Piping shall be securely attached to the structure by hangers,
clamps, or brackets which provide protection against motion, vibration,
road shock, or torque in the chassis.
(3) Hangers and straps supporting plastic pipe shall not compress,
distort, cut or abrade the piping and shall allow free movement of the
pipe.

Sec. 3280.609 Water distribution systems.

(a) Water supply--(1) Supply piping. Piping systems shall be sized
to provide an adequate quantity of water to each plumbing fixture at a
flow rate sufficient to keep the fixture in a clean and sanitary
condition without any danger of backflow or siphonage. (See

[[Page 158]]

table in Sec. 3280.609(f)(1)). The manufacturer shall include in his
written installation instructions that the manufactured home has been
designed for an inlet water pressure of 80 psi, and a statement that
when the manufactured home is to be installed in areas where the water
pressure exceeds 80 psi, a pressure reducing valve should be installed.
(2) Hot water supply. Each manufactured home equipped with a kitchen
sink, and bathtub and/or shower shall be provided with a hot water
supply system including a listed water heater.
(b) Water outlets and supply connections--(1) Water connection. Each
manufactured home with a water distribution system shall be equipped
with a \3/4\ inch threaded inlet connection. This connection shall be
tagged or marked ``Fresh Water Connection'' (or marked ``Fresh Water
Fill''). A matching cap or plug shall be provided to seal the water
inlet when it is not in use, and shall be permanently attached to the
manufactured home or water supply piping. When a master cold water
shutoff full flow valve is not installed on the main feeder line in an
accessible location, the manufacturer's installation instructions shall
indicate that such a valve is to be installed in the water supply line
adjacent to the home. When a manufactured home includes expandable rooms
or is composed of two or more units, fittings or connectors designed for
such purpose shall be provided to connect any water piping. When not
connected, the water piping shall be protected by means of matching
threaded caps or plugs.
(2) Prohibited connections. (i) The installation of potable water
supply piping or fixture or appliance connections shall be made in a
manner to preclude the possibility of backflow.
(ii) No part of the water system shall be connected to any drainage
or vent piping.
(3) Rim outlets. The outlets of faucets, spouts, and similar devices
shall be spaced at least 1 inch above the flood level of the fixture.
(4) Appliance connections. Water supplies connected to clothes
washing or dishwashing machines shall be protected by an approved or
listed fixed air gap provided within the appliance by the manufacturer.
(5) Flushometer valves or manually operated flush valves. An
approved or listed vacuum breaker shall be installed and maintained in
the water supply line on the discharge side of a water closet
flushometer valve or manually operated flush valve. Vacuum breakers
shall have a minimum clearance of 6 inches above the flood level of the
fixture to the critical level mark unless otherwise permitted in their
approval.
(6) Flush tanks. Water closet flush tanks shall be equipped with an
approved or listed anti-siphon ball cock which shall be installed and
maintained with its outlet or critical level mark not less than 1 inch
above the full opening of the overflow pipe.
(7) Hose bibbs. When provided, all exterior hose bibbs and laundry
sink hose connections shall be protected by a listed non-removable
backflow prevention device. This is not applicable to hose connections
provided for automatic washing machines with built-in backflow
prevention.
(8) Flushometer tanks. Flushometer tanks shall be equipped with an
approved air gap on the vacuum breaker assembly located above the flood
level rim above the fixture.
(c) Water heater safety devices--(1) Relief valves. (i) All water
heaters shall be installed with approved and listed fully automatic
valve or valves designed to provide temperature and pressure relief.
(ii) Any temperature relief valve or combined pressure and
temperature relief valve installed for this purpose shall have the
temperature sensing element immersed in the hottest water within the
upper 6 inches of the tank. It shall be set to start relieving at a
pressure of 150 psi or the rated working pressure of the tank whichever
is lower and at or below a water temperature of 210 deg. F.
(iii) Relief valves shall be provided with full-sized drains, with
cross sectional areas equivalent to that of the relief valve outlet,
which shall be directed downward and discharge beneath the manufactured
home. Drain lines shall be of a material listed for hot water
distribution and shall drain fully by gravity, shall not be trapped,

[[Page 159]]

and shall not have their outlets threaded, and the end of the drain
shall be visible for inspection.
(d) Materials--(1) Piping material. Water pipe shall be of standard
weight brass, galvanized wrought iron, galvanized steel, Type K, L or M
copper tubing, approved or listed plastic or other approved or listed
material.
(i) Plastic piping. All plastic water piping and fittings in
manufactured homes must be listed for use with hot water.
(ii) [Reserved]
(2) Fittings. Appropriate fittings shall be used for all changes in
size and where pipes are joined. The material and design of fittings
shall conform to the type of piping used. Special consideration shall be
given to prevent corrosion when dissimilar metals are joined.
(i) Fittings for screw piping shall be standard weight galvanized
iron for galvanized iron and steel pipe, and of brass for brass piping.
They shall be installed where required for change in direction,
reduction of size, or where pipes are joined together.
(ii) Fittings for copper tubing shall be cast brass or drawn copper
(sweat-soldered) or shall be approved or listed fittings for the purpose
intended.
(3) Prohibited material. Used piping materials shall not be
permitted. Those pipe dopes, solder, fluxes, oils, solvents, chemicals,
or other substances that are toxic, corrosive, or otherwise detrimental
to the water system shall not be used. In addition, for those
manufactured homes to be connected to a public water system, all water
piping shall be lead-free (as defined in section 109(c)(2) of the Safe
Drinking Water Act Amendments of 1986) with solders and flux containing
not more than 0.2 percent lead and pipes and pipe fittings containing
not more than 8.0 percent lead.
(e) Installation of piping--(1) Minimum requirement. All piping
equipment, appurtenances, and devices shall be installed in workmanlike
manner and shall conform with the provisions and intent of this
standard.
(2) Screw pipe. Iron pipe-size brass or galvanized iron or steel
pipe fittings shall be joined with approved or listed standard pipe
threads fully engaged in the fittings. Pipe ends shall be reamed to the
full bore of the pipe. Pipe-joint compound shall be insoluble in water,
shall be nontoxic and shall be applied to male threads only.
(3) Solder fittings. Joints in copper water tubes shall be made by
the appropriate use of approved cast brass or wrought copper fittings,
properly soldered together. The surface to be soldered shall be
thoroughly cleaned bright mechanically. The joints shall be properly
fluxed and made with a solder that contains no more than 0.2 percent
lead.
(4) Flared fittings. A flaring tool shall be used to shape the ends
of flared tubing to match the flare of fittings.
(5) Plastic pipe and fittings. Plastic pipe and fittings shall be
joined by installation methods recommended by the manufacturer or in
accordance with provisions of a listed standard.
(f) Size of water supply piping--(1) Minimum size. The size of water
supply piping and branch lines shall not be less than sizes shown in the
following table:

Minimum Size Tubing and Pipe for Water Distribution Systems
------------------------------------------------------------------------
Tubing (nominal)
------------------------ Pipe iron
Number of fixtures Outer pipe size
Diameter diameter (inches)
(inches) (inches)
------------------------------------------------------------------------
1................................... *\1/4\ \3/8\ \1/2\
2................................... \3/8\ \1/2\ \1/2\
3................................... \1/2\ \5/8\ \1/2\
4................................... \1/2\ \5/8\ \1/2\
5 or more........................... \3/4\ \7/8\ \3/4\
------------------------------------------------------------------------
*6 ft maximum length.

Exceptions to table: \3/8\ inch nominal diameter or \1/2\ inch OD
minimum size for clothes washing or dishwashing machines, unless larger
size is recommended by the fixture manufacturer. \1/2\ inch nominal
diameter or \5/8\ inch OD minimum size for flushometer or metering type
valves unless otherwise specified in their listing. No galvanized screw
piping shall be less than \1/2\ inch iron pipe size.
(2) Sizing procedure. Both hot and cold water piping systems shall
be computed by the following method:
(i) Size of branch. Start at the most remote outlet on any branch of
the hot or cold water piping and progressively count towards the water
service connection, computing the total number of fixtures supplied
along each section of

[[Page 160]]

piping. Where branches are joined together, the number of fixtures on
each branch shall be totalled so that no fixture is counted twice.
Following down the left-hand column of the preceding table a
corresponding number of fixtures will be found. The required pipe or
tubing size is indicated in the other columns on the same line.
(ii) A water heater, food waste disposal unit, evaporative cooler or
ice maker shall not be counted as a water-using fixture when computing
pipe sizes.
(g) Line valves. Valves, when installed in the water supply
distribution system (except those immediately controlling one fixture
supply) and when fully opened, shall have a cross-sectional area of the
smallest orifice or opening, through which the water flows, at least
equal to the cross-sectional area of the nominal size of the pipe in
which the valve is installed.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4586, Feb. 12, 1987; 53 FR 23611, June 23, 1988; 58
FR 55014, Oct. 25, 1993]

Sec. 3280.610 Drainage systems.

(a) General. (1) Each fixture directly connected to the drainage
system shall be installed with a water seal trap (Sec. 3280.606(a)).
(2) The drainage system shall be designed to provide an adequate
circulation of air in all piping with no danger of siphonage,
aspiration, or forcing of trap seals under conditions of ordinary use.
(b) Materials--(1) Pipe. Drainage piping shall be standard weight
steel, wrought iron, brass, copper tube DWV, listed plastic, cast iron,
or other listed or approved materials.
(2) Fittings. Drainage fittings shall be recessed drainage pattern
with smooth interior waterways of the same diameter as the piping and
shall be of a material conforming to the type of piping used. Drainage
fittings shall be designed to provide for a \1/4\ inch per foot grade in
horizontal piping.
(i) Fittings for screw pipe shall be cast iron, malleable iron,
brass, or listed plastic with standard pipe threads.
(ii) Fittings for copper tubing shall be cast brass or wrought
copper.
(iii) Socket-type fittings for plastic piping shall comply with
listed standards.
(iv) Brass or bronze adaptor or wrought copper fittings shall be
used to join copper tubing to threaded pipe.
(c) Drain outlets. (1) Each manufactured home shall have only one
drain outlet.
(2) Clearance from drain outlet. The drain outlet shall be provided
with a minimum clearance of 3 inches in any direction from all parts of
the structure or appurtenances and with not less than 18 inches
unrestricted clearance directly in front of the drain outlet.
(3) Drain connector. The drain connector shall not be smaller than
the piping to which it is connected and shall be equipped with a water-
tight cap or plug matching the drain outlet. The cap or plug shall be
permanently attached to the manufactured home or drain outlet.
(4) The drain outlet and drain connector shall not be less than 3
inches inside diameter.
(5) Preassembly of drain lines. Section(s) of the drain system,
designed to be located underneath the home, are not required to be
factory installed when the manufacturer designs the system for site
assembly and also provides all materials and components, including
piping, fittings, cement, supports, and instructions necessary for
proper site installation.
(d) Fixture connections. Drainage piping shall be provided with
approved or listed inlet fittings for fixture connections, correctly
located according to the size and type of fixture to be connected.
(1) Water closet connection. The drain connection for each water
closet shall be 3 inches minimum inside diameter and shall be fitted
with an iron, brass, or listed plastic floor flange adaptor ring
securely screwed, soldered or otherwise permanently attached to the
drain piping, in an approved manner and securely fastened to the floor.
(2) [Reserved]
(e) Size of drainage piping--(1) Fixture load. Except as provided by
Sec. 3280.611(d), drain pipe sizes shall be determined by the type of
fixture and the total number connected to each drain.

[[Page 161]]

(i) A 1\1/2\ inch minimum diameter piping shall be required for one
and not more than three individually vented fixtures.
(ii) A 2-inch minimum diameter piping shall be required for four or
more fixtures individually vented.
(iii) A 3-inch minimum diameter piping shall be required for water
closets.
(f) Wet-vented drainage system. Plumbing fixture traps may connect
into a wet-vented drainage system which shall be designed and installed
to accommodate the passage of air and waste in the same pipe.
(1) Horizontal piping. All parts of a wet-vented drainage system,
including the connected fixture drains, shall be horizontal except for
wet-vented vertical risers which shall terminate with a 1\1/2\ inch
minimum diameter continuous vent. Where required by structural design,
wet-vented drain piping may be offset vertically when other vented
fixture drains or relief vents are connected to the drain piping at or
below the vertical offsets.
(2) Size. A wet-vented drain pipe shall be 2 inches minimum diameter
and at least one pipe size larger than the largest connected trap or
fixture drain. Not more than three fixtures may connect to a 2-inch
diameter wet-vented drain system.
(3) Length of trap arm. Fixture traps shall be located within the
distance given in Sec. 3280.611(c)(5). Not more than one trap shall
connect to a trap arm.
(g) Offsets and branch fittings--(1) Changes in direction. Changes
in direction of drainage piping shall be made by the appropriate use of
approved or listed fittings, and shall be of the following angles: 11\1/
4\, 22\1/2\, 45, 60, or 90 degrees; or other approved or listed fittings
or combinations of fittings with equivalent radius or sweep.
(2) Horizontal to vertical. Horizontal drainage lines, connecting
with a vertical pipe shall enter through 45-degree ``Y'' branches, 60-
degree ``Y'' branches, long-turn ``TY'' branches, sanitary ``T''
branches, or other approved or listed fittings or combination of
fittings having equivalent sweep. Fittings having more than one branch
at the same level shall not be used, unless the fitting is constructed
so that the discharge from any one branch cannot readily enter any other
branch. However, a double sanitary ``T'' may be used when the drain line
is increased not less than two pipe sizes.
(3) Horizontal to horizontal and vertical to horizontal. Horizontal
drainage lines connecting with other horizontal drainage lines or
vertical drainage lines connected with horizontal drainage lines shall
enter through 45-degree ``Y'' branches, long-turn ``TY'' branches, or
other approved or listed fittings or combination of fittings having
equivalent sweep.
(h) Grade of horizontal drainage piping. Except for fixture
connections on the inlet side of the trap, horizontal drainage piping
shall be run in practical alignment and have a uniform grade of not less
than \1/4\ inch per foot toward the manufactured home drain outlet.
Where it is impractical, due to the structural features or arrangement
of any manufactured home, to obtain a grade of \1/4\ inch per foot, the
pipe or piping may have a grade of not less than \1/8\ inch per foot,
when a full size cleanout is installed at the upper end.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4586, Feb. 12, 1987; 58 FR 55015, Oct. 25, 1993]

Sec. 3280.611 Vents and venting.

(a) General. Each plumbing fixture trap shall be protected against
siphonage and back pressure, and air circulation shall be ensured
throughout all parts of the drainage system by means of vents installed
in accordance with the requirements of this section and as otherwise
required by this standard.
(b) Materials--(1) Pipe. Vent piping shall be standard weight steel,
wrought iron, brass, copper tube DWV, listed plastic, cast iron or other
approved or listed materials.
(2) Fittings. Appropriate fittings shall be used for all changes in
direction or size and where pipes are joined. The material and design of
vent fittings shall conform to the type of piping used.
(i) Fittings for screw pipe shall be cast iron, malleable iron,
plastic, or brass, with standard pipe threads.
(ii) Fittings for copper tubing shall be cast brass or wrought
copper.

