Pipeline Safety: Polyamide-11 (PA-11) Plastic Pipe Design Pressures, 1307-1312 [E8-33]

Agencies

• Pipeline and Hazardous Materials Safety Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 73, Number 5 (Tuesday, January 8, 2008)]
[Proposed Rules]
[Pages 1307-1312]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-33]


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DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

49 CFR Part 192

[Docket No. PHMSA--2005--21305, Notice 2]
RIN 2137-AE26


Pipeline Safety: Polyamide-11 (PA-11) Plastic Pipe Design 
Pressures

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

ACTION: Notice of proposed rulemaking.

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SUMMARY: PHMSA proposes to revise the Federal pipeline safety 
regulations to allow certain thermoplastic pipelines made from new 
Polyamide-11 (PA-11) pipe to be designed using a higher design factor 
and to raise the design pressure limit for the same pipelines. Design 
pressure calculations and design pressure limitations for all other 
thermoplastic pipes (PE-polyethylene, PB-polybutylene, PVC-polyvinyl 
chloride, etc.) would remain unchanged. These rule changes would allow 
pipeline operators to operate certain pipelines constructed of new PA-
11 pipe at higher operating pressures than currently allowed by the 
existing rules.

[[Page 1308]]

This would allow pipeline operators to take advantage of the strength 
characteristics of PA-11 pipe.

DATES: Anyone interested in filing written comments on this proposal 
must do so by February 7, 2008. PHMSA will consider late comments filed 
so far as practical.

ADDRESSES: Comments should reference Docket No. PHMSA-2005-21305 and 
may be submitted in the following ways:
     E-Gov Web Site: https://www.regulations.gov. This site 
allows the public to enter comments on any Federal Register notice 
issued by any agency.
     Fax: 1-202-493-2251.
     Mail: Docket Management System: U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue, SE, Washington, DC 20590.
     Hand Delivery: DOT Docket Management System; U.S. 
Department of Transportation, Docket Operations, M-30, West Building 
Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 
20590 between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays.
    Instructions: Identify the docket number, PHMSA-2005-21305, at the 
beginning of your comments. If you submit your comments by mail, submit 
two copies. To receive confirmation that PHMSA received your comments, 
include a self-addressed stamped postcard. Internet users may submit 
comments at https://www.regulations.gov.

    Note: Comments are posted without changes or edits to https://
www.regulations.gov, including any personal information provided. 
There is a privacy statement published on the internet at https://
www.regulations.gov.


FOR FURTHER INFORMATION CONTACT: Richard Sanders at (405) 954-7214, or 
by e-mail at Richard.Sanders@dot.gov; or Wayne Lemoi at (404) 832-1160, 
or by e-mail at Wayne.Lemoi@dot.gov.

SUPPLEMENTARY INFORMATION:

Background

Theoretical Maximum Design Pressure for Plastic Pipe

    Plastic pipe is used to transport various products in both pressure 
and non-pressure applications. In pressure service, such as the 
transport of water or natural gas, the theoretical maximum internal 
design pressure for plastic pipes is independent of the product being 
transported. That is, the theoretical maximum design pressure of a 
plastic pipe is a function of (1) the pipe's physical dimensions and 
(2) the long-term hydrostatic strength (LTHS) of the pipe material.
    The physical dimensions used to calculate the design pressure of a 
plastic pipe are its outside diameter and wall thickness. In practice 
these physical dimensions are often expressed by a standard dimension 
ratio (SDR), which is the ratio of a pipe's average specified outside 
diameter to the minimum specified wall thickness of the pipe. For a 
given pipe diameter, the higher the SDR the thinner the pipe wall. 
Typical SDRs are specified in industry standards developed by the 
American National Standards Institute (ANSI).
    The LTHS used to calculate the design pressure of a plastic pipe is 
usually represented in pipe design formulas by an assigned value known 
as the hydrostatic design basis (HDB). The HDB is a reflection of a 
plastic pipe's ability to resist internal pressure over long periods of 
time. The Hydrostatic Stress Board of the Plastics Pipe Institute (PPI) 
assigns an HDB to a plastic pipe material based on testing of the 
material using the industry accepted test methods published by ASTM 
International. The HDB for various plastic pipes can be found in the 
PPI Technical Report, TR-4, Recommended Hydrostatic Strengths and 
Design Stresses for Thermoplastic Pipe and Fittings Compounds (see 
https://plasticpipe.org/publications/technical_reports.html).

