Pipeline Safety: Updated Notification of the Susceptibility to Premature Brittle-Like Cracking of Older Plastic Pipe, 51301-51303 [07-4309]

Download as PDF Federal Register / Vol. 72, No. 172 / Thursday, September 6, 2007 / Notices safety procedures used for filling, operating, and discharging MATs to determine whether additional safety procedures should be implemented. To this end, we request that persons who use such transportation systems to provide us with information on the effectiveness of the current DOT regulations, consensus standards, and industry best practices. We are also interested in any other procedures utilized to ensure that operations related to the transportation of acetylene on MATs are performed safely. We would also like to work with shippers, carriers, and facilities that receive shipments of acetylene in MATs to develop and implement a pilot program to test the effectiveness of current or alternative procedures or methods designed to enhance the safety of transportation operations involving acetylene on MATs. As part of this program, we will assist individual companies or facilities to evaluate the effectiveness of their current procedures and to identify additional measures that should be implemented. We welcome suggestions concerning how such a program should be structured and the entities that should participate. To ensure that our message reaches all stakeholders affected by these risks, we plan to communicate this advisory through our public affairs notification and outreach processes. For additional visibility, we have made this advisory available on the PHMSA homepage at https://www.phmsa.dot.gov and the DOT electronic docket site at https:// dms.dot.gov. In addition, if you are aware of other companies that are involved in the charging, operating, and discharging MATs, please share this advisory notice with them and, if possible, identify them in your correspondence with this agency. We believe a collaborative effort involving an integrated and cooperative approach will help us to address safety risks, reduce incidents, enhance safety, and protect the public. mstockstill on PROD1PC66 with NOTICES Issued in Washington, DC on August 30, 2007. Theodore L. Willke, Associate Administrator for Hazardous Materials Safety. [FR Doc. 07–4355 Filed 9–5–07; 8:45 am] BILLING CODE 4910–60–P VerDate Aug<31>2005 18:25 Sep 05, 2007 Jkt 211001 DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No. PHMSA–2004–19856] Pipeline Safety: Updated Notification of the Susceptibility to Premature Brittle-Like Cracking of Older Plastic Pipe Pipeline and Hazardous Materials Safety Administration (PHMSA); DOT. ACTION: Notice; Issuance of Advisory Bulletin. AGENCY: SUMMARY: PHMSA is issuing this updated advisory bulletin to owners and operators of natural gas pipeline distribution systems concerning the susceptibility of older plastic pipe to premature brittle-like cracking. PHMSA previously issued three advisory bulletins on this subject: Two on March 11, 1999 and one on November 26, 2002. This advisory bulletin expands on the information provided in the three prior bulletins by listing two additional pipe materials with poor performance histories relative to brittle-like cracking and by updating pipeline owners and operators on the ongoing voluntary efforts to collect and analyze data on plastic pipe performance. Owners and operators of natural gas pipeline distribution systems are encouraged to review the three previous advisory bulletins in their entirety. FOR FURTHER INFORMATION CONTACT: Richard Sanders at (405) 954–7214, or by e-mail at richard.sanders@dot.gov. SUPPLEMENTARY INFORMATION: I. National Transportation Safety Board (NTSB) Investigation On April 23, 1998, the National Transportation Safety Board (NTSB) issued its Special Investigation Report, Brittle-Like Cracking in Plastic Pipe for Gas Service, NTSB/SIR–98/01. The report described the results of the NTSB’s special investigation of polyethylene gas service pipe, which addressed three major safety issues: (1) Vulnerability of plastic piping to premature failures due to brittle-like cracking; (2) adequacy of available guidance relating to the installation and protection of plastic piping connections to steel mains; and, (3) effectiveness of performance monitoring of plastic pipeline systems to detect unacceptable performance in piping systems. (1) Vulnerability of plastic piping to premature failures due to brittle-like cracking: The NTSB found that failures in polyethylene pipe in actual service are frequently brittle-like, slit failures, PO 00000 Frm 00090 Fmt 4703 Sfmt 4703 51301 not ductile failures. It concluded the number and similarity of plastic pipe accident and non-accident failures indicate past standards used to rate the long-term strength of plastic pipe may have overrated the strength and resistance to brittle-like cracking for much of the plastic pipe manufactured and used for gas service from the 1960s through the early 1980s. The NTSB also concluded any potential public safety hazards from these failures are likely to be limited to locations where stress intensification exists. The NTSB went on to state that more durable modern plastic piping materials and better strength testing have made the strength ratings of modern plastic piping more reliable. (2) Adequacy of available guidance relating to the installation and protection of plastic piping connections to steel mains: The NTSB concluded that gas pipeline operators had insufficient notification of the brittlelike failure potential for plastic pipe