[[Page 162]]

(iii) Fittings for plastic piping shall be made to approved
applicable standards.
(iv) Brass adaptor fittings or wrought copper shall be used to join
copper tubing to threaded pipe.
(v) Listed rectangular tubing may be used for vent piping only
providing it has an open cross section at least equal to the circular
vent pipe required. Listed transition fittings shall be used.
(c) Size of vent piping--(1) Main vent. The drain piping for each
toilet shall be vented by a 1\1/2\ inch minimum diameter vent or
rectangular vent of venting cross section equivalent to or greater than
the venting cross section of a 1\1/2\ inch diameter vent, connected to
the toilet drain by one of the following methods:
(i) A 1\1/2\ inch diameter (min.) individual vent pipe or equivalent
directly connected to the toilet drain within the distance allowed in
Sec. 3280.611(c)(5), for 3-inch trap arms undiminished in size through
the roof,
(ii) A 1\1/2\ inch diameter (min.) continuous vent or equivalent,
indirectly connected to the toilet drain piping within the distance
allowed in Sec. 3280.611(c)(5) for 3 inch trap arms through a 2-inch wet
vented drain that carries the waste of not more than one fixture, or,
(iii) Two or more vented drains when at least one is wet-vented, or
2-inch diameter (minimum), and each drain is separately connected to the
toilet drain. At least one of the drains shall connect within the
distance allowed in Sec. 3280.611(c)(5) for 3-inch trap arms.
(2) Vent pipe areas. Each individually vented fixture with a 1\1/2\
inch or smaller trap shall be provided with a vent pipe equivalent in
area to a 1\1/4\ inch nominal pipe size. The main vent, toilet vent and
relief vent, and the continuous vent of wet-vented systems shall have an
area equivalent to 1\1/2\ inch nominal pipe size.
(3) Common vent. When two fixture traps located within the distance
allowed from their vent have their trap arms connected separately at the
same level into an approved double fitting, an individual vent pipe may
serve as a common vent without any increase in size.
(4) Intersecting vents. Where two or more vent pipes are joined
together, no increase in size shall be required; however, the largest
vent pipe shall extend full size through the roof.
(5) Distance of fixture trap from vent shall not exceed the values
given in the following table:

Maximum Distance of Fixtures From Vent Trap
------------------------------------------------------------------------
Size of fixture drain (inches) Distance trap to vent
------------------------------------------------------------------------
1\1/4\.................................... 4 ft. 6 in.
1\1/2\.................................... 4 ft 6 in.
2......................................... 5 ft.
3......................................... 6 ft.
------------------------------------------------------------------------

(d) Anti-siphon trap vent. An anti-siphon trap vent may be used as a
secondary vent system for plumbing fixtures protected by traps not
larger than 1\1/2\ inches, when installed in accordance with the
manufacturers' recommendations and the following conditions:
(1) Not more than two fixtures individually protected by the device
shall be drained by a common 1\1/2\ inch drain.
(2) Minimum drain size for three or more fixtures individually
protected by the device shall be 2 inches.
(3) A primary vent stack must be installed to vent the toilet drain
at the point of heaviest drainage fixture unit loading.
(4) The device shall be installed in a location that permits a free
flow of air and shall be accessible for inspection, maintenance, and
replacement and the sealing function shall be at least 6 inches above
the top of the trap arm.
(5) Materials for the anti-siphon trap vent shall be as follows:
(i) Cap and housing shall be listed acrylonitrile-butadiene-styrene,
DWV grade;
(ii) Stem shall be DWV grade nylon or acetal;
(iii) Spring shall be stainless steel wire, type 302;
(iv) Sealing disc shall be neoprene, conforming to CISPI-HSN-85, the
Specification for Neoprene Rubber Gaskets for HUB and Spigot Cast Iron
Soil Pipe and Fittings, and ASTM C 564-88, Standard Specification for
Rubber Gaskets for Case Iron Soil Pipe and Fittings, or, Silicone
Rubber, Low and High Temperature and Tear Resistant, Conforming to
Rubber, Silicone, FS ZZ-R-765B-1970, With 1971 Amendment

[[Page 163]]

1; and Liners, Case, and Sheet, Overwrap; Water-Vapor Proof or
Waterproof, Flexible, MIL-L-10547E-1975.
(e) Grade and connections--(1) Horizontal vents. Each vent shall
extend vertically from its fixture ``T'' or point of connection with the
waste piping to a point not less than 6 inches above the extreme flood
level of the fixture it is venting before offsetting horizontally or
being connected with any other vent pipe. Vents for horizontal drains
shall connect above the centerline of the drain piping ahead
(downstream) of the trap. Where required by structural conditions, vent
piping may offset below the rim of the fixture at the maximum angle or
height possible.
(f) Vent terminal--(1) Roof extension. Each vent pipe shall extend
through its flashing and terminate vertically, undiminished in size, not
less than 2 inches above the roof. Vent openings shall not be less than
3 feet away from any motor-driven air intake that opens into habitable
areas.
(2) Flashing. The opening around each vent pipe shall be made
watertight by an adequate flashing or flashing material.
(g) Vent caps. Vent caps, if provided, shall be of the removable
type (without removing the flashing from the roof). When vent caps are
used for roof space ventilation and the caps are identical to vent caps
used for the plumbing system, plumbing system caps shall be identified
with permanent markings.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 961, Jan. 4, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 58 FR 55015,
Oct. 25, 1993]

Sec. 3280.612 Tests and inspection.

(a) Water system. All water piping in the water distribution system
shall be subjected to a pressure test. The test shall be made by
subjecting the system to air or water at 100 psi for 15 minutes without
loss of pressure.
(b) Drainage and vent system and plumbing fixtures. The waste and
vent system shall be tested by one of the three following alternate
methods for evidence or indication of leakage:
(1) Water test. Before plumbing fixtures are connected, all of the
openings into the piping shall be plugged and the entire piping system
subjected to a static water test for 15 minutes by filling it with water
to the top of the highest vent opening. There shall be no evidence of
leakage.
(2) Air test. After all fixtures have been installed, the traps
filled with water, and the remaining openings securely plugged, the
entire system shall be subjected to a 2-inch (manometer) water column
air pressure test. If the system loses pressure, leaks may be located
with smoke pumped into the system, or with soap suds spread on the
exterior of the piping (Bubble test).
(3) Flood level test. The manufactured home shall be in a level
position, all fixtures shall be connected, and the entire system shall
be filled with water to the rim of the water closet bowl. (Tub and
shower drains shall be plugged). After all trapped air has been
released, the test shall be sustained for not less than 15 minutes
without evidence of leaks. Then the system shall be unplugged and
emptied. The waste piping above the level of the water closet bowl shall
then be tested and show no indication of leakage when the high fixtures
are filled with water and emptied simultaneously to obtain the maximum
possible flow in the drain piping.
(c) Fixture test. The plumbing fixtures and connections shall be
subjected to a flow test by filling them with water and checking for
leaks and retarded flow while they are being emptied.
(d) Shower compartments. Shower compartments and receptors shall be
tested for leaks prior to being covered by finish material. Each pan
shall be filled with water to the top of the dam for not less than 15
minutes without evidence of leakage.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 961, Jan. 4, 1977; 42
FR 54383, Oct. 5, 1977. Redesignated at 44 FR 20679, Apr. 6, 1979, as
amended at 58 FR 55015, Oct. 25, 1993]

Subpart H--Heating, Cooling and Fuel Burning Systems

Sec. 3280.701 Scope.

Subpart H of this standard covers the heating, cooling and fuel
burning equipment installed within, on, or external to a manufactured
home.

[[Page 164]]

Sec. 3280.702 Definitions.

The definitions in this subpart apply to subpart H only.
Accessible, when applied to a fixture, connection, appliance or
equipment, means having access thereto, but which may require the
removal of an access panel, door or similar obstruction.
Air conditioner blower coil system means a comfort cooling appliance
where the condenser section is placed external to the manufactured home
and evaporator section with circulating blower attached to the
manufactured home air supply duct system. Provision must be made for a
return air system to the evaporator/blower section. Refrigerant
connection between the two parts of the system is accomplished by
tubing.
Air conditioner split system means a comfort cooling appliance where
the condenser section is placed external to the manufactured home and
the evaporator section incorporated into the heating appliance or with a
separate blower/coil section within the manufactured home. Refrigerant
connection between the two parts of the system is accomplished by
tubing.
Air conditioning condenser section means that portion of a
refrigerated air cooling or (in the case of a heat pump) heating system
which includes the refrigerant pump (compressor) and the external heat
exchanger.
Air conditioning evaporator section means a heat exchanger used to
cool or (in the case of a heat pump) heat air for use in comfort cooling
(or heating) the living space.
Air conditioning self contained system means a comfort cooling
appliance combining the condenser section, evaporator and air
circulating blower into one unit with connecting ducts for the supply
and return air systems.
Air duct means conduits or passageways for conveying air to or from
heating, cooling, air conditioning or ventilation equipment, but not
including the plenum.
Automatic pump (oil lifter) means a pump, not an integral part of
the oil-burning appliance, that automatically pumps oil from the supply
tank and delivers the oil under a constant head to an oil-burning
appliance.
Btu. British thermal units means the quantity of heat required to
raise the temperature of one pound of water one degree Fahrenheit.
Btuh means British thermal units per hour.
Burner means a device for the final conveyance of fuel or a mixture
of fuel and air to the combustion zone.
Central air conditioning system means either an air conditioning
split system or an external combination heating/cooling system.
Class 0 air ducts means ducts of materials and connectors having a
fire-hazard classification of zero.
Class 1 air ducts means ducts of materials and connectors having a
flame-spread rating of not over 25 without evidence of continued
progressive combustion and a smoke-developed rating of not over 50.
Class 2 air ducts means ducts of materials and connectors having a
flame-spread rating of not over 50 without evidence of continued
progressive combustion and a smoke-developed rating of not over 50 for
the inside surface and not over 100 for the outside surface.
Clearance means the distance between the appliance, chimney, vent,
chimney or vent connector or plenum and the nearest surface.
Connector-Gas appliance: means a flexible or semi-rigid connector
used to convey fuel gas between a gas outlet and a gas appliance.
Energy Efficiency Ratio (EER) means the ratio of the cooling
capacity output of an air conditioner for each unit of power input.

EER=Capacity (Btuh)/Power input (watts)

External combination heating/cooling system means a comfort
conditioning system placed external to the manufactured home with
connecting ducts to the manufactured home for the supply and return air
systems.
Factory-built fireplace means a hearth, fire chamber and chimney
assembly composed of listed factory-built components assembled in
accordance with the terms of listing to form a complete fireplace.
Fireplace stove means a chimney connected solid fuel-burning stove
having part of its fire chamber open to the room.

[[Page 165]]

Fuel gas piping system means the arrangement of piping, tubing,
fittings, connectors, valves and devices designed and intended to supply
or control the flow of fuel gas to the appliance(s).
Fuel oil piping system means the arrangement of piping, tubing,
fittings, connectors, valves and devices designed and intended to supply
or control the flow of fuel oil to the appliance(s).
Gas clothes dryer means a device used to dry wet laundry by means of
heat derived from the combustion of fuel gases.
Gas refrigerator means a gas-burning appliance which is designed to
extract heat from a suitable chamber.
Gas supply connection means the terminal end or connection to which
a gas supply connector is attached.
Gas supply connector, manufactured home means a listed flexible
connector designed for connecting the manufactured home to the gas
supply source.
Gas vents means factory-built vent piping and vent fittings listed
by an approved testing agency, that are assembled and used in accordance
with the terms of their listings, for conveying flue gases to the
outside atmosphere.
(1) Type B gas vent means a gas vent for venting gas appliances with
draft hoods and other gas appliances listed for use with Type B gas
vents.
(2) Type BW gas vent means a gas vent for venting listed gas-fired
vented wall furnaces.
Heat producing appliance means all heating and cooking appliances
and fuel burning appliances.
Heating appliance means an appliance for comfort heating or for
domestic water heating.
Liquefied petroleum gases. The terms Liquefied petroleum gases, LPG
and LP-Gas as used in this standard shall mean and include any material
which is composed predominantly of any of the following hydrocarbons, or
mixtures of them: propane, propylene butanes (normal butane or
isobutane), and butylenes.
Plenum means an air compartment which is part of an air-distributing
system, to which one or more ducts or outlets are connected.
(1) Furnace supply plenum is a plenum attached directly to, or an
integral part of, the air supply outlet of the furnace.
(2) Furnace return plenum is a plenum attached directly to, or an
integral part of, the return inlet of the furnace.
Quick-disconnect device means a hand-operated device which provides
a means for connecting and disconnecting a gas supply or connecting gas
systems and which is equipped with an automatic means to shut off the
gas supply when the device is disconnected.
Readily accessible means direct access without the necessity of
removing any panel, door, or similar obstruction.
Roof jack means that portion of a manufactured home heater flue or
vent assembly, including the cap, insulating means, flashing, and
ceiling plate, located in and above the roof of a manufactured home.
Sealed combustion system appliance means an appliance which by its
inherent design is constructed so that all air supplied for combustion,
the combustion system of the appliance, and all products of combustion
are completely isolated from the atmosphere of the space in which it is
installed.
Water heater means an appliance for heating water for domestic
purposes other than for space heating.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4586, Feb. 12, 1987; 58 FR 55015, Oct. 25, 1993]

Sec. 3280.703 Minimum standards.

Heating, cooling and fuel burning appliances and systems in
manufactured homes shall be free of defects, and shall conform to
applicable standards in the following table unless otherwise specified
in this standard. (See Sec. 3280.4) When more than one standard is
referenced, compliance with any one such standard shall meet the
requirements of this standard.

Appliances

Central Cooling Air Conditioners--UL 465-Seventh Edition-1987 With
Revisions through December 24, 1987.
Liquid Fuel-Burning Heating Appliances for Manufactured Homes and
Recreational Vehicle--UL 307A-Sixth Edition-1990, With Revisions through
August 21, 1990.
Electrical Air Heaters-UL 1025-Second Edition-1987 With Revisions July
13, 1989, February 6, 1990 and December 3, 1991.

[[Page 166]]

Electric Baseboard Heating Equipment--UL 1042-Third Edition-1987 With
Revision July 15, 1993.
Electric Central Air Heating Equipment--UL 1096-Fourth Edition-1986 With
Revisions July 16, 1986 and January 30, 1988.
Gas Burning Heating Appliances for Mobile Homes and Recreational
Vehicles--UL 307B-First Edition-1982 With Revision May 18, 1987.
Gas Clothes Dryers Vol. 1, Type 1 Clothes Dryers--ANSI Z21.5.1-1992.
Gas Fired Absorption Summer Air Conditioning Appliances--ANSI Z21.40.1-
1981, With Addenda Z21.40.1a-1982.
Gas-Fired Central Furnaces [Except Direct Vent System Central
Furnaces]--ANSI Z21.47-1990, With Addendum Z21.47a-1990 and Z21.47b-
1992.
Household Cooking Gas Appliances ANSI Z21.1-1990 With Addenda Z21.1a-
1991 and Z211b-1993.
Refrigerators Using Gas Fuel--ANSI Z21.19-1990, With Addenda Z21.19a-
1992.
Gas Water Heaters Vol. 1, Storage Water Heaters With Input Ratings of
75,000 BTU per hour or Less--ANSI Z21.10.1-1990, With Addendum
Z21.10.1a-1991 and Z21.10.1b-1992.
Household Electric Storage Tank Water Heaters--UL 174-Seventh Edition-
1989 With Revisions May 8, 1990 and January 22, 1991.

Ferrous Pipe and Fittings

Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-
Coated, Welded and Seamless--ASTM A53-93.
Standard Specification for Electric-Resistance-Welded Coiled Steel
Tubing for Gas and Fuel Oil Lines--*ASTM A539-90a.
Pipe Threads, General Purpose (Inch)--ANSI/ASME B1.20.1-1983.
Welding and Seamless Wrought Steel Pipe--ANSI/ASME B36.10-1979.

Nonferrous Pipe, Tubing and Fittings

Standard Specification for Seamless Copper Water Tube--ASTM B88-93.
Standard Specification for Seamless Copper Tube for Air Conditioning and
Refrigeration Field Service--ASTM B280-93.
Metal Connectors for Gas Appliances--ANSI Z21.24-1987, With Addena
Z21.24a 1990 and Z21.24b-1992.
Manually Operated Gas Valves for Appliances, Appliance Connector Valves
and Hose End Valves--ANSI Z21.15-1992.
Standard for Gas Supply Connectors for Manufactured Homes--IAPMO TSC 9-
92.
Standard Specification for General Requirements for Wrought Seamless
Copper and Copper-Alloy Tubes--ASTM B251-93.
Standard Specification for Seamless Copper Pipe, Standard Sizes--ASTM
B42-93.
Direct Vent Central Furnaces--ANSI Z21.64-1990, With Addenda Z21.64a-
1992.

Miscellaneous

Factory-Made Air Ducts and Connectors--UL 181-Seventh Edition-1990, With
Revision November 20, 1990.
Tube Fittings for Flammable and Combustible Fluids, Refrigeration
Service, and Marine Use--UL 109-Fifth Edition-1993.
Pigtails and Flexible Hose Connectors for LP-Gas--UL 569-Sixth Edition-
1990.
Roof Jacks for Manufactured Homes and Recreational Vehicles--UL 311-
Seventh Edition-1990.
Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply
Systems--ANSI Z21.22-1986, With Addenda Z21.22a-1990.
Automatic Gas Ignition Systems and Components--ANSI Z21.20-1989, With
Addendum Z21.20a-1991 and Z21.20b-1992.
Automatic Valves for Gas Appliances--ANSI Z21.21-1987, With Addendum
Z21.21a-1989 and Z21.21b-1992.
Gas Appliance Thermostats--ANSI Z21.23-1989, With Addenda Z21.23a-1991.
Gas Vents--UL 441-Seventh Edition-1991.
Installation of Oil-Burning Equipment, NFPA 31-1992 Edition.
The following sections are applicable:
1-1
1-2
1-3
1-4 except 1-4.1
1-5.1
1-5.2
1-5.4.2
1-5.4.3
1-5.5
1-5.6
1-6
1-7.2 except 1-7.2.4
1-8
1-9
1-10.1
3-1.1
3-1.3
3-1.4
3-1.5
3-1.6
3-10
4-1.3
4-1.4
4-1.5
4-2
4-3 except 4-3.2
4-4 except 4-4.2, 4-4.5.4, 4-4.6
4-4.7, 4-4.9 and 4-4.10 Appendices B, C. and E

National Fuel Gas Code--NFPA 54-1992 ANSI 223.1.
Warm Air Heating and Air Conditioning Systems, 1993 Edition, NFPA-90B.
The following sections are applicable:
2-2.4
2-3.6
Table 3-1.3, Section B
4-1.6

[[Page 167]]

Standard for the Storage and Handling of Liquefied Petroleum Gases, 1992
Edition--NFPA-58.
Flares for Tubing (1972)--SAE-J533b.
Chimneys, Factory-Built Residential Type and Building Heating
Appliance--UL 103-Seventh Edition--1989 With Revision February 23, 1989.
Factory-Built Fireplaces--UL 127-Sixth Edition With Revisions January 4,
1989, June 10, 1991, June 29, 1992.
Room Heaters Solid-Fuel Type--UL 1482--Third Edition--1988 With Revision
September 13, 1988.
Fireplace Stoves--UL 737--Sixth Edition--1988 With Revisions September
19, 1988, July 10, 1990 and June 10, 1991.
Unitary Air-Conditioning and Air-Source Heat Pump Equipment--ANSI/ARI
210/240-89.
AGA Requirements for Gas Connectors for Connection of Fixed Appliances
for Outdoor Installation, Park Trailers and Manufactured (Mobile) Homes
to the Gas Supply--No. 3-87.