Allowable Design Pressure for Plastic Pipe

    For safety reasons, plastic pipe in any service is not allowed to 
operate up to its theoretical maximum internal design pressure. That 
is, the theoretical maximum design pressure for plastic pipe in service 
is reduced by a safety factor to calculate an allowable design 
pressure, which is the pressure at which a pipe can safely operate. 
Safety factors, commonly referred to as design factors, are generally 
built into plastic pipe design pressure formulas to account for 
unknowns in the pipeline operations and environment. For example, 
plastic pipes used in water service may use a design factor of 0.50, 
which reduces the allowable design pressure to 50 percent of the 
theoretical maximum design pressure. For transporting natural gas, the 
Federal pipeline safety regulations set the design factor at a more 
conservative 0.32 due to the increased hazards associated with 
transporting natural gas as compared to water. This design factor 
limits a plastic pipe's allowable design pressure to 32 percent of its 
theoretical maximum design pressure. This proposed rulemaking would 
increase the design factor for plastic pipe in natural gas service to 
0.40 (40 percent) for certain PA-11 pipe.

Design Pressure Limitations for Plastic Pipe in Natural Gas Service

    For plastic pipe used to transport natural gas, the allowable 
design pressure is limited by the Federal pipeline safety regulations 
in two ways. First, as explained above, the plastic pipe design 
pressure formula in Sec.  192.121 contains a built-in limitation of 
0.32, which limits the allowable design pressure to 32 percent of the 
theoretical maximum design pressure. Second, the allowable design 
pressure calculated using the design formula in Sec.  192.121 cannot 
exceed the design pressure limitations in Sec.  192.123. For plastic 
pipes produced before July 14, 2004, the design pressure cannot exceed 
100 pounds per square inch gauge (psig) (689 kilopascal (kPa)) for 
pipelines in distribution systems and in class 3 or 4 locations. For PE 
2406 and PE 3408 polyethylene thermoplastic pipe produced after July 
14, 2004, the allowable design pressure cannot exceed 125 psig (862 
kPa) for 12-inch iron pipe size (IPS) [nominal pipe diameter] or less. 
This proposed rulemaking would increase the design pressure limit from 
100 psig (689 kPa) to 200 psig (1378 kPa) for certain PA-11 pipe.

Arkema Rulemaking Petitions

    In October 2004 Arkema, Inc. (Arkema), a manufacturer of PA-11 
thermoplastic pipe, submitted two petitions to PHMSA requesting we 
revise 49 CFR 192.121 and 192.123. The first petition requested an 
increase in the design factor from 0.32 to 0.40 in Sec.  192.121 for 
new PA-11 plastic pipes. The second petition requested an increase in 
the design pressure limit in Sec.  192.123 from 100 psig (689 kPa) to 
200 psig (1378 kPa) for new 2-inch IPS, PA-11 plastic pipes. These 
changes would allow new 2-inch IPS, PA-11 pipeline systems to be 
operated up to an allowable design pressure determined by the increased 
design factor of 0.40 or 200 psig (1378 kPa), whichever is less. The 
design factor and design pressure limits for all other plastic pipes 
would remain unchanged.
    Arkema asserted in its petition that new PA-11 material will pose 
less risk to the public at a design factor of 0.40 than older 
thermoplastic piping materials used with a 0.32 design factor. Arkema 
also asserted that allowing an increased design pressure will allow gas 
companies to replace steel pipeline systems with 2-inch plastic pipe 
operating up to 200 psig (1378 kPa), and

[[Page 1309]]

avoid the risk of corrosion failure in steel pipes. A detailed 
technical justification, including performance test results for PA-11 
pipe and a discussion of its history and use, is provided in the 
petitions. This information may be read in docket PHMSA-2005-21305.

