[Federal Register Volume 72, Number 70 (Thursday, April 12, 2007)]
[Proposed Rules]
[Pages 18446-18456]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-6942]


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DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

49 CFR Parts 107, 171, 172, 173, 176, 178, and 180

[Docket No. PHMSA-2006-25910 (HM-218E)]
RIN: 2137-AE23


Hazardous Materials: Miscellaneous Cargo Tank Motor Vehicle and 
Cylinder Issues; Petitions for Rulemaking

AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), 
DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: PHMSA proposes to amend the Hazardous Materials Regulations 
(HMR; 49 CFR Parts 171-180) to revise certain requirements applicable 
to the manufacture, maintenance, and use of DOT and MC specification 
cargo tank motor vehicles, DOT specification cylinders and UN pressure 
receptacles. The proposed revisions are based on petitions for 
rulemaking submitted by the regulated community and are intended to 
enhance the safe transportation of hazardous materials in commerce, 
clarify regulatory requirements, and reduce operating burdens on cargo 
tank and cylinder manufacturers, requalifiers, carriers, shippers, and 
users.

DATES: Comments must be received by June 11, 2007.

ADDRESSES: You may submit comments identified by the docket number 
PHMSA-2006-25910 (HM-218E) by any of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov. 
Follow the instructions for submitting comments.
     Web Site: http://dms.dot.gov. Follow the instructions for 
submitting comments on the DOT electronic docket site.
     Fax: 1-202-493-2251.
     Mail: Docket Management System; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-001.
     Hand Delivery: To the Docket Management System; Room PL-
401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., 
Washington, DC between 9 a.m. and 5 p.m., Monday through Friday, except 
Federal Holidays.
    Instructions: You must include the agency name and docket number 
PHMSA-2006-25910 (Docket No. HM-218E) or the Regulatory Identification 
Number (RIN) for this notice of proposed rulemaking at the beginning of 
your comment. Please note that all comments received will be posted 
without change to http://dms.dot.gov including any personal information 
provided. See the Privacy Act section of this document.
    Docket: You may view the public docket through the Internet at 
http://dms.dot.gov, or in person at the Docket Management System office 
at the above address.

FOR FURTHER INFORMATION CONTACT: Cameron Satterthwaite or T. Glenn 
Foster, Office of Hazardous Materials Standards, Pipeline and Hazardous 
Materials Safety Administration, U.S. Department of Transportation, 400 
Seventh Street, SW., Washington, DC 20590-0001, telephone (202) 366-
8553.

SUPPLEMENTARY INFORMATION:

I. Background

    The Administrative Procedure Act (APA) requires Federal agencies to 
give interested persons the right to petition for the issuance, 
amendment, or repeal of a rule (5 U.S.C. 553(e)). PHMSA's rulemaking 
procedure regulations, at 49 CFR 106.95, provide for persons to ask 
PHMSA to add, amend or delete a regulation by filing a petition for

[[Page 18447]]

rulemaking containing adequate support for the requested action. In 
this NPRM, PHMSA (also ``we'' or ``us'') proposes to amend the HMR 
based on petitions for rulemaking submitted by cargo tank and cylinder 
manufacturers, requalifiers, shippers, and carriers. We are also 
proposing revisions to address requests for clarification of the 
regulations. These proposed revisions are intended to enhance the safe 
transportation of hazardous materials in cargo tank motor vehicles and 
cylinders, clarify regulatory requirements, and reduce operating 
burdens on carriers, shippers, and users.

II. Summary of Proposals in This NPRM

    The development of this rulemaking was influenced by a wide array 
of correspondence received from persons engaged in the manufacture, 
maintenance, or use of cargo tanks and cylinders. We received petitions 
for rulemaking requesting changes to the cargo tank and cylinder 
requirements specified in the HMR and clarification of existing 
requirements. These petitions are summarized and discussed in the 
following review-by-section summary:

A. Part 171

Updated/Revised/Added Incorporations by Reference (Sec.  171.7)
    We have reviewed the following documents pertaining to cargo tanks 
and compressed gas cylinders. As a result, we have found no provisions 
that would impose a substantial burden or would have an adverse impact 
on safety. Therefore, we are proposing to update, revise, and add the 
following incorporation by reference (IBR) materials in paragraph 
(a)(3) of Sec.  171.7 in the Table of material incorporated by 
reference:
     In response to Western Growers Association (WGA) petition 
P-1352, under the entry ``American Society of Mechanical Engineers,'' 
we propose to revise the reference for ``ASME Code, Sections II (Parts 
A and B), V, VIII (Division 1), and IX of 1998 Edition of American 
Society of Mechanical Engineers Boiler and Pressure Vessel Code'' to 
add a section reference for Sec.  173.5b. See review-by-section 
preamble discussion in Sec.  173.5b for further details.
     In response to WGA petition P-1352, under the entry 
``American Society for Testing and Materials,'' we propose to add 
references to ASTM A53/A53M-06a and ASTM A106/A106M-06a. See review-by-
section preamble discussion in Sec.  173.5b for further details.
     In response to Compressed Gas Association (CGA) petition 
P-1482, under the entry ``Compressed Gas Association, Inc,'' we propose 
to add a reference to CGA, C-1 ``Methods for Hydrostatic Testing of 
Compressed Gas Cylinders,'' 2004 edition. See review-by-section 
preamble discussion in Sec.  180.205 for further details.
     In response to CGA petition P-1489, under the entry 
``Compressed Gas Association, Inc,'' we propose to update CGA G-2.2, 
``Guideline Method for Determining Minimum of 0.2% Water in Anhydrous 
Ammonia,'' from the 1985 Edition to reflect the 1985 Second Edition, 
Reaffirmed 1997. Paragraph (l), in Sec.  173.315, restricts the use of 
MC 330 and MC 331 cargo tanks constructed of quenched and tempered 
``QT'' steel from transporting anhydrous ammonia unless the ammonia has 
the specified minimum water content. The analysis of the water content 
in the ammonia is conducted as prescribed in CGA G-2.2. Currently, CGA 
G-2.2, 1985, Second Edition is incorporated by reference in Sec.  
171.7(a)(3). CGA reaffirmed this publication in 1997. There were no 
changes to the document other than the title reflecting that it was 
reaffirmed in 1997.
     In response to CGA petition P-1488, under the entry 
``Compressed Gas Association, Inc,'' we propose to update CGA P-20, 
``Standard for Classification of Toxic Gas Mixtures'' from the 1995 2nd 
edition to the 2003 3rd edition. See review-by-section preamble 
discussion in Sec.  173.115 for further details.
     In response to CGA petition P-1484, under the entry 
``Compressed Gas Association, Inc,'' we propose to add a reference to 
CGA TB-25 ``Design Considerations for Tube Trailers,'' 2005 edition. 
See review-by-section preamble discussion in Sec.  173.301 for further 
details.
     In response to CGA petition P-1422, under the entry 
``Compressed Gas Association, Inc,'' we propose to add a reference to 
CGA V-9 ``Standard for Compressed Gas Cylinder Valves,'' 2005 edition. 
See review-by-section preamble discussion in Sec. Sec.  173.40 and 
173.301 for further details.
    In response to Tank Trailer Manufacturers Association (TTMA) 
petition P-1408, we are also proposing to revise paragraph (b) of Sec.  
171.7, List of informational materials not requiring incorporation by 
reference, to add a reference to TTMA RP No. 96-01, ``Structural 
Integrity of DOT 406, DOT 407, and DOT 412 Cylindrical Cargo Tanks, 
January 1, 2001 Edition.'' See review-by-section preamble discussion in 
Sec.  178.345-3 for further details.