[58 FR 55015, Oct. 25, 1993]

Sec. 3280.704 Fuel supply systems.

(a) LP--Gas system design and service line pressure. (1) Systems
shall be of the vapor-withdrawal type.
(2) Gas, at a pressure not over 14 inches water column (\1/2\ psi),
shall be delivered from the system into the gas supply connection.
(b) LP-gas containers--(1) Maximum capacity. No more than two
containers having an individual water capacity of not more than 105
pounds (approximately 45 pounds LP-gas capacity), shall be installed on
or in a compartment of any manufactured home.
(2) Construction of containers. Containers shall be constructed and
marked in accordance with the specifications for LP-Gas Containers of
the U.S. Department of Transportation (DOT) or the Rules for
Construction of Pressure Vessels 1986, ASME Boiler and Pressure Vessel
Code section VIII, Division 1 ASME Containers shall have a design
pressure of at least 312.5 psig.
(i) Container supply systems shall be arranged for vapor withdrawal
only.
(ii) Container openings for vapor withdrawal shall be located in the
vapor space when the container is in service or shall be provided with a
suitable internal withdrawal tube which communicates with the vapor
space on or near the highest point in the container when it is mounted
in service position, with the vehicle on a level surface. Containers
shall be permanently and legibly marked in a conspicuous manner on the
outside to show the correct mounting position and the position of the
service outlet connection. The method of mounting in place shall be such
as to minimize the possibility of an incorrect positioning of the
container.
(3) Location of LP-gas containers and systems. (i) LP-gas containers
shall not be installed, nor shall provisions be made for installing or
storing any LP-gas container, even temporarily, inside any manufactured
home except for listed, completely self-contained hand torches,
lanterns, or similar equipment with containers having a maximum water
capacity of not more than 2\1/2\ pounds (approximately one pound LP-gas
capacity).
(ii) Containers, control valves, and regulating equipment, when
installed, shall be mounted on the ``A'' frame of the manufactured home,
or installed in a compartment that is vaportight to the inside of the
manufactured home and accessible only from the outside. The compartment
shall be ventilated at top and bottom to facilitate diffusion of vapors.
The compartment shall be ventilated with two vents having an aggregate
area of not less than two percent of the floor area of the compartment
and shall open unrestricted to the outside atmosphere. The required
vents shall be equally distributed between the floor and ceiling of the
compartment. If the lower vent is located in the access door or wall,
the bottom edge of the vent shall be flush with the floor level of the
compartment. The top vent shall be located in the access door or wall
with the bottom of the vent not more than 12 inches below the ceiling
level of the compartment. All vents shall have an unrestricted discharge
to the outside atmosphere. Access doors or panels of compartments shall
not be equipped with locks or require special tools or knowledge to
open.
(iii) Permanent and removable fuel containers shall be securely
mounted to prevent jarring loose, slipping or rotating and the
fastenings shall be designed and constructed to withstand static loading
in any direction equal to

[[Page 168]]

twice the weight of the tank and attachments when filled with fuel,
using a safety factor of not less than four based on the ultimate
strength of the material to be used.
(4) LP-gas container valves and accessories. (i) Valves in the
assembly of a two-cylinder system shall be arranged so that replacement
of containers can be made without shutting off the flow of gas to the
appliance(s). This provision is not to be construed as requiring an
automatic change-over device.
(ii) Shutoff valves on the containers shall be protected as follows,
in transit, in storage, and while being moved into final utilization by
setting into a recess of the container to prevent possibility of their
being struck if container is dropped upon a flat surface, or by
ventilated cap or collar, fastened to the container, capable of
withstanding a blow from any direction equivalent to that of a 30-pound
weight dropped 4 feet. Construction shall be such that the blow will not
be transmitted to the valve.
(iii) [Reserved]
(iv) Regulators shall be connected directly to the container shutoff
valve outlets or mounted securely by means of a support bracket and
connected to the container shutoff valve or valves with listed high
pressure connections. If the container is permanently mounted the
connector shall be as required above or with a listed semi-rigid tubing
connector.
(5) LP-gas safety devices. (i) DOT containers shall be provided with
safety relief devices as required by the regulations of the U.S.
Department of Transportation. ASME containers shall be provided with
relief valves in accordance with subsection 221 of the Standard for the
Storage and Handling Liquefied Petroleum Gases, NFPA No. 58-1992. Safety
relief valves shall have direct communication with the vapor space of
the vessel.
(ii) The delivery side of the gas pressure regulator shall be
equipped with a safety relief device set to discharge at a pressure not
less than two times and not more than three times the delivery pressure
of the regulator.
(iii) Systems mounted on the ``A'' frame assembly shall be so
located that the discharge from the safety relief devices shall be into
the open air and not less than three feet horizontally from any opening
into the manufactured home below the level of such discharge.
(iv) Safety relief valves located within liquefied petroleum gas
container compartments may be less than three feet from openings
provided the bottom vent of the compartment is at the same level or
lower than the bottom of any opening into the vehicle, or the
compartment is not located on the same wall plane as the opening(s) and
is at least two feet horizontally from such openings.
(6) LP-gas system enclosure and mounting. (i) Housings and
enclosures shall be designed to provide proper ventilation at least
equivalent to that specified in Sec. 3280.704(b)(3)(ii).
(ii) Doors, hoods, domes, or portions of housings and enclosures
required to be removed or opened for replacement of containers shall
incorporate means for clamping them firmly in place and preventing them
from working loose during transit.
(iii) Provisions shall be incorporated in the assembly to hold the
containers firmly in position and prevent their movement during transit.
(iv) Containers shall be mounted on a substantial support or a base
secured firmly to the vehicle chassis. Neither the container nor its
support shall extend below the manufactured home frame.
(c) Oil tanks--(1) Installation. Oil tanks and listed automatic
pumps (oil lifters) installed for gravity flow of oil to heating
equipment shall be installed so that the top of the tank is no higher
than 8 feet above the appliance oil control and the bottom of the tank
is not less than 18 inches above the appliance oil control.
(2) Auxiliary oil storage tank. Oil supply tanks affixed to a
manufactured home shall be so located as to require filling and draining
from the outside and shall be in a place readily available for
inspection. If the fuel supply tank is located in a compartment of a
manufactured home, the compartment shall be ventilated at the bottom to
permit diffusion of vapors and shall be insulated from the structural
members of the body. Tanks so installed shall be

[[Page 169]]

provided with an outside fill and vent pipe and an approved liquid level
gage.
(3) Shutoff valve. A readily accessible, approved manual shutoff
valve shall be installed at the outlet of an oil supply tank. The valve
shall be installed to close against the supply.
(4) Fuel oil filters. All oil tanks shall be equipped with an
approved oil filter or strainer located downstream from the tank shutoff
valve. The fuel oil filter or strainer shall contain a sump with a drain
for the entrapment of water.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 47 FR 49390, Nov. 1, 1982; 52 FR 4587, Feb. 12, 1987; 58
FR 55016, Oct. 25, 1993]

Sec. 3280.705 Gas piping systems.

(a) General. The requirements of this section shall govern the
installation of all fuel gas piping attached to any manufactured home.
The gas piping supply system shall be designed for a pressure not
exceeding 14 inch water column (\1/2\ psi) and not less than 7 inch
water column (\1/4\ psi). The manufacturer shall indicate in his written
installation instructions the design pressure limitations for safe and
effective operation of the gas piping system. None of the requirements
listed in this section shall apply to the piping supplied as a part of
an appliance. All exterior openings around piping, ducts, plenums or
vents shall be sealed to resist the entrance of rodents.
(b) Materials. All materials used for the installation, extension,
alteration, or repair of any gas piping system shall be new and free
from defects or internal obstructions. It shall not be permissible to
repair defects in gas piping or fittings. Inferior or defective
materials shall be removed and replaced with acceptable material. The
system shall be made of materials having a melting point of not less
than 1,450 F, except as provided in Sec. 3280.705(e). They shall consist
of one or more of the materials described in Sec. 3280.705(b) (1)
through (4).
(1) Steel or wrought-iron pipe shall comply with ANSI Standard
B36.10-1979, Welded and Seamless Wrought Steel Pipe. Threaded brass pipe
in iron pipe sizes may be used. Threaded brass pipe shall comply with
ASTM B43-91, Standard Specification for Seamless Red Brass Pipe,
Standard Sizes.
(2) Fittings for gas piping shall be wrought iron, malleable iron,
steel, or brass (containing not more than 75 percent copper).
(3) Copper tubing shall be anneled type, Grade K or L, conforming to
the Standard Specification for Seamless Copper Water Tube (ASTM B88-93)
or shall comply with the Standard Specification for Seamless Copper Tube
for Air Conditioning and Refrigeration Field Service, ASTM B 280-93.
Copper tubing shall be internally tinned.
(4) Steel tubing shall have a minimum wall thickness of 0.032 inch
for tubing of \1/2\ inch diameter and smaller and 0.049 inch for
diameters \1/2\ inch and larger. Steel tubing shall be constructed in
accordance with ASTM Standard Specification for Electric-Resistance-
Welded Coiled Steel Tubing for Gas and Fuel Oil Lines, ASTM A 539-83,
and shall be externally corrosion protected.
(c) Piping design. Each manufactured home requiring fuel gas for any
purpose shall be equipped with a natural gas piping system acceptable
for LP-gas. Where fuel gas piping is to be installed in more than one
section of an expandable or multiple unit home, the design and
construction of the crossover(s) shall be as follows:
(1) All points of crossover shall be readily accessible from the
exterior of the home.
(2) The connection(s) between units shall be made with a
connector(s) listed for exterior use or direct plumbing sized in
accordance with Sec. 3280.705(d). A shutoff valve of the nondisplaceable
rotor type conforming to ANSI Z21.15-1992 Manually Operated Gas Valves
for Appliances, Appliances Connector Valves and Hose End Valves,
suitable for outdoor use shall be installed at each crossover point
upstream of the connection when listed connectors are used.
(3) The connection(s) may be made by a listed quick disconnect
device which shall be designed to provide a positive seal of the supply
side of the gas system when such device is separated.
(4) The flexible connector, direct plumbing pipe, or ``quick
disconnect''

[[Page 170]]

device shall be provided with protection from mechanical and impact
damage and located to minimize the possibility of tampering.
(5) For gas line cross over connections made with either hard pipe
or flexible connectors, the crossover point(s) shall be capped on the
supply side to provide a positive seal and covered on the other side
with a suitable protective covering.
(6) Suitable protective coverings for the connection device(s) when
separated, shall be permanently attached to the device or flexible
connector.
(7) When a quick disconnect device is installed, a 3 inch by 1\3/4\
inch minimum size tag made of etched, metal-stamped or embossed brass,
stainless steel, anodized or alcalde aluminum not less than 0.020 inch
thick or other approved material (e.g., 0.005 inch plastic laminates)
shall be permanently attached on the exterior wall adjacent to the
access to the ``quick disconnect'' device. Each tag shall be legibly
inscribed with the following information using letters no smaller than
\1/4\ inch high:

Do Not Use Tools To Separate the ``Quick-Disconnect'' Device

(d) Gas pipe sizing. Gas piping systems shall be sized so that the
pressure drop to any appliance inlet connection from any gas supply
connection, when all appliances are in operation at maximum capacity, is
not more than 0.5 inch water column as determined on the basis of test,
or in accordance with table 3280.705(d). When determining gas pipe
sizing in the table, gas shall be assumed to have a specific gravity of
0.65 and rated at 1000 B.T.U. per cubic foot. The natural gas supply
connection(s) shall be not less than the size of the gas piping but
shall be not smaller than \3/4\ inch nominal pipe size.
(e) Joints for gas pipe. All pipe joints in the piping system,
unless welded or brazed, shall be threaded joints that comply with Pipe
Threads, General Purpose (Inch), adopted 25 October 1984, ANSI/ASME
B1.20.1-1983. Right and left nipples or couplings shall not be used.
Unions, if used, shall be of ground joint type. The material used for
welding or brazing pipe connections shall have a melting temperature in
excess of 1,000 F.
(f) Joints for tubing. (1) Tubing joints shall be made with either a
single or a double flare of 45 degrees in accordance with Flares For
Tubing, SAE-J533b-1972 or with other listed vibration-resistant
fittings, or joints may be brazed with material having a melting point
exceeding 1,000 F. Metallic ball sleeve compression-type tubing fittings
shall not be used.
(2) Steel tubing joints shall be made with a double-flare in
accordance with Flares For Tubing, SAE-J533b-1972.
(g) Pipe joint compound. Screw joints shall be made up tight with
listed pipe joint compound, insoluble in liquefied petroleum gas, and
shall be applied to the male threads only.
(h) Concealed tubing. Tubing shall not be run inside walls, floors,
partitions, or roofs. Where tubing passes through walls, floors,
partitions, roofs, or similar installations, such tubing shall be
protected by the use of weather resistant grommets that shall snugly fit
both the tubing and the hole through which the tubing passes.

[[Page 171]]

Part I--Maximum Capacity of Different Sizes of Pipe and Tubing in Thousands of Btu's Per Hour of Natural Gas For Gas Pressures of 0.5 Psig or Less and a
Maximum Pressure Drop of \1/2\ Inch Water Column
--------------------------------------------------------------------------------------------------------------------------------------------------------
Iron pipe sizes--Length in feet Tubing--Length in feet
--------------------------------------------------------------------------------------------------------------------------------------------------------
I.D. 10 20 30 40 50 60 70 80 90 100 O.D. 10 20 30 40 50 60 70 80 90 100
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1/ 43 29 24 20 18 16 15 14 13 12 \3/ 27 18 15 13 11 10 9 9 8 8
4\" 8\"
\3/ 95 65 52 45 40 36 33 31 29 27 \1/ 56 38 31 26 23 21 19 18 17 16
8\" 2\"
\1/ 175 120 97 82 73 66 61 57 53 50 \5/ 113 78 62 53 47 43 39 37 34 33
2\" 8\"
\3/ 360 250 200 170 151 138 125 118 110 103 \3/ 197 136 109 93 83 75 69 64 60 57
4\" 4\"
1" 680 465 375 320 285 260 240 220 215 195 \7/ 280 193 155 132 117 106 98 91 85 81
8\"
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 172]]

Part II [Reserved]

(i) Concealed joints. Piping or tubing joints shall not be located
in any floor, wall partition, or similar concealed construction space.
(j) Gas supply connections. When gas appliances are installed, at
least one gas supply connection shall be provided on each home. The
connection shall not be located beneath an exit door. Where more than
one connection is provided, the piping system shall be sized to provide
adequate capacity from each supply connection.
(k) Identification of gas supply connections. Each manufactured home
shall have permanently affixed to the exterior skin at or near each gas
supply connection or the end of the pipe, a tag of 3 inches by 1\3/4\
inches minimum size, made of etched, metal-stamped or embossed brass,
stainless steel, anodized or alcalde aluminum not less than 0.020 inch
thick, or other approved material (e.g., 0.005 inch plastic laminates),
which reads as follows. The connector capacity indicated on this tag
shall be equal to or greater than the total Btuh rating of all intended
gas appliances.

------------------------------------------------------------------
Combination LP-Gas and Natural Gas System
This gas piping system is designed for use of
either liquefied petroleum gas or natural gas.
NOTICE: BEFORE TURNING ON GAS BE CERTAIN APPLIANCES
ARE DESIGNED FOR THE GAS CONNECTED AND ARE EQUIPPED WITH
CORRECT ORIFICES. SECURELY CAP THIS INLET WHEN NOT CONNECTED
FOR USE.
When connecting to lot outlet, use a listed gas
supply connector for mobile homes rated at {time} 100,000
Btuh or more; {time} 250,000 Btuh or more.
Before turning on gas, make certain all gas
connections have been made tight, all appliance valves are
turned off, and any unconnected outlets are capped.
After turning on gas, test gas piping and
connections to appliances for leakage with soapy water or
bubble solution, and light all pilots.