Public Comments

    On June 22, 2005, PHMSA published a notice in the Federal Register 
(70 FR 36093) seeking comments on the Arkema petitions. We received 
comments from two operators of PA-11 trial systems, one local gas 
distribution company, the Gas Piping Technology Committee (GPTC), the 
American Gas Association (AGA), the Illinois Commerce Commission (ICC), 
two plastic pipe fitting manufacturers and a plastics pipe consultant. 
All commenters supported the Arkema petitions. The ICC recommended that 
PHMSA consider requiring additional protection to prevent third-party 
damage to higher pressure natural gas lines and suggested adding a 
warning tape or other technology to protect these lines during digging. 
As a result of the public comments and recommendations made by PHMSA's 
staff, Arkema submitted two amended petitions to PHMSA on April 6, 
2006. No public comments have been received for or against Arkema's 
amended petitions, which are discussed in detail below.

Arkema Amended Rulemaking Petitions

    On April 6, 2006, Arkema submitted two amended petitions to PHMSA 
to replace the original petitions of October 2004. The new petitions 
addressed the public comments received by PHMSA and recommendations 
made by PHMSA's staff. In the first amended petition, Arkema requested 
an increase in the design factor in Sec.  192.121 from 0.32 to 0.40 for 
new PA-11 pipe of all pipe diameters with two conditions. First, the 
minimum wall thickness for pipe of a given diameter must be SDR-11 or 
thicker. Second, the rapid crack propagation (RCP) characteristics of 
each new pipe diameter or thicker wall for an already tested diameter 
must be measured using accepted industry standard test methods. Arkema 
subsequently notes that since its original petition, industry test 
methods, including RCP testing, now have been completed to qualify new 
4-inch pipe, which had not been tested at the time of the original 
petition. Therefore, PHMSA proposes to update the regulation to allow 
the revised design factor for new PA-11 up to 4-inch diameter pipe and 
appurtenances.
    Arkema's second amended petition requested a revision to Sec.  
192.123 to allow the use of PA-11 pipe at a maximum allowable operating 
pressure of up to 200 psig (1378 KPa) for SDR-11 pipe at diameters of 
up to 4-inch IPS. This request is based on the availability of complete 
PA-11 piping systems, results from a three-year research program by the 
Gas Technology Institute (GTI) and the successful testing of exhumed 
samples from field installations of PA-11. Therefore, PHMSA is 
proposing to allow the use of PA-11 pipe at a maximum of 200 psig (1378 
kPa). Arkema also supported the ICC recommendation to require warning 
tape and included proposed draft rule language in its amended petition 
to address this issue.