manufactured and used for gas service from the 1960s to the early 1980s. The NTSB also concluded this may not have allowed companies to implement adequate surveillance and replacement programs for older plastic piping. The NTSB explained the Gas Research Institute (GRI) developed a significant amount of data on older plastic pipe but the data was published in codified terms making it insufficient for use by pipeline system operators. The NTSB recommended that manufacturers of resin and pipe, industry trade groups and the Federal government do more to alert pipeline operators to the role played by stress intensification from external forces in the premature failure of plastic pipe due to brittle-like cracking. (3) Effectiveness of performance monitoring of plastic pipeline systems as a way of detecting unacceptable performance in piping systems: The NTSB’s analysis noted that Federal regulations require pipeline operators to have an ongoing program to monitor the performance of their pipeline systems. However, the NTSB investigation revealed some gas pipeline operators’ performance monitoring programs did not effectively collect and analyze data to determine the extent of possible hazards associated with plastic pipeline systems. The NTSB pointed out, ‘‘such a program must be adequate to detect trends as well as to identify localized problem areas, and it must be able to relate poor performance to specific factors such as plastic piping brands, dates of manufacture (or installation dates), and failure conditions.’’ E:\FR\FM\06SEN1.SGM 06SEN1 51302 Federal Register / Vol. 72, No. 172 / Thursday, September 6, 2007 / Notices mstockstill on PROD1PC66 with NOTICES Copies of this report may be obtained by searching the NTSB Web site at www.ntsb.gov. II. Advisory Bulletins Previously Issued by PHMSA The NTSB made several recommendations to PHMSA and to trade organizations in its 1998 special investigation report. In response, PHMSA issued three advisory bulletins. The first advisory bulletin, ADB–99–01, Potential Failure Due to Brittle-Like Cracking of Certain Polyethylene Plastic Pipe Manufactured by Century Utility Products Inc, was published in the Federal Register (FR) on March 11, 1999 (64 FR 12211) to advise natural gas pipeline distribution system operators that brittle-like cracking may occur on certain polyethylene pipe manufactured by Century Utility Products, Inc. The second advisory bulletin, ADB– 99–02, Potential Failures Due to BrittleLike Cracking of Older Plastic Pipe in Natural Gas Distribution Systems, was also published in the Federal Register on March 11, 1999 (64 FR 12212) to advise natural gas pipeline distribution system operators of the potential for brittle-like cracking of plastic pipes installed between the 1960s and early 1980s. The third advisory bulletin, ADB–02– 07, Notification of the Susceptibility To Premature Brittle-Like Cracking of Older Plastic Pipe, was published in the Federal Register on November 26, 2002 (67 FR 70806) to reiterate to natural gas pipeline distribution system operators the susceptibility of older plastic pipe to premature brittle-like cracking. The older polyethylene pipe materials specifically identified in ADB–02–07 included, but were not limited to: • Century Utility Products, Inc. products; • Low-ductile inner wall ‘‘Aldyl A’’ piping manufactured by DuPont Company before 1973; and • Polyethylene gas pipe designated PE 3306. This third advisory bulletin also listed several environmental, installation and service conditions in which plastic piping is used that could lead to premature brittle-like cracking failure. PHMSA also described six recommended practices for polyethylene gas pipeline system operators to aid them with identifying and managing brittle-like cracking problems. III. Plastic Pipe Studies Beginning January 25, 2001, the American Gas Association (AGA) began to collect data on in-service plastic piping material failures with the VerDate Aug<31>2005 18:25 Sep 05, 2007 Jkt 211001 objective of identifying trends in the performance of these materials. The resulting leak survey data, collected from 2001 to present, on the county’s natural gas distribution systems includes both actual failure information and negative reports (reports of no leads) submitted voluntarily by participating pipeline operating companies. The AGA, PHMSA, and other industry and state organizations continue to collect and analyze the data. Unfortunately, the data cannot be correlated with the quantities of each plastic pipe material that may be in service across the United States. Therefore, the data does not assess the failure rates of individual plastic pipe materials on a linear basis (i.e. per foot, per mile, etc.). However, the failure data reinforces what is historically known about certain older plastic piping and components. The data also indicates the susceptibility of additional specific materials to brittle-like cracking. IV. Advisory Bulletin ADB–07–01 To: Owners and Operators of Natural Gas Pipeline Distribution Systems. Subject: Updated Notification of the Susceptibility of Older Plastic Pipes to Premature Brittle-Like Cracking. Advisory: All owners and operators of natural gas distribution systems who have installed and operate plastic piping are reminded of the phenomenon of brittle-like cracking. Brittle-like cracking refers to crack initiation in the pipe wall not immediately resulting in a full break followed by stable crack growth at stress levels much lower than the stress required for yielding. This results in very tight, slit-like, openings and