------------------------------------------------------------------

The connector capacity indicated on this tag shall be equal to or
greater than the total Btuh rating of all intended gas appliances.
(l) LP-gas supply connectors. (1) A listed LP-gas flexible
connection conforming to the UL Standard for Pigtails, and Flexible Hose
Connectors for LP-Gas, UL 569--Sixth Edition--1990, or equal shall be
supplied when LP-gas cylinder(s) and regulator(s) are supplied.
(2) Appliance connections. All gas burning appliances shall be
connected to the fuel piping. Materials as provided in Sec. 3280.705(b)
or listed appliance connectors shall be used. Listed appliance
connectors when used shall not run through walls, floors, ceilings or
partitions, except for cabinetry, and shall be 3 feet or less in length
or 6 feet or less for cooking appliances. Connectors of aluminum shall
not be used outdoors. A manufactured home containing a combination LP-
natural-gas-system may be provided with a gas outlet to supply exterior
appliances when installed in accordance with the following:
(i) No portion of the completed installation shall project beyond
the wall of the manufactured home.
(ii) The outlet shall be provided with an approved quick-disconnect
device, which shall be designed to provided a positive seal on the
supply side of the gas system when the appliance is disconnected. A
shutoff valve of the nondisplaceable rotor type conforming to ANSI
Z21.15-1992, Manually Operated Gas Valves, shall be installed
immediately upstream of the quick-disconnect device. The complete device
shall be provided as part of the original installation.
(iii) Protective caps or plugs for the ``quick-disconnect'' device,
when disconnected, shall be permanently attached to the manufactured
home adjacent to the device.
(iv) A tag shall be permanently attached to the outside of the
exterior wall of the manufactured home as close

[[Page 173]]

as possible to the gas supply connection. The tag shall indicate the
type of gas and the Btuh capacity of the outlet and shall be legibly
inscribed as follows:

THIS OUTLET IS DESIGNED FOR USE WITH GAS PORTABLE APPLIANCES WHOSE
TOTAL INPUT DO NOT EXCEED ------ BTUH. REPLACE PROTECTIVE COVERING OVER
CONNECTOR WHEN NOT IN USE.

(3) Valves. A shutoff valve shall be installed in the fuel piping at
each appliance inside the manufactured home structure, upstream of the
union or connector in addition to any valve on the appliance and so
arranged to be accessible to permit serving of the appliance and removal
of its components. The shutoff valve shall be located within 6 feet of a
cooking appliance and within 3 feet of any other appliance. A shutoff
valve may serve more than one appliance if located as required above.
Shut off valves shall be of the nondisplaceable rotor type and conform
ANSI Z21.15-1992, Manually Operated Gas Valves.
(4) Gas piping system openings. All openings in the gas piping
system shall be closed gas-tight with threaded pipe plugs or pipe caps.
(5) Electrical ground. Gas piping shall not be used for an
electrical ground.
(6) Couplings. Pipe couplings and unions shall be used to join
sections of threaded piping. Right and left nipples or couplings shall
not be used.
(7) Hangers and supports. All gas piping shall be adequately
supported by galvanized or equivalently protected metal straps or
hangers at intervals of not more than 4 feet, except where adequate
support and protection is provided by structural members. Solid-iron-
pipe gas supply connection(s) shall be rigidly anchored to a structural
member within 6 inches of the supply connection(s).
(8) Testing for leakage. (i) Before appliances are connected, piping
systems shall stand a pressure of at least six inches mercury or three
PSI gage for a period of not less than ten minutes without showing any
drop in pressure. Pressure shall be measured with a mercury manometer or
slope gage calibrated so as to be read in increments of not greater than
one-tenth pound, or an equivalent device. The source of normal operating
pressure shall be isolated before the pressure tests are made. Before a
test is begun, the temperature of the ambient air and of the piping
shall be approximately the same, and constant air temperature be
maintained throughout the test.
(ii) After appliances are connected, the piping system shall be
pressurized to not less than 10 inches nor more than 14 inches water
column and the appliance connections tested for leakage with soapy water
or bubble solution.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 54383, Oct. 5, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 52 FR 4587,
Feb. 12, 1987; 58 FR 55016, Oct. 25, 1993]

Sec. 3280.706 Oil piping systems.

(a) General. The requirements of this section shall govern the
installation of all liquid fuel piping attached to any manufactured
home. None of the requirements listed in this section shall apply to the
piping in the appliance(s).
(b) Materials. All materials used for the installation extension,
alteration, or repair, of any oil piping systems shall be new and free
from defects or internal obstructions. The system shall be made of
materials having a melting point of not less than 1,450 F, except as
provided in Sec. 280.706(d) and (e). They shall consist of one or more
of the materials described in Sec. 3280.706(b) (1) through (4).
(1) Steel or wrought-iron pipe shall comply with ANSI B 36.10-1979,
Welded and Seamless Wrought Steel Pipe. Threaded copper or brass pipe in
iron pipe sizes may be used.
(2) Fittings for oil piping shall be wrought-iron, malleable iron,
steel, or brass (containing not more than 75 percent copper).
(3) Copper tubing shall be annealed type, Grade K or L conforming to
the Standard Specification for Seamless Copper Water Tube, ASTM B88-93,
or shall comply with the Standard Specification for Seamless Copper Tube
for Air Conditioning and Refrigeration Field Service, ASTM B280-93.
(4) Steel tubing shall have a minimum wall thickness of 0.032 inch
for diameters up to \1/2\ inch and 0.049 inch for diameters \1/2\ inch
and larger. Steel

[[Page 174]]

tubing shall be constructed in accordance with the Specification for
Electric-Resistance-Welded Coiled Steel Tubing for Gas and Field Oil
Lines, ASTM, A539-90a, and shall be externally corrosion protected.
(c) Size of oil piping. The minimum size of all fuel oil tank piping
connecting outside tanks to the appliance shall be no smaller than \3/8\
inch OD copper tubing or \1/4\ inch IPS. If No. 1 fuel oil is used with
a listed automatic pump (fuel lifter), copper tubing shall be sized as
specified by the pump manufacturer.
(d) Joints for oil piping. All pipe joints in the piping system,
unless welded or brazed, shall be threaded joints which comply with
ANSI/ASME B1.20.1-1983, Pipe Threads, General Purpose (Inch). The
material used for brazing pipe connections shall have a melting
temperature in excess of 1,000 F.
(e) Joints for tubing. Joints in tubing shall be made with either a
single or double flare of the proper degree, as recommended by the
tubing manufacturer, by means of listed tubing fittings, or brazed with
materials having a melting point in excess of 1,000 F.
(f) Pipe joint compound. Threaded joints shall be made up tight with
listed pipe joint compound which shall be applied to the male threads
only.
(g) Couplings. Pipe couplings and unions shall be used to join
sections of threaded pipe. Right and left nipples or couplings shall not
be used.
(h) Grade of piping. Fuel oil piping installed in conjunction with
gravity feed systems to oil heating equipment shall slope in a gradual
rise upward from a central location to both the oil tank and the
appliance in order to eliminate air locks.
(i) Strap hangers. All oil piping shall be adequately supported by
galvanized or equivalently protected metal straps or hangers at
intervals of not more than 4 feet, except where adequate support and
protection is provided by structural members. Solid-iron-pipe oil supply
connection(s) shall be rigidly anchored to a structural member within 6
inches of the supply connection(s).
(j) Testing for leakage. Before setting the system in operation,
tank installations and piping shall be checked for oil leaks with fuel
oil of the same grade that will be burned in the appliance. No other
material shall be used for testing fuel oil tanks and piping. Tanks
shall be filled to maximum capacity for the final check for oil leakage.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4588, Feb. 12, 1987; 58 FR 55017, Oct. 25, 1993]

Sec. 3280.707 Heat producing appliances.

(a) Heat-producing appliances and vents, roof jacks and chimneys
necessary for their installation in manufactured homes shall be listed
or certified by a nationally recognized testing agency for use in
manufactured homes.
(1) A manufactured home shall be provided with a comfort heating
system.
(i) When a manufactured home is manufactured to contain a heating
appliance, the heating appliance shall be installed by the manufacturer
of the manufactured home in compliance with applicable sections of this
subpart.
(ii) When a manufactured home is manufactured for field application
of an external heating or combination heating/cooling appliance,
preparation of the manufactured home for this external application shall
comply with the applicable sections of this part.
(2) Gas and oil burning comfort heating appliances shall have a flue
loss of not more than 25 percent, and a thermal efficiency of not less
than that specified in nationally recognized standards (See
Sec. 3280.703).
(b) Fuel-burning heat-producing appliances and refrigeration
appliances, except ranges and ovens, shall be of the vented type and
vented to the outside.
(c) Fuel-burning appliances shall not be converted from one fuel to
another fuel unless converted in accordance with the terms of their
listing and the appliance manufacturer's instructions.
(d) Performance efficiency. (1) All automatic electric storage water
heaters installed in manufactured homes shall have a standby loss not
exceeding 43 watts/meter\2\ (4 watts/ft\2\) of tank surface area. The
method of test for standby loss shall be as described in section 4.3.1
of Household Automatic

[[Page 175]]

Electric Storage Type Water Heaters, ANSI C72.1-1972.
(2) All gas and oil-fired automatic storage water heaters shall have
a recovery efficiency, E, and a standby loss, S, as described below. The
method of test of E and S shall be as described in section 2.7 of Gas
Water heaters, Vol. I, Storage Water Heaters with Input/Ratings of
75,000 BTU per hour or less, ANSI Z21.10.1-1990, with addendums
Z21.10.1a-1991 and Z21.10.1b-1992 except that for oil-fired units.
CF=1.0, Q=total gallons of oil consumed and H=total heating value of oil
in BTU/gallon.

------------------------------------------------------------------------
Recovery
Storage capacity in gallons efficiency Standby loss
------------------------------------------------------------------------
Less than 25.................... At least 75 Not more than 7.5
percent. percent.
25 up to 35..................... 00................ Not more than 7
percent.
35 or more...................... 00................ Not more than 6
percent.
------------------------------------------------------------------------

(e) Each space heating, cooling or combination heating and cooling
system shall be provided with at least one readily adjustable automatic
control for regulation of living space temperature. The control shall be
placed a minimum of 3 feet from the vertical edge of the appliance
compartment door. It shall not be located on an exterior wall or on a
wall separating the appliance compartment from a habitable room.
(f) Oil-fired heating equipment. All oil-fired heating equipment
shall conform to liquid fuel-burning heating appliances for UL 307A--
Fifth Edition--1987, Liquid Fuel-Burning Heating Appliances for Mobile
Homes and Recreational Vehicles, and be installed in accordance with
Installation of Oil Burning Equipment, NFPA 31-1983. Regardless of the
requirements of the above referenced standards, or any other referenced
standards, the following are not required:
(1) External switches or remote controls which shut off the burner
or the flow of oil to the burner, or
(2) An emergency disconnect switch to interrupt electric power to
the equipment under conditions of excessive temperature.

[40 FR 58752, Dec. 17, 1975, as amended at 42 FR 54383, Oct. 5, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 47 FR 49391,
Nov. 1, 1982; 52 FR 4588, Feb. 12, 1987; 52 FR 47553, Dec. 15, 1987; 58
FR 55017, Oct. 25, 1993]

Sec. 3280.708 Exhaust duct system and provisions for the future installation of a clothes dryer.

(a) Clothes dryers. (1) All gas and electric clothes dryers shall be
exhausted to the outside by a moisture-lint exhaust duct and termination
fitting. When the clothes dryer is supplied by the manufacturer, the
exhaust duct and termination fittings shall be completely installed by
the manufacturer. However, if the exhaust duct system is subject to
damage during transportation, it need not be completely installed at the
factory when:
(i) The exhaust duct system is connected to the clothes dryer, and
(ii) A moisture lint exhaust duct system is roughed in and
installation intructions are provided in accordance with paragraph
(b)(3) or (c) of this section.
(2) A clothes dryer moisture-lint exhaust duct shall not be
connected to any other duct, vent or chimney.
(3) The exhaust duct shall not terminate beneath the manufactured
home.
(4) Moisture-lint exhaust ducts shall not be connected with sheet
metal screws or other fastening devices which extend into the interior
of the duct.
(5) Moisture-lint exhaust duct and termination fittings shall be
installed in accordance with the appliance manufacturer's printed
instructions.
(b) Provisions for future intallation of a gas clothes dryer. A
manufactured home may be provided with ``stubbed in'' equipment at the
factory to supply a gas clothes dryer for future installation by the
owner provided it complies with the following provisions:
(1) The ``stubbed in'' gas outlet shall be provided with a shutoff
valve, the outlet of which is closed by threaded pipe plug or cap;
(2) The ``stubbed in'' gas outlet shall be permanently labeled to
identify it

[[Page 176]]

for use only as the supply connection for a gas clothes dryer;
(3) A moisture lint duct system consisting of a complete access
space (hole) through the wall or floor cavity with a cap or cover on the
interior and exterior of the cavity secured in such a manner that they
can be removed by a common household tool shall be provided. The cap or
cover in place shall limit air infiltration and be designed to resist
the entry of water or rodents. The manufacturer is not required to
provide the moisture-lint exhaust duct or the termination fitting. The
manufacturer shall provide written instructions to the owner on how to
complete the exhaust duct installation in accordance with provisions of
Sec. 3280.708(a)(1) through (5).
(c) Provisions for future installation of a electric clothes dryers.
When wiring is installed to supply an electric clothes dryer for future
installation by the owner, the manufacturer shall:
(1) Provide a roughed in moisture-lint exhaust duct system
consisting of a complete access space (hole) through the wall or floor
cavity with a cap or cover on the interior and exterior of the cavity
which are secured in such a manner that they can be removed by the use
of common household tools. The cap or cover in place shall limit air
filtration and be designed to resist the entry of water or rodents into
the home. The manufacturer is not required to provide the moisture-lint
exhaust duct or the termination fitting;
(2) Install a receptacle for future connection of the dryer;
(3) Provide written instructions on how to complete the exhaust duct
installation in accordance with the provisions of paragraphs (a)(1)
through (5) of this section.

[42 FR 54383, Oct. 5, 1977. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55018, Oct. 25, 1993]

Sec. 3280.709 Installation of appliances.

(a) The installation of each appliance shall conform to the terms of
its listing and the manufacturer's instructions. The installer shall
leave the manufacturer's instructions attached to the appliance. Every
appliance shall be secured in place to avoid displacement. For the
purpose of servicing and replacement, each appliance shall be both
accessible and removable.
(b) Heat-producing appliances shall be so located that no doors,
drapes, or other such material can be placed or swing closer to the
front of the appliance than the clearances specified on the labeled
appliances.
(c) Clearances surrounding heat producing appliances shall not be
less than the clearances specified in the terms of their listings.
(1) Prevention of storage. The area surrounding heat producing
appliances installed in areas with interior or exterior access shall be
framed-in or guarded with noncombustible material such that the distance
from the appliance to the framing or guarding material is not greater
than three inches unless the appliance is installed in compliance with
paragraph (c)(2), of this section. When clearance required by the
listing is greater than three inches, the guard or frame shall not be
closer to the appliance than the distance provided in the listing.
(2) Clearance spaces surrounding heat producing appliances are not
required to be framed-in or guarded when:
(i) A space is designed specifically for a clothes washer or dryer;
(ii) Dimensions surrounding the appliance do not exceed three
inches; or
(iii) The manufacturer affixes either to a side of an alcove or
compartment containing the appliance, or to the appliance itself, in a
clearly visible location, a 3" x 5" adhesive backed plastic laminated
label or the equivalent which reads as follows:

``Warning''

This compartment is not to be used as a storage area. Storage of
combustible materials or containers on or near any appliance in this
compartment may create a fire hazard. Do not store such materials or
containers in this compartment.