Polyamide-11 (PA-11) Plastic Piping Research and Evaluation

    The GTI sponsored laboratory and field research on PA-11 pipe and 
piping systems beginning in the late 1990s. The research was 
accomplished by Nicor Technologies (Nicor). Final reports on this 
laboratory and field research are in the docket for this rulemaking.
    In 1997, Nicor began with laboratory research on the physical, 
mechanical, and chemical properties of PA-11 pipe materials. Nicor used 
comprehensive laboratory testing and evaluation protocols to examine 
PA-11 pipe materials from three individual production samples and 
concluded that overall ``the results of the comprehensive short term 
and long term testing * * * indicate that PA-11 pipe is a suitable 
plastic alternative to steel systems operating at higher pressure and 
under exposure to high temperatures for a short period of time.''
    Nicor followed up the laboratory research on the properties of PA-
11 pipe materials with additional laboratory and field research on the 
economic feasibility of using PA-11 gas distribution piping systems at 
higher operating pressures and temperatures than currently permitted 
for plastic materials. Nicor performed laboratory tests on numerous PA-
11 fittings and appurtenances. This was followed by the field testing 
of a PA-11 trial piping system installed at a Nicor private test site 
in Illinois, where Nicor installed approximately 400 feet of PA-11 pipe 
using three different installation techniques: Plowing, directional 
boring and open trenching. Nicor concluded that the ``results of the 
trial installation of PA-11 piping system have successfully 
demonstrated that PA-11 piping systems can be safely and effectively 
installed at higher operating pressures.''
    Nicor used the results of the research on the PA-11 trial system to 
petition the ICC and PHMSA for a waiver to install and operate a PA-11 
pipeline system at pressures above 100 psig (689 kPa) in Woodstock, 
Illinois. The ICC and PHMSA approved the waiver. The pipeline was 
installed in December 1999. This has allowed GTI and Nicor to continue 
the research on PA-11 piping systems. This final phase allowed the 
researchers to evaluate the effects of high operating pressures (150 
psig), moisture, aging and other factors on an actual operating natural 
gas pipeline system. The study concluded, ``PA-11 has met or exceeded 
all of the provisions contained within ASTM D2513-99 [American Society 
of Testing Materials, Standard Specification for Thermoplastic Gas 
Pressure Pipe, Tubing, and Fittings, D2513-99] Appendix XI for the use 
of new materials in underground natural gas distribution 
application[s].''
    To continue and expand the research on PA-11, GTI solicited several 
utilities to participate in field trials across the United States. The 
utilities sought and received both Federal and State waivers to allow 
some of the PA-11 trial systems to be designed using a 0.40 design 
factor in the plastic pipe design formula in Sec.  192.121 and to 
operate at pressures above the plastic pipe design limitations in Sec.  
192.123. The PA-11 trial systems were installed from December 1999 to 
November 2004 in Arizona, Illinois, Louisiana, New Mexico, Tennessee 
and Utah in various geographic, climatic and operating temperature and 
pressure environments. Three of the trial systems were designed using a 
design factor of 0.40. One system was designed using an HDB of 1600 
psig at a temperature of 140[deg] F. All the trial systems operate 
between 60 psig (413 kPa) and 200 psig (1378 kPa) with half operating 
above 175 psig (1206 kPa). The GTI final report on this research, 
Utility Participation in PA-11 Evaluation Project, March 2005, is in 
the docket for this rulemaking.

The Proposed Rule

Proposed Regulations

    PHMSA is proposing to change the design pressure limits in 
Sec. Sec.  192.121 and 192.123 for certain PA-11 pipes. The changes 
would allow new 4-inch IPS or less, SDR-11, PA-11 pipelines to be 
designed using a design factor of 0.40 (in lieu of 0.32) in the plastic 
pipe design formulas in Sec.  192.121. The design pressure limit in 
Sec.  192.123 would be raised from 100 psig (689 kPa) to 200 psig (1378 
kPa) for new 4-inch IPS or less, SDR-11, PA-11 plastic pipe used in 
distribution system pipelines and in pipelines in class 3 and 4

[[Page 1310]]

locations. This would allow design pressures up to the design pressure 
calculated in Sec.  192.121 but not greater than 200 psig (1378 kPa). 
All other design pressure limitations would remain unchanged.

Basis for Increasing the Design Factor for PA-11 Plastic Pipe

    When 49 CFR Part 192 was first promulgated in 1970 there were 
multiple design factors for plastic pipe based on the class location in 
which the pipeline was installed. They ranged from 0.20 in class 4 
locations to 0.32 in class 1 locations. In 1977, the Materials 
Transportation Board (MTB) [now PHMSA] proposed a single design factor 
within the range of 0.32 to 0.50 to be used in the plastic pipe design 
formula in Sec.  192.121 (see 42 FR 8386). This single factor would 
allow operators to use the same pipe for identical design pressures 
throughout their systems, thus saving the cost of keeping various pipes 
and matching components in inventory for different class locations. At 
the time of that proposal, some commenters, including the Technical 
Pipeline Safety Standards Committee (TPSSC) suggested that a design 
factor of 0.40 be adopted, based on its many years of satisfactory use 
prior to adoption of the more conservative factor in Sec.  192.121.
    Other commenters favored a single design factor equal to 0.50. This 
view was stated for several reasons, but it was based primarily on the 
fact that plastic pipe did not have a history of pressure failures. 
After considering the several arguments favoring either 0.40 or 0.50, a 
0.32 design factor was adopted. The more conservative increment was 
chosen to protect against unforeseeable events and has remained in 
effect since May 1978.
    The 0.32 design factor was accepted as a conservative value based 
on the state of plastic pipe technology in 1978. Advances in plastic 
pipe technology coupled with the extensive laboratory and field 
research on PA-11 by Nicor under the sponsorship of the GTI, provide 
sufficient evidence that the design factor can be increased to 0.40 for 
certain PA-11 pipes without compromising safety. This evidence includes 
the history of the PA-11 trial systems, which have been operating 
safely for several years at increased operating pressures. Moreover, 
increasing the design factor may allow PA-11 pipe to be used in lieu of 
steel pipe in some locations, thereby reducing corrosion, a primary 
factor in pipeline failures.

