[Title 29 CFR 1910.29]
[Code of Federal Regulations (annual edition) - July 1, 2002 Edition]
[Title 29 - LABOR]
[Subtitle B - Regulations Relating to Labor (Continued)]
[Chapter Xvii - OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT]
[Part 1910 - OCCUPATIONAL SAFETY AND HEALTH STANDARDS]
[Subpart D - Walking-Working Surfaces]
[Sec. 1910.29 - Manually propelled mobile ladder stands and scaffolds (towers).]
[From the U.S. Government Printing Office]


29LABOR52002-07-012002-07-01false1910.29Sec. 1910.29LABORRegulations Relating to Labor (Continued)OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENTOCCUPATIONAL SAFETY AND HEALTH STANDARDSWalking-Working Surfaces
Sec. 1910.29  Manually propelled mobile ladder stands and scaffolds (towers).

    (a) General requirements--(1) Application. This section is intended 
to prescribe rules and requirements for the design, construction, and 
use of mobile work platforms (including ladder stands but not including 
aerial ladders) and rolling (mobile) scaffolds (towers). This standard 
is promulgated to aid in providing for the safety of life, limb, and 
property, by establishing minimum standards for structural design 
requirements and for the use of mobile work platforms and towers.
    (2) Working loads. (i) Work platforms and scaffolds shall be capable 
of carrying the design load under varying circumstances depending upon 
the conditions of use. Therefore, all parts and appurtenances necessary 
for their safe and efficient utilization must be integral parts of the 
design.
    (ii) Specific design and construction requirements are not a part of 
this section because of the wide variety of materials and design 
possibilities. However, the design shall be such as to produce a mobile 
ladder stand or scaffold that will safely sustain the specified loads. 
The material selected shall be of sufficient strength to meet the test 
requirements and shall be protected against corrosion or deterioration.
    (a) The design working load of ladder stands shall be calculated on 
the basis of one or more 200-pound persons together with 50 pounds of 
equipment each.
    (b) The design load of all scaffolds shall be calculated on the 
basis of:

    Light-- Designed and constructed to carry a working load of 25 
pounds per square foot.
    Medium-- Designed and constructed to carry a working load of 50 
pounds per square foot.

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    Heavy-- Designed and constructed to carry a working load of 75 
pounds per square foot.


All ladder stands and scaffolds shall be capable of supporting at least 
four times the design working load.
    (iii) The materials used in mobile ladder stands and scaffolds shall 
be of standard manufacture and conform to standard specifications of 
strength, dimensions, and weights, and shall be selected to safely 
support the design working load.
    (iv) Nails, bolts, or other fasteners used in the construction of 
ladders, scaffolds, and towers shall be of adequate size and in 
sufficient numbers at each connection to develop the designed strength 
of the unit. Nails shall be driven full length. (All nails should be 
immediately withdrawn from dismantled lumber.)
    (v) All exposed surfaces shall be free from sharp edges, burrs or 
other safety hazards.
    (3) Work levels. (i) The maximum work level height shall not exceed 
four (4) times the minimum or least base dimensions of any mobile ladder 
stand or scaffold. Where the basic mobile unit does not meet this 
requirement, suitable outrigger frames shall be employed to achieve this 
least base dimension, or provisions shall be made to guy or brace the 
unit against tipping.
    (ii) The minimum platform width for any work level shall not be less 
than 20 inches for mobile scaffolds (towers). Ladder stands shall have a 
minimum step width of 16 inches.
    (iii) The supporting structure for the work level shall be rigidly 
braced, using adequate cross bracing or diagonal bracing with rigid 
platforms at each work level.
    (iv) The steps of ladder stands shall be fabricated from slip 
resistant treads.
    (v) The work level platform of scaffolds (towers) shall be of wood, 
aluminum, or plywood planking, steel or expanded metal, for the full 
width of the scaffold, except for necessary openings. Work platforms 
shall be secured in place. All planking shall be 2-inch (nominal) 
scaffold grade minimum 1,500 f. (stress grade) construction grade lumber 
or equivalent.
    (vi) All scaffold work levels 10 feet or higher above the ground or 
floor shall have a standard (4-inch nominal) toeboard.
    (vii) All work levels 10 feet or higher above the ground or floor 
shall have a guardrail of 2- by 4-inch nominal or the equivalent 
installed no less than 36 inches or more than 42 inches high, with a 
mid-rail, when required, of 1- by 4-inch nominal lumber or equivalent.
    (viii) A climbing ladder or stairway shall be provided for proper 
access and egress, and shall be affixed or built into the scaffold and 
so located that its use will not have a tendency to tip the scaffold. A 
landing platform shall be provided at intervals not to exceed 30 feet.
    (4) Wheels or casters. (i) Wheels or casters shall be properly 
designed for strength and dimensions to support four (4) times the 
design working load.
    (ii) All scaffold casters shall be provided with a positive wheel 
and/or swivel lock to prevent movement. Ladder stands shall have at 
least two (2) of the four (4) casters and shall be of the swivel type.
    (iii) Where leveling of the elevated work platform is required, 
screw jacks or other suitable means for adjusting the height shall be 
provided in the base section of each mobile unit.
    (b) Mobile tubular welded frame scaffolds--(1) General. Units shall 
be designed to comply with the requirements of paragraph (a) of this 
section.
    (2) Bracing. Scaffolds shall be properly braced by cross braces and/
or diagonal braces for securing vertical members together laterally. The 
cross braces shall be of a length that will automatically square and 
align vertical members so the erected scaffold is always plumb, square, 
and rigid.
    (3) Spacing. Spacing of panels or frames shall be consistent with 
the loads imposed. The frames shall be placed one on top of the other 
with coupling or stacking pins to provide proper vertical alignment of 
the legs.
    (4) Locking. Where uplift may occur, panels shall be locked together 
vertically by pins or other equivalent means.
    (5) Erection. Only the manufacturer of a scaffold or his qualified 
designated