(d) All fuel-burning appliances, except ranges, ovens, illuminating
appliances, clothes dryers, solid fuel-burning fireplaces and solid
fuel-burning fireplace stoves, shall be installed to provide for the
complete separation of the combustion system from the interior
atmosphere of the manufactured home. Combustion air inlets and flue gas
outlets shall be listed or certified

[[Page 177]]

as components of the appliance. The required separation may be obtained
by:
(1) The installation of direct vent system (sealed combustion
system) appliances, or
(2) The installation of appliances within enclosures so as to
separate the appliance combustion system and venting system from the
interior atmosphere of the manufactured home. There shall not be any
door, removable access panel, or other opening into the enclosure from
the inside of the manufactured home. Any opening for ducts, piping,
wiring, etc., shall be sealed.
(e) A forced air appliance and its return-air system shall be
designed and installed so that negative pressure created by the air-
circulating fan cannot affect its or another appliance's combustion air
supply or act to mix products of combustion with circulating air.
(1) The air circulating fan of a furnace installed in an enclosure
with another fuel-burning appliance shall be operable only when any door
or panel covering an opening in the furnace fan compartment or in a
return air plenum or duct is in the closed position. This does not apply
if both appliances are direct vent system (sealed combustion system)
appliances.
(2) If a warm air appliance is installed within an enclosure to
conform to Sec. 3280.709(d)(2), each warm-air outlet and each return air
inlet shall extend to the exterior of the enclosure. Ducts, if used for
that purpose, shall not have any opening within the enclosure and shall
terminate at a location exterior to the enclosure.
(3) Cooling coils installed as a portion of, or in connection with,
any forced-air furnace shall be installed on the downstream side unless
the furnace is specifically otherwise listed.
(4) An air conditioner evaporator section shall not be located in
the air discharge duct or plenum of any forced-air furnace unless the
manufactured home manufacturer has complied with certification required
in Sec. 3280.511.
(5) If a cooling coil is installed with a forced-air furnace, the
coil shall be installed in accordance with its listing. When a furnace-
coil unit has a limited listing, the installation must be in accordance
with that listing.
(6) When an external heating appliance or combination cooling/
heating appliance is to be field installed, the home manufacturer shall
make provision for proper location of the connections to the supply and
return air systems. The manufacturer is not required to provide said
appliance(s). The preparation by the manufacturer for connection to the
home's supply and return air system shall include all fittings and
connection ducts to the main duct and return air system such that the
installer is only required to provide:
(i) The appliance;
(ii) Any appliance connections to the home; and
(iii) The connecting duct between the external appliance and the
fitting installed on the home by the manufacturer. The above connection
preparations by the manufacturer do not apply to supply or return air
systems designed only to accept external cooling (i.e., self contained
air conditioning systems, etc.)
(7) The installation of a self contained air conditioner comfort
cooling appliance shall meet the following requirements:
(i) The installation on a duct common with an installed heating
appliance shall require the installation of an automatic damper or other
means to prevent the cooled air from passing through the heating
appliance unless the heating appliance is certified or listed for such
application and the supply system is intended for such an application.
(ii) The installation shall prevent the flow of heated air into the
external cooling appliance and its connecting ducts to the manufactured
home supply and return air system during the operation of the heating
appliance installed in the manufactured home.
(iii) The installation shall prevent simultaneous operation of the
heating and cooling appliances.
(f) Vertical clearance above cooking top. Ranges shall have a
vertical clearance above the cooking top of not less than 24 inches.
(See Sec. 3280.204).
(g) Solid fuel-burning factory-built fireplaces and fireplace stoves
listed for use in manufactured homes may be

[[Page 178]]

installed in manufactured homes provided they and their installation
conform to the following paragraphs. A fireplace or fireplace stove
shall not be considered as a heating facility for determining compliance
with subpart F.
(1) A solid fuel-burning fireplace or fireplace stove shall be
equipped with integral door(s) or shutter(s) designed to close the
fireplace or fireplace stove fire chamber opening and shall include
complete means for venting through the roof, a combustion air inlet, a
hearth extension, and means to securely attach the fireplace or the
fireplace stove to the manufactured home structure. The installation
shall conform to the following paragraphs (g)(1) (i) to (vii) inclusive:
(i) A listed factory-built chimney designed to be attached directly
to the fireplace or fireplace stove shall be used. The listed factory
built chimney shall be equipped with and contain as part of its listing
a termination device(s) and a spark arrester(s).
(ii) A fireplace or fireplace stove, air intake assembly, hearth
extension and the chimney shall be installed in accordance with the
terms of their listings and their manufacturer's instructions.
(iii) The combustion air inlet shall conduct the air directly into
the fire chamber and shall be designed to prevent material from the
hearth dropping onto the area beneath the manufactured home.
(iv) The fireplace or fireplace stove shall not be installed in a
sleeping room.
(v) Hearth extension shall be of noncombustible material not less
than \3/8\-inch thick. The hearth shall extend at least 16 inches in
front or and at least 8 inches beyond each side of the fireplace or
fireplace stove opening. Furthermore the hearth shall extend over the
entire surface beneath a fireplace stove and beneath an elevated or
overhanging fireplace.
(vi) The label on each solid fuel-burning fireplace and solid fuel-
burning fireplace stove shall include the following wording: For use
with solid fuel only.
(vii) The chimney shall extend at least three feet above the part of
the roof through which it passes and at least two feet above the highest
elevation of any part of the manufactured home within 10 feet of the
chimney. Portions of the chimney and termination that exceed an
elevation of 13\1/2\ ft. above ground level may be designed to be
removed for transporting the manufactured home.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 44 FR 66195, Nov. 19, 1979; 58 FR 55018, Oct. 25, 1993]

Sec. 3280.710 Venting, ventilation and combustion air.

(a) The venting as required by Sec. 3280.707(b) shall be
accomplished by one or more of the methods given in (a)(1) and (2) of
this section:
(1) An integral vent system listed or certified as part of the
appliance.
(2) A venting system consisting entirely of listed components,
including roof jack, installed in accordance with the terms of the
appliance listing and the appliance manufacturer's instructions.
(b) Venting and combustion air systems shall be installed in
accordance with the following:
(1) Components shall be securely assembled and properly aligned at
the factory in accordance with the appliance manufacturer's instructions
except vertical or horizontal sections of a fuel fired heating appliance
venting system that extend beyond the roof line or outside the wall line
may be installed at the site. Sectional venting systems shall be listed
for such applications and installed in accordance with the terms of
their listings and manufacturers' instructions. In cases where sections
of the venting system are removed for transportation, a label shall be
permanently attached to the appliance indicating the following:

Sections of the venting system have not been installed. Warning-do
not operate the appliance until all sections have been assembled and
installed in accordance with the manufacturer's instructions.

(2) Draft hood connectors shall be firmly attached to draft hood
outlets or flue collars by sheet metal screws or by equivalent effective
mechanical fasteners.
(3) Every joint of a vent, vent connector, exhaust duct and
combustion

[[Page 179]]

air intake shall be secure and in alignment.
(c) Venting systems shall not terminate underneath a manufactured
home.
(d) Venting system terminations shall be not less than three feet
from any motor-driven air intake discharging into habitable areas.
(e) The area in which cooking appliances are located shall be
ventilated by a metal duct which may be single wall, not less than 12.5
square inches in cross-sectional area (minimum dimension shall be two
inches) located above the appliance(s) and terminating outside the
manufactured home, or by listed mechanical ventilating equipment
discharging outside the home, that is installed in accordance with the
terms of listing and the manufacturer's instructions. Gravity or
mechanical ventilation shall be installed within a horizontal distance
of not more than ten feet from the vertical front of the appliance(s).
(f) Mechanical ventilation which exhausts directly to the outside
atmosphere from the living space of a home shall be equipped with an
automatic or manual damper. Operating controls shall be provided such
that mechanical ventilation can be separately operated without directly
energizing other energy consuming devices.

[49 FR 32012, Aug. 9, 1984, as amended at 58 FR 55018, Oct. 25, 1993]

Sec. 3280.711 Instructions.

Operating instructions shall be provided with each appliance. These
instructions shall include directions and information covering the
proper use and efficient operation of the appliance and its proper
maintenance.

Sec. 3280.712 Marking.

(a) Information on clearances, input rating, lighting and shutdown
shall be attached to the appliances with the same permanence as the
nameplate, and so located that it is easily readable when the appliance
is properly installed or shutdown for transporting of manufactured home.
(b) Each fuel-burning appliance shall bear permanent marking
designating the type(s) of fuel for which it is listed.

Sec. 3280.713 Accessibility.

Every appliance shall be accessible for inspection, service, repair,
and replacement without removing permanent construction. For those
purposes, inlet piping supplying the appliance shall not be considered
permanent construction. Sufficient room shall be available to enable the
operator to observe the burner, control, and ignition means while
starting the appliance.

[58 FR 55018, Oct. 25, 1993]

Sec. 3280.714 Appliances, cooling.

(a) Every air conditioning unit or a combination air conditioning
and heating unit shall be listed or certified by a nationally recognized
testing agency for the application for which the unit is intended and
installed in accordance with the terms of its listing.
(1) Mechanical air conditioners shall be rated in accordance with
the ARI Standard 210/240-89 Unitary Air Conditioning and Air Source
Unitary Heat Pump Equipment and certified by ARI or other nationally
recognized testing agency capable of providing follow-up service.
(i) Electric motor-driven unitary cooling systems with rated
capacity less than 65,000 BTU/Hr when rated at ARI Standard rating
conditions in ARI Standard 210/240-89 Unitary Air-Conditioning and Air-
Source Heat Pump Equipment, shall show energy efficiency (EER) values
not less than 7.2.
(ii) Heat pumps shall be certified to comply with all the
requirements of the ARI Standard 210/240-89 Unitary Air Conditioning and
Air Source Unitary Heat Pump Equipment. Electric motor-driven vapor
compression heat pumps with supplemental electrical resistance heat
shall be sized to provide by compression at least 60 percent of the
calculated annual heating requirements for the manufactured home being
served. A control shall be provided and set to prevent operation of
supplemental electrical resistance heat at outdoor temperatures above 40
F, except for defrost operation.
(iii) Electric motor-driven vapor compression heat pumps with
supplemental electric resistance heat conforming to ARI Standard 210/
240-89 Unitary Air-Conditioning and Air-Source

[[Page 180]]

Heat Pump Equipment shall show coefficient of performance ratios not
less than shown below:

COP
------------------------------------------------------------------------
Coefficient
Temperature degrees fahrenheit of
performance
------------------------------------------------------------------------
47........................................................ 2.5
17........................................................ 1.7
0......................................................... 1.0
------------------------------------------------------------------------

(2) Gas-fired absorption air conditioners shall be listed or
certified in accordance with ANSI Standard Z21.40.1-1981 ``Gas-fired
Absorption Summer Air Conditioning Appliances'' with addenda la-1982,
and certified by a nationally recognized testing agency capable of
providing follow-up service.
(3) Direct refrigerating systems serving any air conditioning or
comfort-cooling system installed in a manufactured home shall employ a
type of refrigerant that ranks no lower than Group 5 in the
Underwriters' Laboratories, Inc. ``Classification of Comparative Life
Hazard of Various Chemicals.''
(4) When a cooling or heat pump coil and air conditioner blower are
installed with a furnace or heating appliance, they shall be tested and
listed in combination for heating and safety performance by a nationally
recognized testing agency.
(5) Cooling or heat pump indoor coils and outdoor sections shall be
certified, listed and rated in combination for capacity and efficiency
by a nationally recognized testing agency(ies). Rating procedures shall
be based on U.S. Department of Energy test procedures.
(b) Installation and instructions. (1) The installation of each
appliance shall conform to the terms of its listing as specified on the
appliance and in the manufacturer's instructions. The installer shall
include the manufacturer's installation instructions in the manufactured
home. Appliances shall be secured in place to avoid displacement and
movement from vibration and road shock.
(2) Operating instructions shall be provided with the appliance.
(c) Fuel-burning air conditioners shall also comply with
Sec. 280.707.
(d) The appliance rating plate shall be so located that it is easily
readable when the appliance is properly installed.
(e) Every installed appliance shall be accessible for inspection,
service, repair and replacement without removing permanent construction.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55018, Oct. 25, 1993]

Sec. 3280.715 Circulating air systems.

(a) Supply system. (1) Supply ducts and any dampers contained
therein shall be made from galvanized steel, tin-plated steel, or
aluminum, or shall be listed Class 0, Class 1, or Class 2 air ducts.
Class 2 air ducts shall be located at least 3 feet from the furnace
bonnet or plenum. A duct system integral with the structure shall be of
durable construction that can be demonstrated to be equally resistant to
fire and deterioration. Ducts constructed from sheet metal shall be in
accordance with the following table:

Minimum Metal Thickness for Ducts \1\
------------------------------------------------------------------------
Diameter Width
Duct type 14 in. or over 14
less in.
------------------------------------------------------------------------
Round............................................. 0.013 0.016
Enclosed rectangular.............................. .013 .016
Exposed rectangular............................... .016 .019
------------------------------------------------------------------------
\1\ When ``nominal'' thicknesses are specified, 0.003 in. shall be added
to these ``minimum'' metal thicknesses.

(2) Sizing of ducts for heating. (i) Ducts shall be so designed that
when a labeled forced-air furnace is installed and operated continuously
at its normal heating air circulating rate in the manufactured home,
with all registers in the full open position, the static pressure
measured in the casing shall not exceed 90% of that shown on the label
of the appliance. For upflow furnaces the static pressure shall be taken
in the duct plenum. For external heating or combination heating/cooling
appliances the static pressure shall be taken at the point used by the
agency listing or certifying the appliance.
(ii) When an evaporator-coil specifically designed for the
particular furnace is installed between the furnace and the duct plenum,
the total static pressure shall be measured downstream of the coil in
accordance with the appliance label and shall not exceed 90

[[Page 181]]

percent of that shown on the label of the appliance.
(iii) When any other listed air-cooler coil is installed between the
furnace and the duct plenum, the total static pressure shall be measured
between the furnace and the coil and it shall not exceed 90 percent of
that shown on the label of the furnace.
(iv) The minimum dimension of any branch duct shall be at least 1\1/
2\ inches, and of any main duct, 2\1/2\ inches.
(3) Sizing of ducts. (i) The manufactured home manufacturer shall
certify the capacity of the air cooling supply duct system for the
maximum allowable output of ARI certified central air conditioning
systems. The certification shall be at operating static pressure of 0.3
inches of water or greater. (See Sec. 3280.511).
(ii) The refrigerated air cooling supply duct system including
registers must be capable of handling at least 300 cfm per 10,000 btuh
with a static pressure no greater than 0.3 inches of water when measured
at room temperature. In the case of application of external self
contained comfort cooling appliances or the cooling mode of combination
heating/cooling appliances, either the external ducts between the
appliance and the manufactured home supply system shall be considered
part of, and shall comply with the requirements for the refrigerated air
cooling supply duct system, or the connecting duct between the external
appliance and the mobile supply duct system shall be a part of the
listed appliance. The minimum dimension of any branch duct shall be at
least 1\1/2\ inches, and of any main duct, 2\1/2\ inches.
(4) Airtightness of supply duct systems. A supply duct system shall
be considered substantially airtight when the static pressure in the
duct system, with all registers sealed and with the furnace air
circulator at high speed, is at least 80 percent of the static pressure
measured in the furnace casing, with its outlets sealed and the furnace
air circulator operating at high speed. For the purpose of this
paragraph and Sec. 3280.715(b) pressures shall be measured with a water
manometer or equivalent device calibrated to read in increments not
greater than \1/10\ inch water column.
(5) Expandable or multiple manufactured home connections. (i) An
expandable or multiple manufactured home may have ducts of the heating
system installed in the various units. The points of connection must be
so designed and constructed that when the manufactured home is fully
expanded or coupled, the resulting duct joint will conform to the
requirements of this part.
(ii) Installation instructions for supporting the crossover duct
from the manufactured home shall be provided for onsite installation.
The duct shall not be in contact with the ground.
(6) Air supply ducts shall be insulated with material having an
effective thermal resistance (R) of not less than 4.0 unless they are
within manufactured home insulation having a minimum effective value of
R-4.0 for floors or R-6.0 for ceilings.
(7) Supply and return ducts exposed directly to outside air, such as
under chassis crossover ducts or ducts connecting external heating,
cooling or combination heating/cooling appliances shall be insulated
with material having a minimum thermal resistance of R=4.0, with a
continuous vapor barrier having a perm rating of not more than 1 perm.
Where exposed underneath the manufactured home, all such ducts shall
comply with Sec. 3280.715(a)(5)(ii).
(b) Return air systems--(1) Return air openings. Provisions shall be
made to permit the return of circulating air from all rooms and living
spaces, except toilet room(s), to the circulating air supply inlet of
the furnace.
(2) Duct material. Return ducts and any diverting dampers contained
therein shall be in accordance with the following:
(i) Portions of return ducts directly above the heating surfaces, or
closer than 2 feet from the outer jacket or casing of the furnace shall
be constructed of metal in accordance with Sec. 3280.715(a)(1) or shall
be listed Class 0 or Class 1 air ducts.
(ii) Return ducts, except as required by paragraph (a) of this
section, shall be constructed of one-inch (nominal) wood boards (flame
spread classification of not more than 200), other suitable material no
more flammable than

[[Page 182]]

one-inch board or in accordance with Sec. 3280.715(a)(1).
(iii) The interior of combustible ducts shall be lined with
noncombustible material at points where there might be danger from
incandescent particles dropped through the register or furnace such as
directly under floor registers and the bottom return.
(iv) Factory made air ducts used for connecting external heating,
cooling or combination heating/cooling appliances to the supply system
and return air system of a manufactured home shall be listed by a
nationally recognized testing agency. Ducts applied to external heating
appliances or combination heating/cooling appliances supply system
outlets shall be constructed of metal in accordance with
Sec. 3280.715(a)(1) or shall be listed Class 0 or Class 1 air ducts for
those portions of the duct closer than 2 feet from the outer casing of
the appliance.
(v) Ducts applied to external appliances shall be resistant to
deteriorating environmental effects, including but not limited to
ultraviolet rays, cold weather, or moisture and shall be resistant to
insects and rodents.
(3) Sizing. The cross-sectional areas of the return air duct shall
not be less than 2 square inches for each 1,000 Btu per hour input
rating of the appliance. Dampers shall not be placed in a combination
fresh air intake and return air duct so arranged that the required
cross-sectional area will not be reduced at all possible positions of
the damper.
(4) Permanent uncloseable openings. Living areas not served by
return air ducts or closed off from the return opening of the furnace by
doors, sliding partitions, or other means shall be provided with
permanent uncloseable openings in the doors or separating partitions to
allow circulated air to return to the furnace. Such openings may be
grilled or louvered. The net free area of each opening shall be not less
than 1 square inch for every 5 square feet of total living area closed
off from the furnace by the door or partition serviced by that opening.
Undercutting doors connecting the closed-off space may be used as a
means of providing return air area. However, in the event that doors are
undercut, they shall be undercut a minimum of 2 inches and not more than
2\1/2\ inches, as measured from the top surface of the floor decking to
the bottom of the door and no more than one half of the free air area so
provided shall be counted as return air area.
(c) Joints and seams. Joints and seams of ducts shall be securely
fastened and made substantially airtight. Slip joints shall have a lap
of at least 1 inch and shall be individually fastened. Tape or caulking
compound may be used for sealing mechanically secure joints. Where used,
tape or caulking compound shall not be subject to deterioration under
long exposures to temperatures up to 200 deg. F. and to conditions of
high humidity, excessive moisture, or mildew.
(d) Supports. Ducts shall be securely supported.
(e) Registers or grilles. Fittings connecting the registers or
grilles to the duct system shall be constructed of metal or material
which complies with the requirements of Class 1 or 2 ducts under UL
181--Sixth Edition--1984, Factory Made Air Ducts and Connectors. Air
supply terminal devices (registers) when installed in kitchens,
bedrooms, and bathrooms shall be equipped with adjustable closeable
dampers. Registers or grilles shall be constructed of metal or conform
with the following:
(1) Be made of a material classified 94V-0 or 94V-1 when tested as
described in Underwriters' Laboratories, Inc., Tests for Flammability of
Plastic Materials for Parts in Devices and Appliances, UL 94-Fourth
Edition-1991.
(2) Floor registers or grilles shall resist without structural
failure a 200 lb. concentrated load on a 2-inch diameter disc applied to
the most critical area of the exposed face of the register or grille.
For this test the register or grille is to be at a temperature of not
less than 165 deg. F and is to be supported in accordance with the
manufacturer's instructions.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4589, Feb. 12, 1987; 58 FR 55019, Oct. 25, 1993]

[[Page 183]]

Subpart I--Electrical Systems

Sec. 3280.801 Scope.