Basis for Increasing the Design Pressure Limit for PA-11 Plastic Pipe

    When 49 CFR Part 192 was first promulgated in 1970 the design 
pressure limit for plastic pipe used in distribution systems and class 
3 or 4 locations was set at 100 psig (689 kPa), which was the design 
pressure limit in ANSI B31.8 Standard, Gas Transmission Distribution 
and Piping Systems. The design pressure was raised in 2004 for PE 2406 
and 3408 thermoplastic pipe because of new developments in polyethylene 
materials and better technology for detecting the rate of crack growth, 
i.e., slow crack growth.
    When PHMSA was considering the pressure limit increase for PE 2406 
and PE 3408 thermoplastic pipes, eleven of the commenters on the 
proposed new rule agreed the proposed increase in the design pressure 
limit was warranted. AGA, for example, noted that modern polyethylene 
pipe was already being reliably operated at pressures greater than 100 
psig (689 kPa) under waivers granted by State pipeline safety 
regulators. AGA further contended that the reliability of newer 
polyethylene pipe was supported by laboratory and field analysis of the 
long-term hydrostatic strength of the polyethylene materials.
    Bay State and Northern Natural Gas, two natural gas distribution 
system operators, suggested that the design pressure limit be 
established per International Organization for Standardization (ISO) 
standards, which allow any design pressure permitted by the measured 
HDB. UGI Utilities suggested an even higher maximum allowable pressure. 
However, because there was insufficient data to conclude that pipelines 
operating at such pressures would operate safely, PHMSA concluded that 
prescribing a maximum pressure higher than 125 psig was unsupported at 
that time. The design pressure limit for existing pipe and new pipes 
other than PE 2406 and PE 3408, such as PA-11, remains at 100 psig (689 
kPa).
    As explained above, the design pressure of thermoplastic pipe is a 
function of the physical dimensions and HDB of the pipe. Therefore, for 
plastic pipes of the same physical dimensions, or SDR, the calculated 
design pressure is directly proportional to the HDB. PA-11 has an HDB 
twice that of PE 2406. Therefore, the design pressure of PA-11 
calculated using the plastic pipe design formula in Sec.  192.121 is 
twice the design pressure of PE 2406. For SDR-11 pipe, the calculated 
design pressure of PA-11 is 160 psig, while the design pressure of PE 
2406 is 80 psig. With the current design pressure limit of 100 psig in 
Sec.  192.123 for distribution systems and class 3 or 4 locations, 
however, PA-11 is limited to a design pressure of only 4 percent of its 
HDB while the PE 2406 can operate up to 6.4 percent of its HDB. If PE 
2406 can safely operate at 6.4 percent of its HDB, 80 psig, then it 
stands to reason that PA-11 should also be allowed to operate at 6.4 
percent of its HDB, 160 psig, all else being equal.
    But all else is not equal. Existing regulations allow certain sizes 
of PE 2406 pipes to operate up to 125 psig (10 percent of HDB) in 
distribution systems and class 3 or 4 locations. For example, a PE 
2406, SDR-7 pipeline with a calculated design pressure of 133 psig 
could operate up to 125 psig (10 percent of HDB), but a PA-11, SDR-7 
pipeline would be limited to 100 psig (4 percent of HDB) in the exact 
same application. If the design limits were applied equally based on 
the long-term pressure carrying capability of each pipe, the PA-11, 
SDR-7 pipeline would be allowed to operate up to 250 psig (10 percent 
of HDB).
    The proposed regulation would only allow pipelines constructed from 
4-inch IPS or less, PA-11, SDR-11 pipe to be operated up to 200 psig (8 
percent of HDB). This requires two actions. First, the design factor in 
Sec.  192.121 would have to be raised to 0.40, as explained above, so 
the calculated design pressure will equal 200 psig (1378 kPa). Second, 
the design pressure limit in Sec.  192.123 would have to be raised to 
200 psig (1378 kPa) to allow PA-11 pipelines to operate at 200 psig 
(1378 kPa) in distribution systems and class 3 or 4 locations. PHMSA 
believes these changes would not be inconsistent with pipeline safety 
because the HDB of PA-11 is twice that of PE 2406. Moreover, the 
extensive laboratory and field research, coupled with the successful 
field trial systems, validate that PA-11 pipelines can safely operate 
up to 200 psig (1378 kPa).