B. Part 173

Mobile Refrigeration Systems (Sec.  173.5b)
    The agricultural produce industry uses large, mobile refrigeration 
systems on field sites to help preserve freshly harvested fruit and 
vegetables. These refrigeration systems consist of ASME non-DOT 
specification pressure components with a maximum total volumetric 
capacity per vehicle of 2,500 gallons. Refrigerant systems placed in 
service prior to June 1, 1991, have a maximum allowable working 
pressure (MAWP) between 150 to 250 psig; and those placed in service on 
or after June 1, 1991, have an MAWP of 250 psig. The refrigeration 
system, commonly known as vacuum tubes, accumulators, refrigeration 
units, icemakers, pressure coolers or evaporators, primarily use 
Division 2.2 refrigerant gases or anhydrous ammonia in the cooling 
process. The refrigeration systems may or may not be mounted on a motor 
vehicle. These refrigerant systems are operated under special permit, 
SP-10285, which requires each refrigeration system to be visually 
inspected annually and proof pressure tested at least once every two 
years. The Western Growers Association (WGA) P-1352 requests we 
establish design and safety control measures for these refrigeration 
systems consistent with those specified in the special permit and 
provide for their use in the HMR. WGA states these refrigeration 
systems have been authorized under DOT-SP 10285 for highway 
transportation since 1989 and have an exceptional transportation safety 
record. WGA conservatively estimates that in a two-month period, these 
refrigeration systems cool over 18,000,000 cartons of produce valued at 
more than $56 million. We agree with WGA that these portable 
refrigeration systems have a proven safety record under the special 
permit. Therefore, we propose to add a new Sec.  173.5b to authorize 
the transportation of these refrigeration systems subject to the design 
and safety control measures recommended in the petition and prescribed 
in DOT-SP 10285.
Standards for Cylinder Valves (Sec. Sec.  173.40 and 173.301)
    Currently, Sec.  173.40(c) of the HMR requires each cylinder 
containing a poison inhalation hazard (PIH) material in Hazard Zone A 
to be closed with a plug or valve having a taper-threaded connection. 
Each cylinder, with the plug or valve installed, must be capable of 
withstanding the cylinder test

[[Page 18448]]

pressure without damage or leakage, as specified in Sec.  173.40(c). 
CGA (P-1422) requests we add a new paragraph (c)(5) to Sec.  173.40 to 
require cylinders containing a Hazard Zone A material to be closed with 
a plug or a valve conforming to CGA V-9, ``Compressed Gas Association 
Standard for Compressed Gas Cylinder Valves,'' 2005 edition. Section 
173.301 prescribes general requirements for the shipment of compressed 
gases in cylinders and spherical vessels. CGA further requests we 
revise Sec.  173.301(c) to require cylinders containing Hazard Zone A 
and B toxic gases and mixtures to meet the requirements in CGA V-9. CGA 
V-9 defines a cylinder valve as the mechanical device attached to a 
compressed gas cylinder that permits flow into or out of the cylinder 
when the device is in the open position, and prevents flow when it is 
in the closed position. CGA V-9 contains standards on general cylinder 
valve design, design qualification, and performance requirements such 
as operating temperature limits, pressure ranges, and flow 
capabilities. This standard also contains testing and maintenance 
requirements to ensure valves are maintained in a safe working 
condition. CGA V-9 is not applicable to cylinder valves used on non-
refillable cylinders whose valves or inlet connections are permanently 
attached to the cylinders by means of welding or brazing, or to valves 
on cylinders that are horizontally mounted to a chassis or framework 
for road transportation. CGA states use of this publication will 
provide greater assurance that valves used on cylinders containing 
toxic materials are in good condition and properly maintained. Based on 
our review of CGA V-9, we agree with CGA that providing for the use of 
CGA V-9 will assist shippers in the proper selection and use of valves 
installed in DOT specification cylinders containing toxic and various 
types of other gases. Because gases vary in degrees of corrosivity, 
toxicity, and pressure and concentration, a user must use care in 
selecting a cylinder valve appropriate for the cylinder's intended use 
and pressure. The current HMR offer no guidance to users on the proper 
selection of valves. Therefore, we propose to revise Sec. Sec.  
173.40(c) and 173.301(a) to require valves on cylinders, unless 
otherwise excepted, to conform to the requirements in CGA V-9, 
``Standard for Compressed Gas Cylinder Valves,'' 2005 Fifth Edition. We 
also solicit comments on the potential cost impacts, if any, of 
requiring compliance with CGA V-9.
Classification Criteria for Toxic Gas Mixtures (Sec.  173.115)
    In Sec.  173.155(c)(2), the definition for Division 2.3 material 
(gas poisonous by inhalation) provides that LC50 values for 
mixtures may be determined using the formula in Sec.  173.133(b)(1)(i) 
or CGA P-20, ``Standard for Classification of Toxic Gas Mixtures.'' CGA 
(P-1488) requests we update CGA P-20 from the 1995 2nd edition to the 
2003 3rd edition. CGA enclosed a list of changes contained in the 3rd 
edition. These changes align the LC50 values contained in 
CGA P-20 with values contained in the international standards for the 
following materials: Ethylene oxide, Hydrogen fluoride, Methyl amine, 
Nitrogen trioxide, Phosphorous pentafluoride, Phosphorous trifluoride, 
and Tungsten hexafluoride. We agree the petition has merit and propose 
to revise paragraph (c)(2) to reflect the updated CGA P-20, ``Standard 
for Classification of Toxic Gas Mixtures.''
Tube Trailers (Sec.  173.301)
    This section prescribes general requirements for the shipment of 
compressed gases in cylinders and spherical pressure vessels. Paragraph 
(i) of Sec.  173.301 specifies guidelines for cylinders mounted on 
motor vehicles or in frames, commonly referred to as tube trailers. CGA 
(P-1484) requests we revise Sec.  73.301(i) to reference the technical 
bulletin, CGA TB-25, ``Design Considerations for Tube Trailers,'' 2005 
edition. CGA TB-25 addresses protective structures for valves and 
pressure relief devices, and design considerations for the static, 
dynamic, and thermal loads affecting tube trailers. These design 
considerations are intended to reduce the likelihood of the tube 
separating from the trailer and to minimize the unintentional release 
of hazardous materials in the event of a highway collision, including 
but not limited to, a rollover accident. These guidelines are intended 
to promote the reliable operation of the trailers under normal 
conditions and minimize the risk of a catastrophic incident in the 
event of an accident.
    We agree the guidelines contained in CGA TB-25 will enhance the 
safe transportation of tube trailers. CGA developed TB-25 to address 
safety concerns identified following a May 1, 2001 hydrogen gas tube 
trailer incident investigated by the National Transportation Safety 
Board (NTSB). In the incident, certain horizontally mounted cylinders 
on a semi-trailer, along with valves, piping and fittings, were 
damaged, causing the release of hydrogen gas. As a result, NTSB made 
several recommendations to PHMSA in an effort to address safety 
concerns. PHMSA responded to NTSB Recommendation H-02-25 by revising 
ERG Guide 115 in the 2004 Emergency Response Guidebook to include 
information on the difficulty of detecting and extinguishing hydrogen-
fuel fires. As a result, NTSB classified Safety Recommendation H-02-25 
as ``Closed--Acceptable Action.'' NTSB also recommended that PHMSA 
revise Sec.  173.301 to clearly require valves, piping, and fittings 
for cylinders that are horizontally mounted and used to transport 
hazardous materials to be protected from multidirectional forces that 
are likely to occur during accidents, including rollovers (NTSB 
Recommendation H-02-23); and to require cylinders that are used to 
transport hazardous materials and are horizontally mounted on a semi-
trailer to be protected from impact with the roadway or terrain to 
reduce the likelihood of their being fractured and ejected during a 
rollover accident (NTSB Recommendation H-02-24). Accordingly, we 
propose to revise Sec.  173.301(i) to require tube trailers to conform 
to the requirements in CGA TB-25, ``Design Considerations for Tube 
Trailers.'' We also solicit comments on the potential cost impacts, if 
any, of requiring compliance with CGA TB-25.
Requalification of DOT 3BN Cylinders (Sec.  173.338)
    Section 173.338 authorizes the use of DOT 3BN cylinders for the 
shipment of tungsten hexafluoride. Section 173.163 permits cylinders 
used exclusively for hydrogen fluoride to be requalified by external 
visual inspection in place of the periodic volumetric expansion test. 
Air Products (P-1458) requests we permit DOT 3BN cylinders used 
exclusively for tungsten hexafluoride to be requalified by an external 
visual inspection in place of the volumetric expansion test. Air 
Products states the chemical and physical properties of tungsten 
hexafluoride are similar to those of hydrogen fluoride. Air Products 
states noble metal nickel 200 does not corrode in tungsten hexafluoride 
service and the company has never had a cylinder fail a volumetric 
expansion test. We agree with the petitioner that the chemical 
properties of tungsten hexafluoride are similar to those of hydrogen 
fluoride. Tungsten hexafluoride does not corrode nickel; therefore, an 
internal inspection is not warranted. We have authorized DOT 3BN 
cylinders used exclusively for tungsten hexafluoride to be requalified 
by an external visual inspection for several years under special 
permit, SP-