(a) Subpart I of this standard and part A of Article 550 of the
National Electrical Code (NFPA No. 70-1993) cover the electrical
conductors and equipment installed within or on manufactured homes and
the conductors that connect manufactured homes to a supply of
electricity.
(b) In addition to the requirements of this standard and Article 550
of the National Electrical Code (NFPA No. 70-1993) the applicable
portions of other Articles of the National Electrical Code shall be
followed covering electrical installations in manufactured homes.
Wherever the requirements of this standard differ from the National
Electrical Code, this standard shall apply.
(c) The provisions of this standard apply to manufactured homes
intended for connection to a wiring system nominally rated 120/240
volts, 3-wire AC, with grounded neutral.
(d) All electrical materials, devices, appliances, fittings and
other equipment shall be listed or labeled by a nationally recognized
testing agency and shall be connected in an approved manner when in
service.
(e) Aluminum conductors, aluminum alloy conductors, and aluminum
core conductors such as copper clad aluminum; are not acceptable for use
in branch circuit wiring in manufactured homes.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55019, Oct. 25, 1993]

Sec. 3280.802 Definitions.

(a) The following definitions are applicable to subpart I only.
(1) Accessible (i) (As applied to equipment) means admitting close
approach because not guarded by locked doors, elevation, or other
effective means. (See readily accessible.)
(ii) (As applied to wiring methods) means capable of being removed
or exposed without damaging the manufactured home structure or finish,
or not permanently closed-in by the structure or finish of the
manufactured home (see concealed and exposed).
(2) Air conditioning or comfort cooling equipment means all of that
equipment intended or installed for the purpose of processing the
treatment of air so as to control simultaneously its temperature,
humidity, cleanliness, and distribution to meet the requirements of the
conditioned space.
(3)(i) Appliance means utilization equipment, generally other than
industrial, normally built in standardized sizes or types, which is
installed or connected as a unit to perform one or more functions, such
as clothes washing, air conditioning, food mixing, deep frying, etc.
(ii) Appliance, fixed means an appliance which is fastened or
otherwise secured at a specific location.
(iii) Appliance, portable means an appliance which is actually moved
or can easily be moved from one place to another in normal use. For the
purpose of this Standard, the following major appliances are considered
portable if cord-connected: refrigerators, clothes washers, dishwashers
without booster heaters, or other similar appliances.
(iv) Appliance, stationary means an appliance which is not easily
moved from one place to another in normal use.
(4) Attachment plug (plug cap) (cap) means a device which, by
insertion in a receptacle, establishes connection between the conductors
of the attached flexible cord and the conductors connected permanently
to the receptacle.
(5) Bonding means the permanent joining of metallic parts to form an
electrically conductive path which will assure electrical continuity and
the capacity to conduct safely any current likely to be imposed.
(6) Branch circuit (i) means the circuit conductors between the
final overcurrent device protecting the circuit and the outlet(s). A
device not approved for branch circuit protection, such as a thermal
cutout or motor overload protective device, is not considered as the
overcurrent device protecting the circuit.
(ii) Branch circuit--appliance means a branch circuit supplying
energy to one or more outlets to which appliances are to be connected,
such circuits to have no permanently connected lighting fixtures not a
part of an appliance.

[[Page 184]]

(iii) Branch circuit--general purpose means a circuit that supplies
a number of outlets for lighting and appliances.
(iv) Branch circuit--individual means a branch circuit that supplies
only one utilization equipment.
(7) Cabinet means an enclosure designed either for surface or flush
mounting, and provided with a frame, mat, or trim in which swinging
doors are hung.
(8) Circuit breaker means a device designed to open and close a
circuit by nonautomatic means, and to open the circuit automatically on
a predetermined overload of current without injury to itself when
properly applied within its rating.
(9) Concealed means rendered inaccessible by the structure or finish
of the manufactured home. Wires in concealed raceways are considered
concealed, even though they may become accessible by withdrawing them.
(See accessible (As applied to wiring methods))
(10) Connector, pressure (solderless) means a device that
establishes a connection between two or more conductors or between one
or more conductors and a terminal by means of mechanical pressure and
without the use of solder.
(11) Dead front (as applied to switches, circuit-breakers,
switchboards, and distribution panelboard) means so designed,
constructed, and installed that no current-carrying parts are normally
exposed on the front.
(12) Demand factor means the ratio of the maximum demand of a
system, or part of a system, to the total connected load of a system or
the part of the system under consideration.
(13) Device means a unit of an electrical system that is intended to
carry but not utilize electrical energy.
(14) Disconnecting means means a device, or group of devices, or
other means by which the conductors of a circuit can be disconnected
from their source of supply.
(15) Distribution panelboard means a single panel or a group of
panel units designed for assembly in the form of a single panel,
including buses, and with or without switches or automatic overcurrent
protective devices or both, for the control of light, heat, or power
circuits of small individual as well as aggregate capacity; designed to
be placed in a cabinet placed in or against a wall or partition and
accessible only from the front.
(16) Enclosed means surrounded by a case that will prevent a person
from accidentally contacting live parts.
(17) Equipment means a general term, including material, fittings,
devices, appliances, fixtures, apparatus, and the like used as a part
of, or in connection with, an electrical installation.
(18) Exposed (i) (As applied to live parts) means capable of being
inadvertently touched or approached nearer than a safe distance by a
person. It is applied to parts not suitably guarded, isolated, or
insulated. (See accessible and concealed.)
(ii) (As applied to wiring method) means on or attached to the
surface or behind panels designed to allow access. (See Accessible (as
applied to wiring methods))
(19) Externally operable means capable of being operated without
exposing the operator to contact with live parts.
(20) Feeder assembly means the overhead or under-chassis feeder
conductors, including the grounding conductor, together with the
necessary fittings and equipment, or a power supply cord approved for
manufactured home use, designed for the purpose of delivering energy
from the source of electrical supply to the distribution panelboard
within the manufactured home.
(21) Fitting means an accessory, such as a locknut, bushing, or
other part of a wiring system, that is intended primarily to perform a
mechanical rather than an electrical function.
(22) Ground means a conducting connection, whether intentional or
accidental, between an electrical circuit or equipment and earth, or to
some conducting body that serves in place of the earth.
(23) Grounded means connected to earth or to some conducting body
that serves in place of the earth.
(24) Grounded conductor means a system or circuit conductor that is
intentionally grounded.
(25) Grounding conductor means a conductor used to connect equipment
or the grounded circuit of a wiring system to a grounding electrode or
electrodes.

[[Page 185]]

(26) Guarded means covered, shielded, fenced, enclosed, or otherwise
protected by means of suitable covers, casings, barriers, rails,
screens, mats or platforms to remove the likelihood of approach or
contact by persons or objects to a point of danger.
(27) Isolated means not readily accessible to persons unless special
means for access are used.
(28) Laundry area means an area containing or designed to contain
either a laundry tray, clothes washer and/or clothes dryer.
(29) Lighting outlet means an outlet intended for the direct
connection of a lampholder, a lighting fixture, or a pendant cord
terminating in a lampholder.
(30) Manufactured home accessory building or structure means any
awning, cabana, ramada, storage cabinet, carport, fence, windbreak or
porch established for the use of the occupant of the manufactured home
upon a manufactured home lot.
(31) Manufactured home service equipment means the equipment
containing the disconnecting means, overcurrent protective devices, and
receptacles or other means for connecting a manufactured home feeder
assembly.
(32) Outlet means a point on the wiring system at which current is
taken to supply utilization equipment.
(33) Panelboard means a single panel or group of panel units
designed for assembly in the form of a single panel; including buses,
automatic overcurrent protective devices, and with or without switches
for the control of light, heat, or power circuits; designed to be placed
in a cabinet or cutout box placed in or against a wall or partition and
accessible only from the front.
(34) Raceway means any channel for holding wires, cables, or busbars
that is designed expressly for, and used solely for, this purpose.
Raceways may be of metal or insulating material, and the term includes
rigid metal conduit, rigid nonmetallic conduit, flexible metal conduit,
electrical metallic tubing, underfloor raceways, cellular concrete floor
raceways, cellular metal floor raceways, surface raceways, structural
raceways, wireways, and busways.
(35) Raintight means so constructed or protected that exposure to a
beating rain will not result in the entrance of water.
(36) Readily accessible means capable of being reached quickly for
operation, renewal, or inspection, without requiring those to whom ready
access is requisite to climb over or remove obstacles or to resort to
portable ladders, chairs, etc. (See Accessible.)
(37) Receptacle means a contact device installed at an outlet for
the connection of a single attachment plug. A single receptacle is a
single contact device with no other contact device on the same yoke. A
multiple receptacle is a single device containing two or more
receptacles.
(38) Receptacle outlet means an outlet where one or more receptacles
are installed.
(39) Utilization equipment means equipment which utilizes electric
energy for mechanical, chemical, heating, lighting, or similar purposes.
(40) Voltage (of a circuit) means the greatest root-mean-square
(effective) difference of potential between any two conductors of the
circuit concerned. Some systems, such as 3-phase 4-wire, single-phase 3-
wire, and 3-wire direct-current may have various circuits of various
voltages.
(41) Weatherproof means so constructed or protected that exposure to
the weather will not interfere with successful operation. Rainproof,
raintight, or watertight equipment can fulfill the requirements for
weatherproof where varying weather conditions other than wetness, such
as snow, ice, dust, or temperature extremes, are not a factor.

Sec. 3280.803 Power supply.

(a) The power supply to the manufactured home shall be a feeder
assembly consisting of not more than one listed 50 ampere manufactured
home power-supply cords, or a permanently installed circuit. A
manufactured home that is factory-equipped with gas or oil-fired central
heating equipment and cooking appliances shall be permitted to be
provided with a listed manufactured home power-supply cord rated 40
amperes.

[[Page 186]]

(b) If the manufactured home has a power-supply cord, it shall be
permanently attached to the distribution panelboard or to a junction box
permanently connected to the distribution panelboard, with the free end
terminating in an attachment plug cap.
(c) Cords with adapters and pigtail ends, extension cords, and
similar items shall not be attached to, or shipped with, a manufactured
home.
(d) A listed clamp or the equivalent shall be provided at the
distribution panelboard knockout to afford strain relief for the cord to
prevent strain from being transmitted to the terminals when the power-
supply cord is handled in its intended manner.
(e) The cord shall be of an approved type with four conductors, one
of which shall be identified by a continuous green color or a continuous
green color with one or more yellow stripes for use as the grounding
conductor.
(f) The attachment plug cap shall be a 3-pole, 4-wire grounding
type, rated 50 amperes, 125/250 volts with a configuration as shown
herein and intended for use with the 50-ampere, 125/250 receptacle
configuration shown. It shall be molded of butyl rubber, neoprene, or
other approved materials which have been found suitable for the purpose,
and shall be molded to the flexible cord so that it adheres tightly to
the cord at the point where the cord enters the attachment-plug cap. If
a right-angle cap is used, the configuration shall be so oriented that
the grounding member is farthest from the cord.
(g) The overall length of a power-supply cord, measured from the end
of the cord, including bared leads, to the face of the attachment-plug
cap shall not be less than 21 feet and shall not exceed 36\1/2\ feet.
The length of cord from the face of the attachment-plug cap to the point
where the cord enters the manufactured home shall not be less than 20
feet.
[GRAPHIC] [TIFF OMITTED] TC17OC91.007

50-ampere 125/250 volt receptacle and attachment-plug-cap
configurations, 3 pole, 4-wire grounding types used for manufactured
home supply cords and manufactured home parks. Complete details of the
50-ampere cap and receptacle can be found in the American National
Standard Dimensions of Caps, Plugs and Receptacles, Grounding Type (ANSI
C73.17--1972).

(h) The power supply cord shall bear the following marking: ``For
use with manufactured homes--40 amperes'' or ``For use with manufactured
homes--50 amperes.''
(i) Where the cord passes through walls or floors, it shall be
protected by means of conduit and bushings or equivalent. The cord may
be installed within the manufactured home walls, provided a continuous
raceway is installed from the branch-circuit panelboard to the underside
of the manufactured home floor. The raceway may be rigid conduit,
electrical metallic tubing or polyethylene (PE), poly-vinylchloride
(PVC) or acrylonitrile-butadiene-styrene (ABS) plastic tubing having a
minimum wall thickness of nominal \1/8\ inch.
(j) Permanent provisions shall be made for the protection of the
attachment-plug cap of the power supply cord and any connector cord
assembly or receptacle against corrosion and mechanical damage if such
devices are in an exterior location while the manufactured home is in
transit.
(k) Where the calculated load exceeds 50 amperes or where a
permanent feeder is used, the supply shall be by means of:
(1) One mast weatherhead installation installed in accordance with
Article 230 of the National Electrical Code NFPA No. 70-1993 containing
four continuous insulated, color-coded, feeder conductors, one of which
shall be an equipment grounding conductor; or
(2) An approved raceway from the disconnecting means in the
manufactured home to the underside of the manufactured home with
provisions for the attachment of a suitable junction box or fitting to
the raceway on the underside of the manufactured home. The manufacturer
shall provide in his written installation instructions, the proper
feeder conductor sizes for the raceway and the size of the junction box
to be used; or
(3) Service equipment installed on the manufactured home in
accordance

[[Page 187]]

with Article 230 of the National Electrical Code NFPA No. 70-1993; and
(i) The installation shall be completed by the manufacturer except
for the service connections, the meter and the grounding electrode
conductor;
(ii) Exterior equipment, or the enclosure in which it is installed
shall be weatherproof and installed in accordance with Article 373-2 of
the National Electrical Code NFPA No. 70-1993. Conductors shall be
suitable for use in wet locations;
(iii) The neutral conductor shall be connected to the system
grounding conductor on the supply side of the main disconnect in
accordance with Articles 250-23, 25, and 53 of NFPA No. 70-1993.
(iv) The manufacturer shall include in its written installation
instructions one method of grounding the service equipment at the
installation site;
(v) The minimum size grounding electrode conductor shall be
specified in the instructions; and
(vi) A red ``Warning'' label shall be mounted on or adjacent to the
service equipment. The label shall state:

``Warning--do not provide electrical power until the grounding
electrode is installed and connected (see installation instructions).''

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 4589, Feb. 12, 1987; 58 FR 55019, Oct. 25, 1993]

Sec. 3280.804 Disconnecting means and branch-circuit protective equipment.