Regulatory Analyses and Notices

Privacy Act Statement

    Anyone may search the electronic form of comments received in 
response to any of our dockets by the name of the individual submitting 
the comment (or signing the comment if submitted for an association, 
business, labor union, etc.). You may review the Department of 
Transportation's (DOT) complete Privacy Act Statement in the Federal 
Register published on April 11, 2000 (65 FR 19477).

[[Page 1311]]

Executive Order 12866 and DOT Policies and Procedures

    This proposed rulemaking is not a significant regulatory action 
under section 3(f) of Executive Order 12866 (58 FR 51735) and, 
therefore, was not reviewed by the Office of Management and Budget. 
This proposed rulemaking is not significant under the Regulatory 
Policies and Procedures of the Department of Transportation (44 FR 
11034).
    Installing PA-11 is not mandated; it is optional. PHMSA believes 
operators may choose to install PA-11 pipe, rather than some other type 
of pipe, only if it is the most cost-effective alternative available. 
Consequently, PHMSA anticipates that the benefits of this proposal will 
equal or exceed its costs. Any gas transmission operators with (or 
installing) pipelines in class 3 or 4 locations could potentially be 
affected by the proposed rulemaking. Furthermore, all gas distribution 
operators could potentially be affected by the proposed rule. In total, 
PHMSA estimates that the proposed rule could potentially affect 900 gas 
transmission operators and 1,450 gas distribution system operators. The 
draft economic evaluation is available for review and comment in the 
docket.

Regulatory Flexibility Act

    Under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.), PHMSA 
must consider whether rulemaking actions would have a significant 
economic impact on a substantial number of small entities. PHMSA 
estimates that the proposed rulemaking could potentially affect as many 
as 479 transmission system operators that are small entities, as well 
as 1,131 gas distribution systems that are small entities.
    The proposed rule mandates no action by gas pipeline operators. 
Rather, it provides operators with an option to use PA-11 pipe in 
certain pipeline systems based on economic, operations or other 
considerations. Consequently, the proposal imposes no economic burden 
on these potentially affected gas pipeline operators. PHMSA concludes 
this proposed rulemaking would not have a significant negative economic 
impact on any small entity.

Executive Order 13175

    PHMSA has analyzed this rulemaking according to Executive Order 
13175, ``Consultation and Coordination with Indian Tribal 
Governments.'' Because the proposed rule would not significantly or 
uniquely affect the communities of the Indian tribal governments or 
impose substantial direct compliance costs, the funding and 
consultation requirements of Executive Order 13175 do not apply.

Paperwork Reduction Act

    This proposal does not impose any new information collection 
requirements.

Unfunded Mandates Reform Act of 1995

    This proposed rulemaking does not impose unfunded mandates under 
the Unfunded Mandates Reform Act of 1995. It does not result in costs 
of $100 million or more to either State, local, or tribal governments, 
in the aggregate, or to the private sector, and is the least burdensome 
alternative that achieves the objective of the proposed rulemaking.

National Environmental Policy Act

    PHMSA has analyzed the proposed rulemaking for purposes of the 
National Environmental Policy Act (42 U.S.C. 4321 et seq.) and 
preliminarily determined the proposed rulemaking may provide minor 
beneficial impacts on the quality of the human environment due 
primarily to a potential reduction in corrosion leaks if PA-11 pipe is 
used to replace steel pipe. The draft environmental assessment is 
available for review and comment in the docket. PHMSA will make a final 
determination on environmental impact after reviewing the comments on 
this proposal.