[[Page 18449]]

14016, with satisfactory transportation experience. SP-14016 stipulates 
that DOT 3BN cylinders removed from service must be condemned. 
Therefore, in Sec.  173.338, we propose to permit DOT 3BN cylinders 
used exclusively for tungsten hexafluoride to be requalified by an 
external visual inspection in place of the volumetric expansion test. 
The cylinders must be condemned when removed from service.

C. Part 176

Stowage Requirements for Class 2 Material on Vessels (Sec.  176.200)
    Section 176.200 prescribes general stowage requirements for Class 2 
(Compressed gases) materials transported aboard vessels. Horizon Lines 
(P-1471) requests we prohibit vessel stowage of Division 2.1 (flammable 
gases) in ``reefer units,'' that is, powered refrigerated temperature 
controlled containers. Horizon Lines expresses concern that sparks 
emitted from mechanical components of the reefer unit could come into 
contact with flammable gas in the event of a spill and cause an 
explosion. Horizon Lines further states its concern was substantiated 
by several major manufacturers of reefer units. We agree with the 
petitioner that the stowage of flammable gases in powered refrigerated 
temperature controlled containers should not be permitted without 
adequate safety measures. The transport of hazardous materials in 
temperature controlled containers is addressed in Chapter 7 of the 
International Maritime Dangerous Goods (IMDG) Code. More specifically, 
the IMDG Code, at 7.4 and 7.7 requires the use of refrigeration systems 
with explosion-proof electric fittings within the cooling compartment 
to prevent ignition of flammable vapors. Consistent with the IMDG Code, 
we propose to revise Sec.  176.200 (f) to restrict any package 
containing a Division 2.1 material from transportation in powered 
refrigerated temperature controlled containers, unless the container 
equipment is capable of preventing ignition of flammable vapor by 
having non-sparking or explosion-proof electric fittings within the 
cooling compartment.

D. Part 178

DOT 4E Cylinders (Sec.  178.68)
    Section 178.68 contains the manufacturing specification for DOT 4E 
welded aluminum cylinders. Paragraph (l)(2) specifies the guided bend 
test procedures and rejection criteria to be applied to welds. 
Worthington Cylinders Corp (Worthington) (P-1486) requests we revise 
this paragraph to authorize the use of an alternate bend test 
illustrated in paragraph 12 of The Aluminum Association's publication, 
``Welding Aluminum: Theory and Practice'' for determining the soundness 
of circumferential seam welds on aluminum cylinders. Worthington states 
use of this alternate test will assure the stress is placed on the 
weld, rather than the heat-affected zone of the weld. We agree that 
this alternate bend test is an acceptable test method for aluminum 
cylinders, as well as the currently authorized bend test designed for 
thin-walled steel cylinders. Therefore, we are proposing to revise 
Sec.  178.68(l) to allow the bend test described in The Aluminum 
Association's publication, ``Welding Aluminum: Theory and Practice,'' 
as an alternative test method.
DOT 406, 407, and 412 Cargo Tank Motor Vehicles (Sec.  178.345-3)
    Section 178.345-3 prescribes structural integrity requirements for 
the design and construction of DOT 406, DOT 407, and DOT 412 cargo tank 
motor vehicles. Paragraph (a) specifies the general requirements and 
acceptance criteria for structural integrity. The Tank Trailer 
Manufacturers Association (TTMA) (P-1408) requests we revise paragraph 
(a) to reference TTMA Recommended Practice (RP) No. 96-97, ``Structural 
Integrity of DOT 406, DOT 407, and DOT 412 Cylindrical Cargo Tanks,'' 
December 1, 1997 Edition. This standard contains methods for 
calculating the structural integrity of DOT 406, DOT 407 and DOT 412 
cylindrical cargo tanks in conformance with Sec. Sec.  178.345-3 and 
178.345-8(e). Based on the Federal Motor Carrier Safety 
Administration's review of TTMA RP No. 96-97, we agree with the 
petitioner that using the methods outlined in the publication for 
calculating the structural integrity of cargo tanks will be beneficial 
to manufacturers in reducing time to perform the calculations. 
Therefore, we propose to revise Sec.  178.345-3(a)(3) to reference the 
updated TTMA RP 96-01, 2001 Edition, as suitable guidance for 
performing the structural integrity calculations.
Manhole Assemblies on DOT 406, 407, and 412 Cargo Tank Motor Vehicles 
(Sec.  178.345-5)
    Section 178.345-5 prescribes requirements for manhole assemblies 
used on DOT 406, DOT 407, and DOT 412 cargo tank motor vehicles. 
Paragraph (f) specifies that all fittings and devices mounted on a 
manhole cover, coming in contact with the lading, must withstand the 
same static internal fluid pressure and contain the same permanent 
compliance markings as those prescribed in paragraph (e) for the 
manhole cover. Because paragraph (e) already requires the manhole cover 
to be marked with a statement certifying that the manhole cover meets 
the requirements in Sec.  178.345-5, TTMA (P-1372) requests we remove 
the marking requirement in paragraph (f). We agree with the petitioner 
that the requirement in Sec.  178.345-5(f) to mark the manhole's 
fittings is duplicative of the manhole cover marking requirement in 
paragraph (e). Therefore, we propose to remove the redundant wording in 
paragraph (f).