(a) The branch-circuit equipment shall be permitted to be combined
with the disconnecting means as a single assembly. Such a combination
shall be permitted to be designated as a distribution panelboard. If a
fused distribution panelboard is used, the maximum fuse size of the
mains shall be plainly marked with lettering at least \1/4\-inch high
and visible when fuses are changed. See section 110-22 of the National
Electrical Code (NFPA No. 70-1993) concerning identification of each
disconnecting means and each service, feeder, or branch circuit at the
point where it originated and the type marking needed.
(b) Plug fuses and fuseholders shall be tamper-resistant, Type
``S,'' enclosed in dead-front fuse panelboards. Electrical distribution
panels containing circuit breakers shall also be dead-front type.
(c) Disconnecting means. A single disconnecting means shall be
provided in each manufactured home consisting of a circuit breaker, or a
switch and fuses and their accessories installed in a readily accessible
location near the point of entrance of the supply cord or conductors
into the manufactured home. The main circuit breakers or fuses shall be
plainly marked ``Main.'' This equipment shall contain a solderless type
of grounding connector or bar for the purposes of grounding with
sufficient terminals for all grounding conductors. The neutral bar
termination of the grounded circuit conductors shall be insulated.
(d) The disconnecting equipment shall have a rating suitable for the
connected load. The distribution equipment, either circuit breaker or
fused type, shall be located a minimum of 24 inches from the bottom of
such equipment to the floor level of the manufactured home.
(e) A distribution panelboard employing a main circuit breaker shall
be rated 50 amperes and employ a 2-pole circuit breaker rated 40 amperes
for a 40-ampere supply cord, or 50 amperes for a 50-ampere supply cord.
A distribution panelboard employing a disconnect switch and fuses shall
be rated 60 amperes and shall employ a single 2-pole, 60-ampere
fuseholder with 40- or 50-ampere main fuses for 40- or 50-ampere supply
cords, respectively. The outside of the distribution panelboard shall be
plainly marked with the fuse size.
(f) The distribution panelboard shall not be located in a bathroom,
or in any other inaccessible location, but shall be permitted just
inside a closet entry if the location is such that a clear space of 6
inches to easily ignitable materials is maintained in front of the
distribution panelboard, and the distribution panelboard door can be
extended to its full open position (at least 90 degrees). A clear
working space at least 30 inches wide and 30 inches in front of the
distribution panelboard shall be provided. This space shall extend from
floor to the top of the distribution panelboard.

[[Page 188]]

(g) Branch-circuit distribution equipment shall be installed in each
manufactured home and shall include overcurrent protection for each
branch circuit consisting of either circuit breakers or fuses.
(1) The branch circuit overcurrent devices shall be rated:
(i) Not more than the circuit conductors; and
(ii) Not more than 150 percent of the rating of a single appliance
rated 13.3 amperes or more which is supplied by an individual branch
circuit; but
(iii) Not more than the fuse size marked on the air conditioner or
other motor-operated appliance.
(h) A 15-ampere multiple receptacle shall be acceptable when
connected to a 20-ampere laundry circuit.
(i) When circuit breakers are provided for branch-circuit protection
240 circuits shall be protected by 2-pole common or companion trip, or
handle-tied paired circuit breakers.
(j) A 3 inch by 1-3/4 inch minimum size tag made of etched, metal-
stamped or embossed brass, stainless steel, anodized or alclad aluminum
not less than 0.020 inch thick, or other approval material (e.g., 0.005
inch plastic laminates) shall be permanently affixed on the outside
adjacent to the feeder assembly entrance and shall read: This connection
for 120/240 Volt, 3-Pole, 4-Wire, 60 Hertz, ________ Ampere Supply. The
correct ampere rating shall be marked on the blank space.
(k) When a home is provided with installed service equipment, a
single disconnecting means for disconnecting the branch circuit
conductors from the service entrance conductors shall be provided in
accordance with Part F of Article 230 of the National Electrical Code,
NFPA No. 70-1993. The disconnecting means shall be listed for use as
service equipment. The disconnecting means may be combined with the
disconnect required by Sec. 3280.804(c). The disconnecting means shall
be rated not more than the ampere supply or service capacity indicated
on the tag required by paragraph (l) of this section.
(l) When a home is provided with installed service equipment, the
electrical nameplate required by Sec. 3280.804(j) shall read: ``This
connection for 120/240 volt, 3 pole, 3 wire, 60 Hertz, ________ Ampere
Supply.'' The correct ampere rating shall be marked in the blank space.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 961, Jan. 4, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 52 FR 4589,
Feb. 12, 1987; 58 FR 55019, Oct. 25, 1993]

Sec. 3280.805 Branch circuits required.

(a) The number of branch circuits required shall be determined in
accordance with the following:
(1) Lighting, based on 3 volt-amperes per square foot times outside
dimensions of the manufactured home (coupler excluded) divided by 120
volts times amperes to determine number of 15 or 20 ampere lighting area
circuits. e.g. [3 x length x width--[120 x (15 or 20)] = number of
15 or 20 ampere circuits.
(2) Small appliances. For the small appliance load in kitchen,
pantry dining room and breakfast rooms of manufactured homes, two or
more 20-ampere appliance branch circuits, in addition to the branch
circuit specified in Sec. 3280.805(a)(1), shall be provided for all
receptacle outlets in these rooms, and such circuits shall have no other
outlets. Receptacle outlets supplied by at least two appliance
receptacle branch circuits shall be installed in the kitchen.
(3) General appliances (Including furnace, water heater, range, and
central or room air conditioner, etc.). There shall be one or more
circuits of adequate rating in accordance with the following:
(i) Ampere rating of fixed appliances not over 50 percent of circuit
rating if lighting outlets (receptacles, other than kitchen, dining
area, and laundry, considered as lighting outlets) are on same circuit;
(ii) For fixed appliances on a circuit without lighting outlets, the
sum of rated amperes shall not exceed the branch-circuit rating. Motor
loads or other continuous duty loads shall not exceed 80 percent of the
branch circuit rating.
(iii) The rating of a single cord and plug connected appliances on a
circuit having no other outlets, shall not exceed 80 percent of the
circuit rating.
(iv) The rating of range branch circuit shall be based on the range
demand as specified or ranges in

[[Page 189]]

Sec. 3280.811, Item B(5) of Method 1. For central air conditioning, see
Article 440 of the National Electrical Code (NFPA No. 70-1993).
(v) Where a laundry area is provided, a 20 ampere branch circuit
shall be provided to supply laundry receptacle outlets. This circuit
shall have no other outlets. See Sec. 3280.806(a)(7).
(b) [Reserved]

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55020, Oct. 25, 1993]

Sec. 3280.806 Receptacle outlets.

(a) All receptacle outlets shall be:
(1) Of grounding type;
(2) Installed according to section 210-7 of the National Electrical
Code (NFPA No. 70-1993).
(3) Except when supplying specific appliances, be parallel-blade,
15-ampere, 125-volt, either single or duplex.
(b) All 120 volt single phase, 15 and 20 ampere receptacle outlets,
including receptacles in light fixtures, installed outdoors, in
compartments accessible from the outdoors, in bathrooms, and within 6
feet of a kitchen sink to serve counter top surfaces shall have ground-
fault circuit protection for personnel. Feeders supplying branch
circuits may be protected by a ground-fault circuit-interrupter in lieu
of the provision for such interrupters specified above. Receptacles
dedicated for washer and dryers, also located in a bathroom, are exempt
from this requirement.
(c) There shall be an outlet of the grounding type for each cord-
connected fixed appliance installed.
(d) Receptacle outlets required. Except in the bath and hall areas,
receptacle outlets shall be installed at wall spaces 2 feet wide or
more, so that no point along the floor line is more than 6 feet,
measured horizontally, from an outlet in that space. In addition, a
receptacle outlet shall be installed:
(1) Over or adjacent to counter tops in the kitchen (at least one on
each side of the sink if counter tops are on each side and 12 inches or
over in width).
(2) Adjacent to the refrigerator and free-standing gas-range space.
A duplex receptacle may serve as the outlet for a countertop and a
refrigerator.
(3) At counter top spaces for built-in vanities.
(4) At counter top spaces under wall-mounted cabinets.
(5) In the wall, at the nearest point where a bar type counter
attaches to the wall.
(6) In the wall at the nearest point where a fixed room divider
attaches to the wall.
(7) In laundry areas within 6 feet of the intended location of the
appliance(s).
(8) At least one receptacle outlet shall be installed outdoors.
(9) Adjacent to bathroom basins or integral with the light fixture
over the bathroom basin.
(10) Receptacle outlets are not required in the following locations:
(i) Wall space occupied by built-in kitchen or wardrobe cabinets,
(ii) Wall space behind doors which may be opened fully against a
wall surface,
(iii) Room dividers of the lattice type, less than 8 feet long, not
solid within 6 inches of the floor,
(iv) Wall space afforded by bar type counters.
(e) Receptacle outlets shall not be installed in or within reach (30
inches) of a shower or bathtub space.
(f) Receptacle outlets shall not be installed above electric
baseboard heaters.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55020, Oct. 25, 1993]

Sec. 3280.807 Fixtures and appliances.

(a) Electrical materials, devices, appliances, fittings, and other
equipment installed, intended for use in, or attached to the
manufactured home shall be approved for the application and shall be
connected in an approved manner when in service. Facilities shall be
provided to securely fasten appliances when the manufactured home is in
transit. (See Sec. 3280.809.)
(b) Specifically listed pendant-type fixtures or pendant cords shall
be permitted in manufactured homes.
(c) If a lighting fixture is provided over a bathtub or in a shower
stall, it shall be of the enclosed and gasketed type, listed for wet
locations. See also

[[Page 190]]

Article 410-4(d) of the National Electrical Code NFPA No. 70-1993.
(d) The switch for shower lighting fixtures and exhaust fans located
over a tub or in a shower stall shall be located outside the tub shower
space. (See Sec. 3280.806(e).)
(e) Any combustible wall or ceiling finish exposed between the edge
of a fixture canopy, or pan and an outlet box shall be covered with non-
combustible or limited combustible material.
(f) Every appliance shall be accessible for inspection, service,
repair, or replacement without removal of permanent construction.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 52 FR 35543, Sept. 22, 1987; 58 FR 55020, Oct. 25, 1993]

Sec. 3280.808 Wiring methods and materials.

(a) Except as specifically limited in this part, the wiring methods
and materials specified in the National Electrical Code (NFPA No. 70-
1993) shall be used in manufactured homes.
(b) Nonmetallic outlet boxes shall be acceptable only with
nonmetallic cable.
(c) Nonmetallic cable located 15 inches or less above the floor, if
exposed, shall be protected from physical damage by covering boards,
guard strips, or conduit. Cable likely to be damaged by stowage shall be
so protected in all cases.
(d) Nonmetallic sheathed cable shall be secured by staples, straps,
or similar fittings so designed and installed as not to injure any
cable. Cable shall be secured in place at intervals not exceeding 4\1/2\
feet and within 12 inches from every cabinet, box or fitting.
(e) Metal-clad and nonmetallic cables shall be permitted to pass
through the centers of the wide side of 2-inch by 4-inch studs. However,
they shall be protected where they pass through 2-inch by 2-inch studs
or at other studs or frames where the cable or armor would be less than
1\1/2\ inches from the inside or outside surface of the studs when the
wall covering materials are in contact with the studs. Steel plates on
each side of the cable, or a tube, with not less than No. 16 MSG wall
thickness shall be required to protect the cable. These plates or tubes
shall be securely held in place.
(f) Where metallic faceplates are used they shall be effectively
grounded.
(g) If the range, clothes dryer, or similar appliance is connected
by metalclad cable or flexible conduit, a length of not less than three
feet of free cable or conduit shall be provided to permit moving the
appliance. Type NM or Type SE cable shall not be used to connect a range
or a dryer. This shall not prohibit the use of Type NM or Type SE cable
between the branch circuit overcurrent protective device and a junction
box or range or dryer receptacle.
(h) Threaded rigid metal conduit shall be provided with a locknut
inside and outside the box, and a conduit bushing shall be used on the
inside. Rigid nonmetallic conduit shall be permitted. Inside ends of the
conduit shall be reamed.
(i) Switches shall be rated as follows:
(1) For lighting circuits, switches, shall have a 10-ampere, 120-125
volt rating; or higher if needed for the connected load.
(2) For motors or other loads, switches shall have ampere or
horsepower ratings, or both, adequate for loads controlled. (An ``AC
general-use'' snap switch shall be permitted to control a motor 2
horsepower or less with full-load current not over 80 percent of the
switch ampere rating).
(j) At least 4 inches of free conductor shall be left at each outlet
box except where conductors are intended to loop without joints.
(k) When outdoor or under-chassis line-voltage wiring is exposed to
moisture or physical damage, it shall be protected by rigid metal
conduit. The conductors shall be suitable for wet locations. Electrical
metallic tubing may be used when closely routed against frames, and
equipment enclosures.
(l) The cables or conductors shall be Type NMC, TW, or equivalent.
(m) Outlet boxes of dimensions less than those required in table
370-6(a) of the National Electrical Code (NFPA No. 70-1993) shall be
permitted provided the box has been tested and approved for the purpose.
(n) Boxes, fittings, and cabinets shall be securely fastened in
place, and shall

[[Page 191]]

be supported from a structural member of the home, either directly or by
using a substantial brace. Snap-in type boxes provided with special wall
or ceiling brackets that securely fasten boxes in walls or ceilings
shall be permitted.
(o) Outlet boxes shall fit closely to openings in combustible walls
and ceilings, and they shall be flush with such surfaces.
(p) Appliances having branch-circuit terminal connections which
operate at temperatures higher than 60 deg. C (140 deg. F) shall have
circuit conductors as described in paragraphs (p) (1) and (2) of this
section:
(1) Branch-circuit conductors having an insulation suitable for the
temperature encountered shall be permitted to run directly to the
appliance.
(2) Conductors having an insulation suitable for the temperature
encountered shall be run from the appliance terminal connections to a
readily accessible outlet box placed at least one foot from the
appliance. These conductors shall be in a suitable raceway which shall
extend for at least 4 feet.
(q) A substantial brace for securing a box, fitting or cabinet shall
be as described in the National Electrical Code, NFPA 70-1993 Article
370-13(d), or the brace, including the fastening mechanism to attach the
brace to the home structure, shall withstand a force of 50 lbs. applied
to the brace at the intended point(s) of attachment for the box in a
direction perpendicular to the surface in which the box is installed.
(r) Outlet boxes shall fit closely to the openings in combustible
wall and ceilings with a maximum of a \1/8\ inch gap. They shall be
flush with the finish surface or project therefrom.
(s) Where the sheathing of NM cable has been cut or damaged and
visual inspection reveals that the conductor and its insulation has not
been damaged, it shall be permitted to repair the cable sheath with
electrical tape which provides equivalent protection to the sheath.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55020, Oct. 25, 1993]

Sec. 3280.809 Grounding.

(a) General. Grounding of both electrical and nonelectrical metal
parts in a manufactured home shall be through connection to a grounding
bus in the manufactured home distribution panelboard. The grounding bus
shall be grounded through the green-colored conductor in the supply cord
or the feeder wiring to the service ground in the service-entrance
equipment located adjacent to the manufactured home location. Neither
the frame of the manufactured home nor the frame of any appliance shall
be connected to the neutral conductor in the manufactured home.
(b) Insulated neutral. (1) The grounded circuit conductor (neutral)
shall be insulated from the grounding conductors and from equipment
enclosures and other grounded parts. The grounded (neutral) circuit
terminals in the distribution panelboard and in ranges, clothes dryers,
counter-mounted cooking units, and wall-mounted ovens shall be insulated
from the equipment enclosure. Bonding screws, straps, or buses in the
distribution panelboard or in appliances shall be removed and discarded.
However, when service equipment is installed on the manufactured home,
the neutral and the ground bus may be connected in the distribution
panel.
(2) Connection of ranges and clothes dryers with 120/240 volt, 3-
wire ratings shall be made with 4 conductor cord and 3 pole, 4-wire
grounding type plugs, or by type AC metal clad conductors enclosed in
flexible metal conduit. For 120 volt rated devices a 3-conductor cord
and a 2-pole, 3-wire grounding type plug shall be permitted.
(c) Equipment grounding means. (1) The green-colored grounding wire
in the supply cord or permanent feeder wiring shall be connected to the
grounding bus in the distribution panelboard or disconnecting means.
(2) In the electrical system, all exposed metal parts, enclosures,
frames, lamp fixture canopies, etc., shall be effectively bonded to the
grounding terminal or enclosure of the distribution panelboard.
(3) Cord-connected appliances, such as washing machines, clothes
dryers, refrigerators, and the electrical system of gas ranges, etc.,
shall be grounded by means of an approved cord with

[[Page 192]]

grounding conductor and grounding-type attachment plug.
(d) Bonding of noncurrent-carrying metal parts. (1) All exposed
noncurrent-carrying metal parts that may become energized shall be
effectively bonded to the grounding terminal or enclosure of the
distribution panelboard. A bonding conductor shall be connected between
each distribution panelboard and an accessible terminal on the chassis.
(2) Grounding terminals shall be of the solderless type and approved
as pressure-terminal connectors recognized for the wire size used. Star
washers or other approved paint-penetrating fitting shall be used to
bond terminals to chassis or other coated areas. The bonding conductor
shall be solid or stranded, insulated or bare and shall be No. 8 copper
minimum, or equal. The bonding conductor shall be routed so as not to be
exposed to physical damage. Protection can be afforded by the
configuration of the chassis.
(3) Metallic gas, water and waste pipes and metallic air-circulating
ducts shall be considered bonded if they are connected to the terminal
on the chassis (see Sec. 3280.809) by clamps, solderless connectors, or
by suitable grounding-type straps.
(4) Any metallic roof and exterior covering shall be considered
bonded if (i) the metal panels overlap one another and are securely
attached to the wood or metal frame parts by metallic fasteners, and
(ii) if the lower panel of the metallic exterior covering is secured by
metallic fasteners at a cross member of the chassis by two metal straps
per manufactured home unit or section at opposite ends. The bonding
strap material shall be a minimum of 4 inches in width of material
equivalent to the skin or a material of equal or better electrical
conductivity. The straps shall be fastened with paint-penetrating
fittings (such as screws and star washers or equivalent).