Executive Order 13132

    PHMSA has analyzed the proposed rulemaking according to Executive 
Order 13132 (``Federalism''). The proposal does not have a substantial 
direct effect 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. The proposed 
rulemaking does not impose substantial direct compliance costs on State 
and local governments. This proposed regulation would not preempt state 
law for intrastate pipelines. Therefore, the consultation and funding 
requirements of Executive Order 13132 do not apply.

Executive Order 13211

    Transporting gas impacts the nation's available energy supply. 
However, this proposed rulemaking is not a ``significant energy 
action'' under Executive Order 13211 and is not likely to have a 
significant adverse effect on the supply, distribution, or use of 
energy. Further, the Administrator of the Office of Information and 
Regulatory Affairs has not identified this proposal as a significant 
energy action.

List of Subjects in 49 CFR Part 192

    Gas, Natural gas, Pipelines, Pipeline safety.
    For the reasons provided in the preamble, PHMSA proposes to amend 
49 CFR Part 192 as follows:

PART 192--TRANSPORTATION OF NATURAL GAS AND OTHER GAS BY PIPELINE: 
MINIMUM FEDERAL SAFETY STANDARDS

    1. The authority citation for part 192 continues to read as 
follows:

    Authority: 49 U.S.C. 5103, 60102, 60104, 60108, 60109, 60110, 
60113, 60116, and 60118; and 49 CFR 1.53.
    2. Revise Sec.  192.121 to read as follows:


Sec.  192.121  Design of plastic pipe.

    Subject to the limitations of Sec.  192.123, the design pressure 
for plastic pipe is determined by either of the following formulas:


P = 2 S t (DF) / (D-t)

P = 2S (DF) / (SDR-1)

Where:
    P = Design pressure, gauge, psig (kPa).
    S = For thermoplastic pipe, the HDB is determined in accordance 
with the listed specification at a temperature equal to 73[deg] F 
(23[deg] C), 100[deg] F (38[deg] C), 120[deg] F (49[deg] C), or 
140[deg] F (60[deg] C). In the absence of an HDB established at the 
specified temperature, the HDB of a higher temperature may be used 
in determining a design pressure rating at the specified temperature 
by arithmetic interpolation using the procedure in Part D.2 of PPI 
TR-3/2004, HDB/PDB/SDB/MRS Policies (incorporated by reference, see 
Sec.  192.7). For reinforced thermosetting plastic pipe, 11,000 psig 
(75,842 kPa).
    t = Specified wall thickness, inches (mm).
    D = Specified outside diameter, inches (mm).
    SDR = Standard dimension ratio, the ratio of the average 
specified outside diameter to the minimum specified wall thickness, 
corresponding to a value from a common numbering system that was 
derived from the American National Standards Institute preferred 
number series 10.
    D F = 0.32, or = 0.40 for nominal pipe size (IPS) 4 or less, 
SDR-11, polyamide-11 (PA-11) pipe produced after February 7, 2008 
only.

    3. Amend Sec.  192.123 to revise paragraph (a) introductory text 
and to add a new paragraph (f) to read as follows:


Sec.  192.123  Design limitations for plastic pipe.

    (a) Except as provided in paragraph (e) and paragraph (f) of this 
section, the design pressure may not exceed a gauge pressure of 100 
psig (689 kPa) for plastic pipe used in:
* * * * *

[[Page 1312]]

    (f) The design pressure for polyamide-11 (PA-11) pipe produced 
after February 7, 2008 may exceed a gauge pressure of 100 psig (689 
kPa) provided that:
    (1) The design pressure does not exceed 200 psig (1378 kPa);
    (2) The pipe size is nominal pipe size (IPS) 4-inch or less;
    (3) The pipe has a standard dimension ratio of SDR-11 only; and
    (4) Pipes with design pressures above 100 psig (689 kPa) shall be 
buried with a warning tape or other device sufficient to warn an 
excavator of the presence of a high pressure gas line near the tape or 
other device before reaching the burial depth of the pipeline.

    Issued in Washington, DC, on December 27, 2007.
Jeffrey D. Wiese,
Associate Administrator for Pipeline Safety.
 [FR Doc. E8-33 Filed 1-7-08; 8:45 am]
BILLING CODE 4910-60-P