E. Part 180

Cylinder Requalification (Sec.  180.205)
    Section 180.205 prescribes general requirements for requalification 
of DOT specification cylinders and special permit cylinders. Paragraph 
(g) contains requirements for conducting a periodic pressure test for 
the requalification of cylinders. These requirements include parameters 
for accuracy of the test equipment. CGA requests we revise paragraph 
(g) to reference CGA C-1 ``Methods for Hydrostatic Testing of 
Compressed Gas Cylinders,'' 2004 edition. This CGA publication contains 
hydrostatic testing requirements for the requalification of cylinders.
    We agree the CGA publication more adequately reflects the equipment 
accuracy requirements for performing a pressure test on cylinders. We 
propose to revise Sec.  180.205(g) to reference CGA C-1 for 
requalification of DOT specification cylinders. Section 180.207 
covering UN pressure receptacles also references Sec.  180.205(g) for 
test equipment accuracy. We propose to retain the current requirement 
in paragraph (g) that permits a pressure test to be repeated, in the 
event of test equipment failure only, at a pressure increased by 10%, 
or 100 psi, whichever is the lower value. If repeated, the cumulative 
increase in test pressure may not exceed 10% of minimum prescribed test 
pressure, as noted in CGA C-1. As an example, using a cylinder marked 
``DOT3AA1800'', if the first test is performed exactly at the minimum 
test pressure of 3000 psi (5/3 service pressure), and subsequent tests 
exactly at 3100, 3200, and 3300, a total of three repeat tests could be 
performed. However, if the first test is performed at 3200, one repeat 
test could be performed at 3300. The proposed rule does not alter any 
of the requirements for the operator to ensure the test system is 
accurate and ready to test cylinders. We are retaining the requirements 
contained in current paragraph (g) concerning bands and other removable

[[Page 18450]]

attachments, allowing other calibration standards approved by the 
Associate Administrator, requiring the requalifier to demonstrate 
calibration to an authorized DOT inspector, and the retention of 
calibrated cylinder certificates.
Cargo Tank Testing and Inspection (Sec.  180.407)
    Section 180.407 prescribes requirements for the periodic testing 
and inspection of specification cargo tanks. Paragraph (d)(3) of Sec.  
180.407 requires each reclosing pressure relief valve that is required 
to be removed and tested to be able to open at the required set 
pressure and reseat to a leak-tight condition at 90 percent of the set-
to-discharge pressure or the pressure for the applicable cargo tank 
specification. Paragraph (g)(1)(ii)(A) of Sec.  180.407 requires each 
self-closing pressure relief valve that is an emergency relief vent to 
open at the required set pressure and seat to a leak-tight condition at 
90 percent of the set-to-discharge pressure or the pressure for the 
applicable cargo tank specification. Keehn Service Corporation (Keehn 
Service) (P-1436) states the majority of pressure relief valves 
installed on MC-330 and MC-331 cargo tank motor vehicles transporting 
liquefied petroleum gas have a start-to-discharge set pressure of 250 
psi. Keehn Service states it is difficult for existing or rebuilt 
valves to open at this exact pressure. In fact, a margin of error of as 
much as 4 psig could occur when using a typical 0-400 psig pressure 
gauge. Keehn Service requests we specify a start-to-discharge tolerance 
for pressure relief valves. We agree with the petitioner that it may be 
difficult for a pressure relief valve to function exactly at the 
specified set pressure and that we should allow a margin of error. 
Therefore, we propose to revise paragraphs (d)(3) and (g)(1)(ii)(A), of 
Sec.  180.407, to specify that reclosing and self-closing pressure 
relief valves must be set-to-discharge at a pressure no more than 110% 
of the required set pressure. Providing for a tolerance is consistent 
with the set-to-discharge tolerance allowed for certain other DOT 
specification pressure vessels.

III. Regulatory Analyses and Notices

A. Statutory/Legal Authority for This Rulemaking

    This notice is published under authority of 49 U.S.C. 5103(b), 
which authorizes the Secretary of Transportation to prescribe 
regulations for the safe transportation, including security, of 
hazardous material in intrastate, interstate, and foreign commerce. 
This notice proposes to adopt regulations intended to enhance the safe 
transportation of hazardous materials in cargo tank motor vehicles and 
cylinders, clarify regulatory requirements, and reduce operating 
burdens on carriers, shippers, and users.

B. Executive Order 12866 and DOT Regulatory Policies and Procedures

    This notice of proposed rulemaking is not considered a significant 
regulatory action under section 3(f) of Executive Order 12866 and, 
therefore, was not reviewed by the Office of Management and Budget 
(OMB). This rule is not significant under the Regulatory Policies and 
Procedures of the Department of Transportation (44 FR 11034).
    The proposed rule addresses several petitions for rulemaking 
submitted by the regulated community. For the most part, the 
petitioners request revisions to the HMR that should reduce overall 
compliance costs. For example, several of the petitioners request we 
update industry consensus standards incorporated by reference into the 
HMR. Adoption of industry standards reduces the regulatory burden on 
persons who offer hazardous material for transportation and persons who 
transport hazardous materials in commerce. Industry standards developed 
and adopted by consensus generally are accepted and followed by the 
industry; thus, their incorporation by reference in the HMR assures 
that the industry is not forced to comply with a different set of 
standards to accomplish the same safety goal. In addition, several of 
the petitions request regulatory relief through alternative means of 
compliance with current safety regulations or the elimination of 
requirements that are duplicative, out-dated, or otherwise unnecessary 
for safety. Thus, we are proposing to eliminate a duplicative marking 
requirement for manholes on certain cargo tank motor vehicles and 
provide alternative manufacturing and requalification methods for 
certain cylinders and cargo tank motor vehicles.
    Two of the proposals in this NPRM may result in increased 
compliance costs on the regulated community. We are proposing to 
require valves on cylinders authorized for the transportation of 
hazardous materials to conform to requirements in a CGA consensus 
standard--CGA V-9--applicable to compressed gas cylinder valves. Use of 
the CGA standard will help shippers to select a valve that is 
appropriate for the cylinder's intended use and pressure. Use of the 
correct valve is critical to prevent leaks or failures during 
transportation. We believe that most cylinder users already use the CGA 
consensus standard to guide their valve selection decisions; thus, we 
expect increased compliance costs associated with this proposal to be 
minimal. However, we request comments on the potential costs and 
impacts of requiring compliance with the valve requirements in CGA V-9.
    In addition, we are proposing to address a safety problem involving 
the transportation of hazardous materials in tube trailers through 
adoption of CGA consensus standard TB-24, ``Design Considerations for 
Tube Trailers.'' The CGA standard addresses safety concerns identified 
by NTSB in its investigation of an accident involving tube trailers 
that resulted in the release of hydrogen gas. We anticipate 
transportation of hydrogen gas in tube trailers will increase 
significantly in the coming years to support its use as an alternative 
fuel for automobiles and other vehicles. Ensuring that hydrogen gas 
will be transported safely to suppliers and distribution centers will 
be essential to support its use as an alternative fuel. The CGA 
standard addresses protective structures for valves and pressure relief 
devices and design considerations for static, dynamic, and thermal 
loads affecting tube trailers. The standard is intended to reduce the 
likelihood of the tube trailer separating from its trailer and to 
prevent the unintentional release of hazardous materials in the event 
of a highway collision or rollover accident. Because we are proposing 
to adopt an industry consensus standard that is already in widespread 
use by the industry, we expect compliance costs associated with this 
proposal will be minimal. However, we request comments on the potential 
cost and other impacts of requiring compliance with the CGA standard.
    If adopted, the proposals in this NPRM will enhance transportation 
safety and may reduce the overall compliance burden on the regulated 
industry.