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agent shall be permitted to erect or supervise the erection of scaffolds 
exceeding 50 feet in height above the base, unless such structure is 
approved in writing by a registered professional engineer, or erected in 
accordance with instructions furnished by the manufacturer.
    (c) Mobile tubular welded sectional folding scaffolds--(1) General. 
Units including sectional stairway and sectional ladder scaffolds shall 
be designed to comply with the requirements of paragraph (a) of this 
section.
    (2) Stairway. An integral stairway and work platform shall be 
incorporated into the structure of each sectional folding stairway 
scaffold.
    (3) Bracing. An integral set of pivoting and hinged folding diagonal 
and horizontal braces and a detachable work platform shall be 
incorporated into the structure of each sectional folding ladder 
scaffold.
    (4) Sectional folding stairway scaffolds. Sectional folding stairway 
scaffolds shall be designed as medium duty scaffolds except for high 
clearance. These special base sections shall be designed as light duty 
scaffolds. When upper sectional folding stairway scaffolds are used with 
a special high clearance base, the load capacity of the entire scaffold 
shall be reduced accordingly. The width of a sectional folding stairway 
scaffold shall not exceed 4\1/2\ feet. The maximum length of a sectional 
folding stairway scaffold shall not exceed 6 feet.
    (5) Sectional folding ladder scaffolds. Sectional folding ladder 
scaffolds shall be designed as light duty scaffolds including special 
base (open end) sections which are designed for high clearance. For 
certain special applications the six-foot (6[min]) folding ladder 
scaffolds, except for special high clearance base sections, shall be 
designed for use as medium duty scaffolds. The width of a sectional 
folding ladder scaffold shall not exceed 4\1/2\ feet. The maximum length 
of a sectional folding ladder scaffold shall not exceed 6 feet 6 inches 
for a six-foot (6[foot]) long unit, 8 feet 6 inches for an eight-foot 
(8[foot]) unit or 10 feet 6 inches for a ten-foot (10[foot]) long unit.
    (6) End frames. The end frames of sectional ladder and stairway 
scaffolds shall be designed so that the horizontal bearers provide 
supports for multiple planking levels.
    (7) Erection. Only the manufacturer of the scaffold or his qualified 
designated agent shall be permitted to erect or supervise the erection 
of scaffolds exceeding 50 feet in height above the base, unless such 
structure is approved in writing by a licensed professional engineer, or 
erected in accordance with instructions furnished by the manufacturer.
    (d) Mobile tube and coupler scaffolds--(1) Design. Units shall be 
designed to comply with the applicable requirements of paragraph (a) of 
this section.
    (2) Material. The material used for the couplers shall be of a 
structural type, such as a drop-forged steel, malleable iron or 
structural grade aluminum. The use of gray cast iron is prohibited.
    (3) Erection. Only the manufacturer of the scaffold or his qualified 
designated agent shall be permitted to erect or supervise the erection 
of scaffolds exceeding 50 feet in height above the base, unless such 
structure is approved in writing by a licensed professional engineer, or 
erected in accordance with instructions furnished by the manufacturer.
    (e) Mobile work platforms--(1) Design. Units shall be designed for 
the use intended and shall comply with the requirements of paragraph (a) 
of this section.
    (2) Base width. The minimum width of the base of mobile work 
platforms shall not be less than 20 inches.
    (3) Bracing. Adequate rigid diagonal bracing to vertical members 
shall be provided.
    (f) Mobile ladder stands--(1) Design. Units shall comply with 
applicable requirements of paragraph (a) of this section.
    (2) Base width. The minimum base width shall conform to paragraph 
(a)(3)(i) of this section. The maximum length of the base section shall 
be the total length of combined steps and top assembly, measured 
horizontally, plus five-eighths inch per step of rise.
    (3) Steps. Steps shall be uniformly spaced, and sloped, with a rise 
of not less than nine (9) inches, nor more than ten (10) inches, and a 
depth of not less seven (7) inches. The slope of the steps section shall 
be a minimum of fifty-

[[Page 148]]

five (55) degrees and a maximum of sixty (60) degrees measured from the 
horizontal.
    (4) Handrails. (i) Units having more than five (5) steps or 60 
inches vertical height to the top step shall be equipped with handrails.
    (ii) Handrails shall be a minimum of 29 inches high. Measurements 
shall be taken vertically from the center of the step.
    (5) Loading. The load (see paragraph (a)(2)(ii)(a) of this section) 
shall be applied uniformly to a 3\1/2\ inches wide area front to back at 
the center of the width span with a safety factor of four (4).