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55020, Oct. 25, 1993]

Sec. 3280.810 Electrical testing.

(a) Dielectric strength test. The wiring of each manufactured home
shall be subjected to a 1-minute, 900 to 1079 volt dielectric strength
test (with all switches closed) between live parts and the manufactured
home ground, and neutral and the manufactured home ground.
Alternatively, the test may be performed at 1080 to 1250 volts for 1
second. This test shall be performed after branch circuits are complete
and after fixtures or appliances are installed. Fixtures or appliances
which are listed shall not be required to withstand the dielectric
strength test.
(b) Each manufactured home shall be subject to:
(1) A continuity test to assure that metallic parts are properly
bonded;
(2) Operational test to demonstrate that all equipment, except water
heaters, electric furnaces, dishwashers, clothes washers/dryers, and
portable appliances, is connected and in working order; and
(3) Polarity checks to determine that connections have been properly
made. Visual verification shall be an acceptable check.

[58 FR 55020, Oct. 25, 1993]

Sec. 3280.811 Calculations.

(a) The following method shall be employed in computing the supply
cord and distribution-panelboard load for each feeder assembly for each
manufactured home and shall be based on a 3-wire, 120/240 volt supply
with 120 volt loads balanced between the two legs of the 3-wire system.
The total load for determining power supply by this method is the
summation of:
(1) Lighting and small appliance load as calculated below:
(i) Lighting volt-amperes: Length time width of manufactured home
(outside dimensions exclusive of coupler) times 3 volt-amperes per
square foot; e.g. Length x width x 3=lighting volt-amperes.
(ii) Small appliance volt-amperes: Number of circuits time 1,500
volt-amperes for each 20-ampere appliance receptacle circuit (see
definition of ``Appliance Portable'' with Note): e.g. Number of circuits
x 1,500=small appliance volt-amperes.
(iii) Total volts-amperes: Lighting volts-amperes plus small
appliance=total volt-amperes.
(iv) First 3,000 total volts-amperes at 100 percent plus remainder
at 35 percent=watts to be divided by 240

[[Page 193]]

volts to obtain current (amperes) per leg.
(2) Nameplate amperes for motors and heater loads (exhaust fans, air
conditioners, electric, gas, or oil heating). Omit smaller of air
conditioning and heating except include blower motor if used as air
conditioner evaporator motor. When an air conditioner is not installed
and a 40-ampere power supply cord is provided, allow 15 amperes per leg
for air conditioning.
(3) 25 percent of current of largest motor in paragraph (a)(2) of
this section.
(4) Total of nameplate amperes for: Disposal, dishwasher, water
heater, clothes dryer, wall-mounted oven, cooking units. Where number of
these appliances exceeds three, use 75 percent of total.
(5) Derive amperes for free-standing range (as distinguished from
separate ovens and cooking units) by dividing values below by 240 volts.

------------------------------------------------------------------------
Nameplate rating (in watts) Use (in watts)
------------------------------------------------------------------------
10,000 or less............................ 80 percent of rating.
10,001 to 12,500.......................... 8,000.
12,501 to 13,500.......................... 8,400.
13,501 to 14,500.......................... 8,800.
14,501 to 15,500.......................... 9,200.
15,501 to 16,500.......................... 9,600.
16,501 to 17,500.......................... 10,000.
------------------------------------------------------------------------

(6) If outlets or circuits are provided for other than factory-
installed appliances, include the anticipated load. The following
example is given to illustrate the application of this Method of
Calculation:

Example A manufactured home is 70 x 10 feet and has two portable
appliance circuits, a 1000 volt-ampere 240 volt heater, a 200 volt-
ampere 120 volt exhaust fan, a 400 volts-ampere 120 volt dishwasher and
a 7000 volt-ampere electric range.

------------------------------------------------------------------------
Volt-
Lighting and small appliance load ampheres
------------------------------------------------------------------------
Lighting 70 x 10 x 3.......................................... 2,100
Small Appliance............................................... 3,000
---------
Total................................................... 5,100
1st. 3,000 Volt-Ampheres at 100%.............................. 3,000
Remainder (5,100 -3,000 =2,100, at 35%........................ 735
---------
Total................................................... 3,735
------------------------------------------------------------------------

------------------------------------------------------------------------
Amperes Amperes
per leg A per leg B
------------------------------------------------------------------------
Lighting and small Appliance...................... 15.5 15.5
Heater 240 volt................................... 4.1 4.1
Fan 120 volt...................................... 1.7 .........
Dishwasher 120 volt............................... ......... 3.3
Range............................................. 23.3 23.3
---------------------
Total....................................... 44.6 46.2
------------------------------------------------------------------------
Note: Based on the higher current calculated for either leg, use one 50-
A supply cord.

(b) The following is an optional method of calculation for lighting
and appliance loads for manufactured homes served by single 3-wire 120/
240 volt set of feeder conductors with an ampacity of 100 or greater.
The total load for determining the feeder ampacity may be computed in
accordance with the following table instead of the method previously
specified. Feeder conductors whose demand load is determined by this
optional calculation shall be permitted to have the neutral load
determined by section 220-22 of the National Electrical Code (NFPA No.
70-1993). The loads identified in the table as ``other load'' and as
``Remainder of other load'' shall include the following:
(1) 1500 volt-amperes for each 2-wire, 20-ampere small appliance
branch circuit and each laundry branch circuit specified.
(2) 3 volt-amperes per square foot for general lighting and general-
use receptacles.
(3) The nameplate rating of all fixed appliances, ranges, wall-
mounted ovens, counter-mounted cooking units, and including 4 or more
separately controlled space heating loads.
(4) The nameplate ampere or kVA rating of all motors and of all low-
power-factor loads.
(5) The largest of the following:
(i) Air conditioning load;
(ii) The 65 percent diversified demand of the central electric space
heating load;
(iii) The 65 percent diversified demand of the load of less than
four separately-controlled electric space heating units.
(iv) The connected load of four or more separately-controlled
electric space heating units.

[[Page 194]]

Optional Calculation for Manufactured Homes With 110-Ampere or Larger
Service
------------------------------------------------------------------------
Demand
Load (in kilowatt or kilovoltampere) factor
(percent)
------------------------------------------------------------------------
Air-conditioning and cooling including heat pump compressors 100
Central electric space heating.............................. 65
Less than 4 separately controlled electric space heating 65
units......................................................
1st 10 kW of all other load................................. 100
Remainder of other load..................................... 40
------------------------------------------------------------------------

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55021, Oct. 25, 1993]

Sec. 3280.812 Wiring of expandable units and dual units.

(a) Expandable or multiple unit manufactured homes shall use fixed-
type wiring methods and materials for connecting such units to each
other.
(b) Expandable or multiple unit manufactured homes not having
permanently installed feeders and which are to be moved from one
location to another, shall be permitted to have disconnecting means with
branch circuit protective equipment in each unit when so located that
after assembly or joining together of units the requirements of
Sec. 3280.803 will be met.

Sec. 3280.813 Outdoor outlets, fixtures, air-conditioning equipment, etc.

(a) Outdoor fixtures and equipment shall be listed for use in wet
locations, except that if located on the underside of the home or
located under roof extensions or similarly protected locations, they may
be listed for use in damp locations.
(b) A manufactured home provided with an outlet designed to energize
heating and/or air conditioning equipment located outside the
manufactured home, shall have permanently affixed, adjacent to the
outlet, a metal tag which reads:

This Connection Is for Air Conditioning Equipment Rated at Not More
Than ------ Amperes, at ------ Volts, 60 Hertz. A disconnect shall be
located within sight of the appliance.

The correct voltage and ampere ratings shall be given. The tag shall not
be less than 0.020 inch, etched Brass, stainless steel, anodized or
alclad aluminum or equivalent or other approved material (e.g., .005
inch plastic laminates). The tag shall be not less than 3 inches by 1\3/
4\ inches minimum size.

[40 FR 58752, Dec. 18, 1975, as amended at 42 FR 961, Jan. 4, 1977.
Redesignated at 44 FR 20679, Apr. 6, 1979, as amended at 58 FR 55021,
Oct. 25, 1993]

Sec. 3280.814 Painting of wiring.

During painting or staining of the manufactured home, it shall be
permitted to paint metal raceways (except where grounding continuity
would be reduced) or the sheath of the nonmetallic cable. Some
arrangement, however, shall be made so that no paint shall be applied to
the individual wires, as the color coding may be obliterated by the
paint.

Sec. 3280.815 Polarization.

(a) The identified (white) conductor shall be employed for grounding
circuit conductors only and shall be connected to the identified (white)
terminal or lead on receptacle outlets and fixtures. It shall be the
unswitched wire in switched circuits, except that a cable containing an
identified conductor (white) shall be permitted for single-pole three-
way or four-way switch loops where the connections are made so that the
unidentified conductor is the return conductor from the switch to the
outlet. Painting of the terminal end of the wire shall not be required.
(b) If the identified (white) conductor of a cable is used for other
than grounded conductors or for other than switch loops as explained
above (for a 240 volt circuit for example), the conductor shall be
finished in a color other than white at each outlet where the conductors
are visible and accessible.
(c) Green-colored wires or green with yellow stripe shall be used
for grounding conductors only.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 58 FR 55021, Oct. 25, 1993]

Sec. 3280.816 Examination of equipment for safety.

The examination or inspection of equipment for safety, according to
this standard, shall be conducted under uniform conditions and by
organizations

[[Page 195]]

properly equipped and qualified for experimental testing, inspections of
the run of goods at factories, and service-value determinations through
field examinations.

Subpart J--Transportation

Sec. 3280.901 Scope.

Subpart J of this standard covers the general requirement for
designing the structure of the manufactured home to fully withstand the
adverse effects of transportation shock and vibration without
degradation of the integrated structure or of its component parts and
the specific requirements pertaining to the transportation system and
its relationship to the structure.

Sec. 3280.902 Definitions.

(a) Chassis means the entire transportation system comprising the
following subsystems: drawbar and coupling mechanism, frame, running
gear assembly, and lights.
(b) Drawbar and coupling mechanism means the rigid assembly,
(usually an A frame) upon which is mounted a coupling mechanism, which
connects the manufactured home's frame to the towing vehicle.
(c) Frame means the fabricated rigid substructure which provides
considerable support to the affixed manufactured home structure both
during transport and on-site; and also provides a platform for
securement of the running gear assembly, the drawbar and coupling
mechanism.
(d) Running gear assembly means the subsystem consisting of
suspension springs, axles, bearings, wheels, hubs, tires, and brakes,
with their related hardware.
(e) Lights means those safety lights and associated wiring required
by applicable U.S. Department of Transportation regulations.
(f) Transportation system, (Same as chassis, above).
(g) Highway, includes all roads and streets to be legally used in
transporting the manufactured home.

[40 FR 58752, Dec. 18, 1975. Redesignated at 44 FR 20679, Apr. 6, 1979,
as amended at 47 FR 28093, June 29, 1982]

Sec. 3280.903 General requirements for designing the structure to withstand transportation shock and vibration.

(a) The cumulative effect of highway transportation shock and
vibration upon a manufactured home structure may result in incremental
degradation of its designed performance in terms of providing a safe,
healthy and durable dwelling. Therefore, the manufactured home shall be
designed, in terms of its structural, plumbing, mechanical and
electrical systems, to fully withstand such transportation forces during
its intended life. (See Secs. 3280.303(c) and 3280.305(a)).
(b) Particular attention shall be given to maintaining watertight
integrity and conserving energy by assuring that structural components
in the roof and walls (and their interfaces with vents, windows, doors,
etc.) are capable of resisting highway shock and vibration forces during
primary and subsequent secondary transportation moves.
(c) In place of an engineering analysis, either of the following may
be accepted:
(1) Documented technical data of suitable highway tests which were
conducted to simulate transportation loads and conditions; or
(2) Acceptable documented evidence of actual transportation
experience which meets the intent of this subpart.

Sec. 3280.904 Specific requirements for designing the transportation system.

(a) General. The entire system (frame, drawbar and coupling
mechanism, running gear assembly, and lights) shall be designed and
constructed as an integrated, balanced and durable unit which is safe
and suitable for its specified use during the intended life of the
manufactured home. In operation, the transportation system (supporting
the manufactured home structure and its contents) shall effectively
respond to the control of the braking, while traveling at applicable
towing vehicle in terms of tracking and highway speeds and in normal
highway traffic conditions.
Note: While the majority of manufactured homes utilize a fabricated
steel frame assembly, upon which the manufactured home structure is
constructed, it is not the intent

[[Page 196]]

of this standard to limit innovation. Therefore, other concepts, such as
integrating the frame function into the manufactured home structure, are
acceptable provided that such design meets the intent and requirements
of this part).
(b) Specific requirements--(1) Drawbar. The drawbar shall be
constructed of sufficient strength, rigidity and durability to safely
withstand those dynamic forces experienced during highway
transportation. It shall be securely fastened to the manufactured home
frame by either a continuous weld or by bolting.
(2) Coupling mechanism. The coupling mechanism (which is usually of
the socket type) shall be securely fastened to the drawbar in such a
manner as to assure safe and effective transfer of the maximum loads,
including dynamic loads, between the manufactured home structure and the
hitch-assembly of the towing vehicle. The coupling shall be equipped
with a manually operated mechanism so adapted as to prevent
disengagement of the unit while in operation. The coupling shall be so
designed that it can be disconnected regardless of the angle of the
manufactured home to the towing vehicle. With the manufactured home
parked on level ground, the center of the socket of the coupler shall
not be less than 20 inches nor more than 26 inches from ground level.
(3) Chassis. The chassis, in conjunction with the manufactured home
structure, shall be designed and constructed to effectively sustain the
designed loads consisting of the dead load plus a minimum of 3 pounds
per square foot floor load, (example: free-standing range, refrigerator,
and loose furniture) and the superimposed dynamic load resulting from
highway movement but shall not be required to exceed twice the dead
load. The integrated design shall be capable of insuring rigidity and
structural integrity of the complete manufactured home structure and to
insure against deformation of structural or finish members during the
intended life of the home.
(4) Running gear assembly. (i) The running gear assembly, as part of
the chassis, shall be designed to perform, as a balanced system, in
order to effectively sustain the designed loads set forth in
Sec. 3280.904(b)(3) and to provide for durable dependable safe mobility
of the manufactured home. It shall be designed to accept shock and
vibration, both from the highway and the towing vehicle and effectively
dampen these forces so as to protect the manufactured home structure
from damage and fatigue. Its components shall be designed to facilitate
routine maintenance, inspection and replacement.
(ii) Location of the running gear assembly shall be determined by
documented engineering analysis, taking into account the gross weight
(including all contents), total length of the manufactured home, the
necessary coupling hitch weight, span distance, and turning radius. The
coupling weight shall be not less than 12 percent nor more than 25
percent of the gross weight.
(5) Spring assemblies. Spring assemblies (springs, hangers,
shackles, bushings and mounting bolts) shall be capable of withstanding
all the design loads as outlined in Sec. 3280.904(b)(3) without
exceeding maximum allowable stresses for design spring assembly life as
recommended by the spring assembly manufacturer. The capacity of the
spring system shall assure, that under maximum operating load
conditions, sufficient clearance shall be maintained between the tire
and manufactured home frame or structure to permit unimpeded wheel
movement and for changing tires.
(6) Axles. Axles, and their connecting hardware, shall be capable of
withstanding all of the design loads outlined in Sec. 3280.904(b)(3)
without exceeding maximum allowable stresses for design axle life as
recommended by the axle manufacturer. The number of axles required to
provide a safe tow and good ride characteristics shall be determined and
documented by engineering analysis. Those alternatives listed in
Sec. 3280.903(c) may be accepted in place of such an analysis.
(7) Hubs and bearings. Hubs and bearings shall meet the requirements
of Sec. 3280.904(b)(3) and good engineering practice. Both of these
components shall be accessible for inspection, routine maintenance and
replacement of parts.

[[Page 197]]

(8) Tires, wheels and rims. Tires, wheels and rims shall meet the
requirements of Sec. 3280.904(b)(3). Tires shall be selected for
anticipated usage.
(9) Brake assemblies. (i) The number, type, size and design of brake
assemblies required to assist the towing vehicle in providing effective
control and stopping of the manufactured home shall be determined and
documented by engineering analysis. Those alternatives listed in
Sec. 3280.903(c) may be accepted in place of such an analysis.
(ii) Brakes on the towing vehicle and the manufactured home shall be
capable of assuring that the maximum stopping distance from an initial
velocity of 20 miles per hour does not exceed 40 feet (U.S. Department
of Transportation Regulations).
(10) Lights and associated wiring. Highway safety electrical lights
and associated wiring shall conform to applicable Federal requirements
in terms of location and performance. The manufacturer shall have the
option of meeting this requirement by utilizing a temporary light/wiring
harness provided by the manufactured home transportation carrier.