C. Executive Order 13132

    This proposed rule has been analyzed in accordance with the 
principles and criteria contained in Executive Order 13132 
(``federalism''). This proposed rule would preempt State, local, and 
Indian tribe requirements but does not propose any regulation that has 
substantial direct effects on the States, the relationship between the 
national government and the States, or the distribution of power and 
responsibilities among the various levels of government. Therefore, the

[[Page 18451]]

consultation and funding requirements of Executive Order 13132 do not 
apply.
    The Federal hazardous materials transportation law, 49 U.S.C. 5101-
5127, contains an express preemption provision (49 U.S.C. 5125(b)) that 
preempts State, local, and Indian tribe requirements on certain covered 
subjects. Covered subjects are:
    (i) The designation, description, and classification of hazardous 
material;
    (ii) The packing, repacking, handling, labeling, marking, and 
placarding of hazardous material;
    (iii) The preparation, execution, and use of shipping documents 
related to hazardous material and requirements related to the number, 
contents, and placement of those documents;
    (iv) The written notification, recording, and reporting of the 
unintentional release in transportation of hazardous material; or
    (v) The design, manufacture, fabrication, inspection, marking, 
maintenance, reconditioning, repair, or testing of a packaging or 
container represented, marked, certified, or sold as qualified for use 
in transporting hazardous material in commerce.
    This proposed rule addresses covered subject items (v) above and 
preempts State, local, and Indian tribe requirements not meeting the 
``substantively the same'' standard. This proposed rule is necessary to 
update, clarify and provide relief from regulatory requirements.
    Federal hazardous materials transportation law provides at Sec.  
5125(b)(2) that, if DOT issues a regulation concerning any of the 
covered subjects, DOT must determine and publish in the Federal 
Register the effective date of Federal preemption. The effective date 
may not be earlier than the 90th day following the date of issuance of 
the final rule and not later than two years after the date of issuance. 
PHMSA has determined the effective date of Federal preemption for these 
requirements will be 1 year from the date of publication of a final 
rule in the Federal Register.

D. Executive Order 13084

    This proposed rule has been analyzed in accordance with the 
principles and criteria contained in Executive Order 13084 
(``Consultation and Coordination with Indian Tribal Governments''). 
Because this proposed rule does not significantly or uniquely affect 
the communities of the Indian tribal governments and does not impose 
substantial direct compliance costs, the funding and consultation 
requirements of Executive Order 13084 do not apply.

E. Regulatory Flexibility Act, Executive Order 13272, and DOT 
Regulatory Policies and Procedures

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires an 
agency to review regulations to assess their impact on small entities 
unless the agency determines a rule is not expected to have a 
significant impact on a substantial number of small entities. The 
proposed rule incorporates several petitions for rulemaking submitted 
by the regulated community. As specified above, there may be minimal 
increased costs associated with the adoption of CGA V-9 and CGA TB-24. 
However, the revisions as a whole proposed in this rulemaking, if 
adopted, may decrease overall compliance costs for the regulated 
community while enhancing the safe transportation of hazardous 
materials in commerce. Therefore, I certify this rule should not have a 
significant economic impact on a substantial number of small entities.
    This notice has been developed in accordance with Executive Order 
13272 (``Proper Consideration of Small Entities in Agency Rulemaking'') 
and DOT's procedures and policies to promote compliance with the 
Regulatory Flexibility Act to ensure potential impacts of draft rules 
on small entities are properly considered.

F. Paperwork Reduction Act

    PHMSA currently has approved information collections under Office 
of Management and Budget (OMB) Control Number 2137-0014, ``Cargo Tank 
Specification Requirements,'' with an expiration date of November 30, 
2007, and Control Number 2137-0022, ``Testing, Inspection, and Marking 
Requirements for Cylinders,'' with an expiration date of August 31, 
2008. This rule proposes no new information collection and 
recordkeeping requirements.
    Title 5, Code of Federal Regulations requires us to provide 
interested members of the public and affected agencies an opportunity 
to comment on information collection and recordkeeping requests. Under 
the Paperwork Reduction Act, no person is required to respond to an 
information collection unless it has been approved by OMB and displays 
a valid OMB control number.
    Requests for a copy of these information collections should be 
directed to Deborah Boothe or T. Glenn Foster, Office of Hazardous 
Materials Standards (DHM-10), Pipeline and Hazardous Materials Safety 
Administration, Room 8422, 400 Seventh Street, SW., Washington, DC 
20590-0001, Telephone (202) 366-8553.
    All comments should be addressed to the Dockets Unit as identified 
in the ADDRESSES section, and received prior to the close of the 
comment period identified in the DATES section of this rulemaking. In 
addition, you may submit comments specifically related to the 
information collection burden to the PHMSA Desk Officer, Office of 
Management and Budget (OMB), at fax number 202-395-6974. Under the 
Paperwork Reduction Act of 1995, no person is required to respond to an 
information collection unless it displays a valid OMB control number.

G. Regulation Identifier Number (RIN)

    A regulation identifier number (RIN) is assigned to each regulatory 
action listed in the Unified Agenda of Federal Regulations. The 
Regulatory Information Service Center publishes the Unified Agenda in 
April and October of each year. The RIN number contained in the heading 
of this document can be used to cross-reference this action with the 
Unified Agenda.

H. Unfunded Mandates Reform Act

    This proposed rule imposes no unfunded mandates and thus does not 
impose unfunded mandates under the Unfunded Mandates Reform Act of 
1995.

I. Privacy Act

    Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, labor union, etc.). You may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70; Pages 19477-78) or you may visit 
http://dms.dot.gov.

List of Subjects

49 CFR Part 171

    Exports, Hazardous materials transportation, Hazardous waste, 
Imports, Incorporation by reference, Reporting and recordkeeping 
requirements.

49 CFR Part 173

    Hazardous materials transportation, Incorporation by reference, 
Packaging and containers, Radioactive materials, Reporting and 
recordkeeping requirements, Uranium.

49 CFR Part 176

    Hazardous materials transportation, Incorporation by reference, 
Maritime

[[Page 18452]]

carriers, Radioactive materials, Reporting and recordkeeping 
requirements.

49 CFR Part 178

    Hazardous materials transportation, Motor vehicle safety, Packaging 
and containers, Reporting and recordkeeping requirements.

49 CFR Part 180

    Hazardous materials transportation, Incorporation by reference, 
Motor carriers, Motor vehicle safety, Packaging and containers, 
Railroad safety, Reporting and recordkeeping requirements.

    In consideration of the foregoing, 49 CFR Chapter I is proposed to 
be amended as follows:

PART 171--GENERAL INFORMATION, REGULATIONS, AND DEFINITIONS

    1. The authority citation for part 171 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5128, 44701; 49 CFR 1.45 and 1.53; 
Pub. L. 101-410 section 4 (28 U.S.C. 2461 note); Pub L. 104-134 
section 31001.

    2. In Sec.  171.7, make the following changes:
    a. In the table in paragraph (a)(3), under The Aluminum 
Association, a new entry titled ``Welding Aluminum: Theory and 
Practice,'' 2002 Fourth Edition is added;
    b. In the table in paragraph (a)(3), under American Society of 
Mechanical Engineers, the entry titled ``ASME Code, Sections II (Parts 
A and B), V, VIII (Division 1), and IX of 1998 Edition of American 
Society of Mechanical Engineers Boiler and Pressure Vessel Code,'' is 
revised;
    c. In the table in paragraph (a)(3), under American Society for 
Testing and Materials, entries for ASTM A53/A53M-06a and ASTM A106/
A106M-06a are added;
    d. In the table in paragraph (a)(3), under Compressed Gas 
Association, Inc., entries for CGA Pamphlet G-2.2 1985 edition and CGA 
Pamphlet P-20 1995 edition are revised;
    e. In the table in paragraph (a)(3), under Compressed Gas 
Association Inc., new entries for CGA C-1 2005 edition, CGA TB-25 2005 
edition, and CGA V-9 2005 edition are added; and
    f. In paragraph (b), a new entry ``Truck Trailer Manufacturers 
Association,'' 1020 Princess Street, Alexandria, Virginia 22314, ``TTMA 
RP No. 96-01,'' January 1, 2001 Edition is added in alphabetical order.
    The revisions and additions read as follows:


Sec.  171.7  Reference material.

    (a) * * *
    (3) Table of material incorporated by reference. * * *

------------------------------------------------------------------------
      Source and name of material                49 CFR reference
------------------------------------------------------------------------
 
                              * * * * * * *
The Aluminum Association,
 
                              * * * * * * *
    Welding Aluminum: Theory and         178.68.
     Practice, 2002 Fourth Edition.
 
                              * * * * * * *
American Society of Mechanical
 Engineers,
 
                              * * * * * * *
    ASME Code, Sections II (Parts A and  172.102; 173.5b; 173.24b;
     B), V, VIII (Division 1), and IX     173.32; 173.306; 173.315;
     of 1998 Edition of American          173.318; 173.420; 178.245-1;
     Society of Mechanical Engineers      178.245-3; 178.245-4; 178.245-
     Boiler and Pressure Vessel Code.     6; 178.245-7; 178.255-1;
                                          178.255-2; 178.255-14; 178.255-
                                          15; 178.270-2; 178.270-3;
                                          178.270-7; 178.270-9; 178.270-
                                          11; 178.270-12; 178.271-1;
                                          178.272-1; 178.273; 178.274;
                                          178.276; 178.277; 178.320;
                                          178.337-1; 178.337-2; 178.337-
                                          3; 178.337-4; 178.337-6;
                                          178.337-16; 178.337-18;
                                          178.338-1; 178.338-2; 178.338-
                                          3; 178.338-4; 178.338-5;
                                          178.338-6; 178.338-13; 178.338-
                                          16; 178.338-18; 178.338-19;
                                          178.345-1; 178.345-2; 178.345-
                                          3; 178.345-4; 178.345-7;
                                          178.345-14; 178.345-15;
                                          178.346-1; 178.347-1; 178.348-
                                          1; 179.400-3; 180.407.
 
                              * * * * * * *
American Society for Testing and
 Materials,
 
                              * * * * * * *
    ASTM A53/A53M-06a Standard            173.5b.
     Specification for Pipe, Steel,
     Black and Hot-Dipped, Zinc-Coated,
     Welded and Seamless.
 
                              * * * * * * *
    ASTM A106/A106M-06a Standard          173.5b.
     Specification for Seamless Carbon
     Steel Pipe for High-Temperature
     Service.
 
                              * * * * * * *
Compressed Gas Association, Inc.,
 
                              * * * * * * *
    CGA C-1, Methods for Hydrostatic     180.205.
     Testing of Compressed Gas
     Cylinders, 2004 Edition.
 
                              * * * * * * *
    CGA G-2.2, Guideline Method for      173.315.
     Determining Minimum of 0.2% Water
     in Anhydrous Ammonia, 1985, Second
     Edition, Reaffirmed 1997.

[[Page 18453]]

 
 
                              * * * * * * *
    CGA P-20, Standard for the           173.115.
     Classification of Toxic Gas
     Mixtures, 2003, Third Edition.
 
                              * * * * * * *
    CGA TB-25, Design Considerations     173.301.
     for Tube Trailers, 2005 Edition.
 
                              * * * * * * *
    CGA V-9, Standard for Compressed     173.40; 173.301.
     Gas Cylinder Valves, 2005 Fifth
     Edition.
 
                              * * * * * * *
------------------------------------------------------------------------

    (b) List of informational materials not requiring incorporation by 
reference. * * *

------------------------------------------------------------------------
      Source and name of material                49 CFR reference
------------------------------------------------------------------------
 
                              * * * * * * *
Truck Trailer Manufacturers
 Association, 1020 Princess Street,
 Alexandria, Virginia 22314
    TTMA RP No. 96-01, Structural        178.345-3.
     Integrity of DOT 406, DOT 407, and
     DOT 412 Cylindrical Cargo Tanks,
     January, 2001 Edition.
 
                              * * * * * * *
------------------------------------------------------------------------

PART 173--SHIPPERS--GENERAL REQUIREMENTS FOR SHIPMENTS AND 
PACKAGINGS

    The authority citation for part 173 continues to read as follows:


    Authority: 49 U.S.C. 5101-5128, 44701; 49 CFR 1.45, 1.53.

    4. A new Sec.  173.5b is added to read as follows:


Sec.  173.5b  Portable and mobile refrigeration systems.

    This section authorizes the highway transportation of residual 
amounts of Division 2.2 refrigerant gases or anhydrous ammonia 
contained in non-specification pressure vessels that are components of 
refrigeration systems, which may or may not be permanently mounted to a 
transport vehicle, used for agricultural operations. These 
refrigeration systems are used at field sites to cool (pre-cool) 
produce before the produce is loaded into trucks or railcars for market 
or used to supplement stationary refrigeration systems during peak 
harvest times. The components of these refrigeration systems are 
commonly known as vacuum tubes, accumulators, refrigeration units, ice 
makers, pressure coolers, or evaporators.
    (a) General packaging requirements. Each non-specification pressure 
vessel must conform to the following:
    (1) Each pressure vessel must be designed, manufactured, and 
maintained in accordance with applicable requirements of the ASME Code 
(IBR, see Sec.  171.7 of this subchapter).
    (2) Except as authorized in this section, each pressure vessel and 
associated piping must be rated at a maximum allowable work pressure 
(MAWP) of 250 psig. The pressure in these components may not exceed 
MAWP.
    (3) Any part of the piping or pressure vessel separated from 
another component of the refrigeration system by means of a valve, 
blank flange, or other device must be equipped with a pressure relief 
valve set at MAWP. All lines that must be disconnected for 
transportation purposes must be closed by means of a cap, plug or blank 
flange, and valves at the end of disconnected lines must be tightly 
closed.
    (4) The aggregate total volumetric capacity of components within 
the refrigeration system authorized for highway transportation in 
accordance with this section may not exceed 2,500 gallons per vehicle.
    (5) Each pressure vessel and associated piping containing anhydrous 
ammonia must conform to the following:
    (i) Piping with a diameter of 2 inches or more must conform to ASTM 
Specification A53B Schedule 40 (IBR, see Sec.  171.7 of this 
subchapter) or ASTM Specification A106 Schedule 40 (IBR, see Sec.  
171.7 of this subchapter).
    (ii) Piping with a diameter of less than 2 inches must conform to 
ASTM Specification A53B (IBR, see Sec.  171.7 of this subchapter) 
Schedule 80 or ASTM Specification A106 Schedule 80 (IBR, see Sec.  
171.7 of this subchapter).
    (iii) The words ``Inhalation Hazard'' must be marked as required in 
special provision 13 in Sec.  172.102 of this subchapter and, when 
practicable, within 24 inches of the placard.
    (b) Refrigeration systems placed into service prior to June 1, 
1991. (1) For refrigeration systems placed into service prior to June 
1, 1991, each pressure vessel and associated piping for the condensing 
line (``high side'') must be rated at an MAWP of not less than 250 
psig. Each pressure vessel and associated piping for the evaporating 
line (``low side'') must be rated at an MAWP of not less than 150 psig, 
except that each pressure vessel or associated piping that will contain 
refrigerant gas during transportation must be rated at an MAWP of not 
less than 250 psig. During transportation, pressure in the components 
that are part of the evaporating line may not exceed 150 psig.
    (2) Each pressure vessel and associated piping that is part of the

[[Page 18454]]

evaporating line must be marked ``LOW SIDE'' in a permanent and clearly 
visible manner. The evaporating line must have a pressure gauge with 
corresponding temperature markings mounted so as to be easily readable 
when standing on the ground. The gauge must be permanently marked or 
tagged ``SATURATION GAUGE''.
    (3) Each pressure vessel and associated piping with an MAWP of 250 
psig or greater containing liquid anhydrous ammonia must be isolated 
using appropriate means from piping and components marked ``LOW SIDE''.
    (4) Liquid lading is only authorized in system components with a 
rated MAWP of not less than 250 psig.
    (5) Prior to transportation, each pressure vessel and associated 
piping with a rated MAWP of less than 250 psig must be relieved of 
enough gaseous lading to ensure that the MAWP is not exceeded at 
transport temperatures up to 54 [deg]C (130 [deg]F).
    (6) Refrigeration systems placed into service prior to June 1, 
1991, may continue in service until October 1, 2017.
    (c) Prior to transportation over public highways, each pressure 
vessel and associated piping must be drained of refrigerant gas or 
liquid anhydrous ammonia to the extent practicable. Drained contents 
must be recovered in conformance with all applicable environmental 
regulations. Residual liquid anhydrous ammonia in each component may 
not exceed one percent of the component's total volumetric capacity or 
10 gallons, whichever is less.
    (d) System inspection and testing. (1) Each refrigeration system 
authorized under this section must be visually inspected every year. 
The visual inspection must include items listed in Sec.  180.407(d)(2) 
applicable to refrigeration systems. A certificate of the annual visual 
inspection must be dated and signed by the person performing the 
inspection and must contain that person's company affiliation. The 
certificate must remain at the equipment owner's office.
    (2) Each refrigeration system authorized under this section must be 
proof pressure tested every two years beginning with the initial 
pressure test performed after manufacture. Additional pressure tests 
must be performed after any modification, repair or damage to a part of 
the system pressurized with refrigerant gas. System test pressures may 
not be less than one-and-one-half (1.50) times the rated MAWP of the 
system component or piping.
    (3) Pressure relief valves must be successfully tested every two 
years at the MAWP for the components or piping to which they are 
attached. Pressure relief valves may be replaced and marked every 5 
years with valves certified at the appropriate MAWP, in which case the 
valves need not be tested every two years. Valves that do not pass the 
test must be repaired or replaced.
    (e) Test markings and reports. (1) Evidence of testing specified in 
paragraph (d) of this section must be marked on the right forward side 
of the refrigeration system with 2 inch high letters indicating type of 
last test (V = visual; P = pressure: hydrostatic or pneumatic) and the 
month/year in which it was performed. Reports and all of the 
requirements for records of inspections including markings must be 
completed as specified in part 180.
    (2) Pressure relief valves must be durably marked with either the 
date of last test, set-pressure and testing company or the date of last 
replacement, set-pressure, and certifying company, as applicable.
    5. In Sec.  173.40, the introductory text to paragraph (c) is 
revised to read as follows:


Sec.  173.40  General packaging requirements for toxic materials 
packaged in cylinders.

* * * * *
    (c) Closures. When a valve is installed in a DOT specification 
cylinder containing a hazardous material, unless otherwise excepted, 
the valve must conform to the requirements in CGA V-9 (IBR; see Sec.  
171.7 of this subchapter). In addition, each cylinder containing a 
Hazard Zone A material must be closed with a plug or valve conforming 
to the following:
* * * * *
    6. In Sec.  173.115, paragraph (c)(2) is revised to read as 
follows:


Sec.  173.115  Class 2, Divisions 2.1, 2.2, and 2.3--Definitions.

* * * * *
    (c) * * *
    (2) In the absence of adequate data on human toxicity, is presumed 
to be toxic to humans because when tested on laboratory animals it has 
an LC50 value of not more than 5000 mL/m\3\ (see Sec.  
173.116(a) of this subpart for assignment of Hazard Zones A, B, C or 
D). LC50 values for mixtures may be determined using the 
formula in Sec.  173.133(b)(1)(i) or CGA P-20 (IBR, see Sec.  171.7 of 
this subchapter).
* * * * *
    7. In Sec.  173.301, a new paragraph (a)(11) is added and paragraph 
(i) is revised to read as follows:


Sec.  173.301  General requirements for shipment of compressed gases in 
cylinders and spherical pressure vessels.

    (a) * * *
    (11) When a valve is installed in a DOT specification cylinder 
containing a hazardous material, unless otherwise excepted, the valve 
must conform to the requirements in CGA V-9 (IBR; see Sec.  171.7 of 
this subchapter).
* * * * *
    (i) Cylinders mounted in motor vehicles or in frames. (1) MEGCs 
must conform to the requirements in Sec.  173.312. DOT specification 
cylinders mounted on motor vehicles or in frames must conform to the 
requirements specified in this paragraph (i).
    (2) Seamless DOT specification cylinders longer than 2 m (6.5 feet) 
are authorized for transportation only when horizontally mounted on a 
motor vehicle or in an ISO framework or other framework of equivalent 
structural integrity in accordance with CGA TB-25 (IBR, see Sec.  171.7 
of this subchapter). The pressure relief device must be arranged to 
discharge unobstructed to the open air. In addition, for Division 2.1 
(flammable gas) material, the pressure relief devices must be arranged 
to discharge upward to prevent any escaping gas from contacting 
personnel or any adjacent cylinders.
    (3) Cylinders may not be transported by rail in container on 
freight car (COFC) or trailer on flat car (TOFC) service except under 
conditions approved by the Associate Administrator for Safety, Federal 
Railroad Administration.
* * * * *
    8. Section 173.338 is revised to read as follows:


Sec.  173.338  Tungsten hexafluoride.

    (a) Tungsten hexafluoride must be packaged in specification 3A, 
3AA, 3BN, or 3E (Sec. Sec.  178.36, 178.37, 178.39, 178.42 of this 
subchapter) cylinders. Cylinders must be equipped with a valve 
protection cap or be packed in a strong outside container complying 
with the provisions of Sec.  173.40. Outlets of any valves must be 
capped or plugged. As an alternative, the cylinder opening may be 
closed by the use of a metal plug. Specification 3E cylinders must be 
shipped in an overpack that complies with the provisions of Sec.  
173.40.
    (b) In place of the volumetric expansion test, DOT 3BN cylinders 
used in exclusive service may be given a complete external visual 
inspection in conformance with part 180, subpart C, of this subchapter, 
at the time such periodic requalification becomes due. Cylinders that 
undergo a complete external visual inspection, in place of

[[Page 18455]]

the volumetric expansion test, must be condemned in accordance with 
Sec.  180.205 of this subchapter if removed from tungsten hexafluoride 
service.

PART 176--CARRIAGE BY VESSEL

    9. The authority citation for part 176 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5128; 49 CFR 1.53.

    10. In Sec.  176.200, paragraph (f) is revised to read as follows:


Sec.  176.200  General stowage requirements.

* * * * *
    (f) Class 2 (compressed gas) material must be kept as cool as 
practicable and be stowed away from all sources of heat and ignition. 
Any package containing a Division 2.1 (flammable gas) material is 
restricted from transport in powered refrigerated temperature 
controlled containers, unless the equipment is capable of preventing 
ignition of flammable vapors by having non-sparking or explosion-proof 
electric fittings within the cooling compartment.

PART 178--SPECIFICATIONS FOR PACKAGINGS

    11. The authority citation for part 178 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5128; 49 CFR 1.53.

    12. In Sec.  178.68, paragraph (l)(2) is revised to read as 
follows:


Sec.  178.68  Specification 4E welded aluminum cylinders.

* * * * *
    (l) * * *
    (2) Guided bend test. A bend test specimen must be cut from the 
cylinder used for the physical test specified in paragraph (j) of this 
section. Specimen must be taken across the seam, must be a minimum of 
1\1/2\ inches wide, edges must be parallel and rounded with a file, and 
back-up strip, if used, must be removed by machining. The specimen 
shall be tested as follows:
    (i) The specimen must be bent to refusal in the guided bend test 
jig as illustrated in paragraph 6.10 of CGA C-3 (IBR, see Sec.  171.7 
of this subchapter). The root of the weld (inside surface of the 
cylinder) must be located away from the ram of the jig. The specimen 
must not show a crack or other open defect exceeding \1/8\ inch in any 
direction upon completion of the test. Should this specimen fail to 
meet the requirements, specimens may be taken from each of 2 additional 
cylinders from the same lot and tested. If either of the latter 
specimens fails to meet requirements, the entire lot represented must 
be rejected.
    (ii) Alternatively, the specimen may be tested in a guided bend 
test jig as illustrated in paragraph 12 of The Aluminum Association's 
publication, ``Welding Aluminum: Theory and Practice'' (IBR, see Sec.  
171.7 of this subchapter). The root of the weld (inside surface of the 
cylinder) must be located away from the mandrel of the jig. No specimen 
must show a crack or other open defect exceeding \1/8\ inch in any 
direction upon completion of the test. Should this specimen fail to 
meet the requirements, specimens may be taken from each of 2 additional 
cylinders from the same lot and tested. If either of the latter 
specimens fails to meet requirements, the entire lot represented must 
be rejected.
* * * * *
    13. In Sec.  178.345-3, at the end of paragraph (a)(3), a sentence 
is added to read as follows:


Sec.  178.345-3  Structural integrity.

    (a) * * *
    (3) * * * TTMA RP 96-01, Structural Integrity of DOT 406, DOT 407, 
and DOT 412 Cylindrical Cargo Tanks, may be used as guidance in 
performing the calculations.
* * * * *
    14. In Sec.  178.345-5, paragraph (f) is revised to read as 
follows:


Sec.  178.345-5  Manhole assemblies.

* * * * *
    (f) All components mounted on a manhole cover that form part of the 
lading retention structure of the cargo tank wall must withstand the 
same static internal fluid pressure as that required for the manhole 
cover. The component manufacturer shall verify compliance using the 
same test procedure and frequency of testing as specified in Sec.  
178.345-5(b).

PART 180--CONTINUING QUALIFICATION AND MAINTENANCE OF PACKAGINGS

    15. The authority citation for part 180 continues to read as 
follows:

    Authority: 49 U.S.C. 5101-5128; 49 CFR 1.53.

    16. In Sec.  180.205, paragraph (g) is revised to read as follows:


Sec.  180.205  General requirements for requalification of 
specification cylinders.

* * * * *
    (g) Pressure test. Unless otherwise provided, each cylinder 
required to be pressure tested under this subpart must be tested by 
means suitable for measuring the expansion of the cylinder under 
pressure. The pressure test procedures and equipment accuracy for the 
volumetric expansion test and, when authorized, the proof pressure test 
must be in accordance with CGA C-1 (IBR, see Sec.  171.7 of this 
subchapter), subject to the following limitations as applicable:
    (1) Bands and other removable attachments must be loosened or 
removed before testing so that the cylinder is free to expand in all 
directions.
    (2) Each day before testing, the requalifier shall confirm the 
accuracy of the expansion-indicating device and the pressure-indicating 
device by using a calibrated cylinder or other method authorized in 
writing by the Associate Administrator. In the event the calibrated 
cylinder's expansion values have changed from the certified certificate 
expansion values, the calibrated cylinder may be recalibrated using a 
dead weight test device traceable to the National Institute of 
Standards and Testing (NIST) measurement standards or using another 
calibrated cylinder.
    (3) The requalifier must demonstrate calibration in conformance 
with this paragraph (g) to an authorized inspector on any day that the 
requalifier retests cylinders. A requalifier must maintain calibrated 
cylinder certificates in accordance with Sec.  180.215(b)(4).
    (4) When a test pressure cannot be achieved or maintained due to a 
malfunction of the test equipment, the pressure test may be repeated 
only at a pressure increased by 10% or 100 psig, whichever is the lower 
value. The cumulative increase in test pressure may not exceed 10% of 
minimum prescribed test pressure.
    (5) This paragraph (g) does not authorize retest of a cylinder 
otherwise required to be condemned under paragraph (i) of this section.
* * * * *
    In Sec.  180.407, paragraphs (d)(3) and (g)(1)(ii)(A) are revised 
to read as follows:


Sec.  180.407  Requirements for test and inspection of specification 
cargo tanks.

* * * * *
    (d) * * *
    (3) All reclosing pressure relief valves must be externally 
inspected for any corrosion or damage which might prevent safe 
operation. All reclosing pressure relief valves on cargo tanks carrying 
lading corrosive to the valve must be removed from the cargo tank for 
inspection and testing. Each reclosing pressure relief valve required 
to be removed and tested must open at no less than the required set 
pressure and no

[[Page 18456]]

more than 110 percent of the required set pressure and reseat to a 
leak-tight condition at 90 percent of the set-to-discharge pressure or 
the pressure prescribed for the applicable cargo tank specification.
* * * * *
    (g) * * *
    (1) * * *
    (ii) * * *
    (A) Each self-closing pressure relief valve that is an emergency 
relief vent must open at no less than the required set pressure and no 
more than 110 percent of the required set pressure and reseat to a 
leak-tight condition at 90 percent of the set-to-discharge pressure or 
the pressure prescribed for the applicable cargo tank specification.
* * * * *

    Issued in Washington, DC on April 6, 2007 under authority 
delegated in 49 CFR part 106.
Theodore L. Willke,
Acting Associate Administrator for Hazardous Materials Safety.
[FR Doc. E7-6942 Filed 4-11-07; 8:45 am]
BILLING CODE 4910-60-P