gas leaks. Although significant cracking may occur at points of stress concentration and near improperly designed or installed fittings, small brittle-like cracks may be difficult to detect until a significant amount of gas leaks out of the pipe, and potentially migrates into an enclosed space such as a basement. Premature brittle-like cracking requires relatively high localized stress intensification that may result from geometrical discontinuities, excessive bending, improper installation of fittings, dents and/or gouges. Because this failure mode exhibits no evidence of gross yielding at the failure location, the term brittle-like cracking is used. This phenomenon is different from brittle fracture, in which the pipe failure causes fragmentation of the pipe. All owners and operators of natural gas distribution systems are future advised to review the three earlier advisory bulletins on this issue. In addition to being available in the PO 00000 Frm 00091 Fmt 4703 Sfmt 4703 Federal Register, these advisory bulletins are available in the docket, and on PHMSA’s Web site at https:// phmsa.dot.gov/ under Pipeline Safety Regulations. In the first advisory bulletin, ADB– 99–01, published on March 11, 1999 (64 FR 12211), PHMSA advises natural gas distribution system operators of the potential for poor resistance to brittlelike cracking of certain polyethylene pipe manufactured by Century Utility Products, Inc. In the second advisory bulletin, ADB–99–02, published on March 11, 1999 (64 FR 12212), PHMSA advises natural gas distribution system operators of the potential for brittle-like cracking of plastic pipes installed between the 1960s and early 1980s. In the third advisory bulletin, ADB– 02–07, published on November 26, 2002 (67 FR 70806), PHMSA reiterates to pipeline operators the susceptibility of some older plastic pipe to premature brittle-like cracking which could substantially reduce the service life of natural gas distribution systems and to explain the mission of the Plastic Pipe Database Committee (PPDC) ‘‘to develop and maintain a voluntary data collection process that supports the analysis of the frequency and causes of in-service plastic piping material failures.’’ The advisory bulletin also lists several environmental, installation and service conditions under which plastic piping is used which is used which could lead to premature brittle-like cracking failure. PHMSA also describes six recommended practices for polyethylene gas pipeline system operators to aid them with identifying and managing brittle-like cracking problems. Lastly, the susceptibility of some polyethylene pipes to brittle-like cracking is dependent on the resin, pipe processing, and service conditions. As noted in ADB–02–07, these older polyethylene pipe materials include, but are not limited to: • Century Utility Products, Inc. products; • Low-ductile inner wall ‘‘Aldyl A’’ piping manufactured by DuPont Company before 1973; and • Polyethylene gas pipe designated PE 3306. The data now supports adding the following pipe materials to this list: • Delrin insert tap tees; and, • Plexco service tee Celcon (polyacetal) caps. Authority: 49 U.S.C. chapter 601 and 49 CFR 1.53. E:\FR\FM\06SEN1.SGM 06SEN1 Federal Register / Vol. 72, No. 172 / Thursday, September 6, 2007 / Notices Issued in Washington, DC, on August 28, 2007. Jeffrey D. Wiese, Associate Administrator for Pipeline Safety. [FR Doc. 07–4309 Filed 9–5–07; 8:45 am] BILLING CODE 4910–60–M DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No. PHMSA–2007–28993] Pipeline Safety: Adequacy of Internal Corrosion Regulations for Hazardous Liquid Pipelines Pipeline and Hazardous Materials Safety Administration (PHMSA), U.S. Department of Transportation (DOT). ACTION: Notice of availability of materials; request for comments. AGENCY: Submit comments by October 9, 2007. Comments should reference Docket No. PHMSA–2007–28993 and may be submitted in the following ways: • E-Gov Web site: https:// www.regulations.gov. This Web site allows the public to enter comments on any Federal Register notice issued by any agency. Follow the instructions for submitting comments. • Fax: 1–202–493–2251. • Mail: Docket Management System: U.S. Department of Transportation, Docket Operations, M–30, Room W12– 140, 1200 New Jersey Avenue, SE., Washington, DC 20590–0001. • Hand Delivery: DOT Docket Management System, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue, SE., Washington, DC 20590–0001 between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. Instructions: Identify the docket number, PHMSA–2007–28993, at the mstockstill on PROD1PC66 with NOTICES ADDRESSES: VerDate Aug<31>2005 18:25 Sep 05, 2007 Jkt 211001 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 https:// www.regulations.gov. FOR FURTHER INFORMATION CONTACT: Barbara Betsock at (202) 366–4361, or by e-mail at barbara.betsock@dot.gov. The Pipeline Inspection, Protection, Enforcement, and Safety Act of 2006 directs PHMSA to review the internal corrosion regulations in subpart H of 49 CFR part 195 to determine if they are adequate to ensure adequate protection of the public and environment and to report to Congress on the results of the review. As an initial step in the review, PHMSA consulted the THLPSSC at its meeting on July 24, 2007. The briefing paper prepared for the committee members contains preliminary data on risk history as well as questions relating to the internal corrosion regulations. This briefing paper is posted on PHMSA’s pipeline Web site (https:// ops.dot.gov) and has been placed in the docket. At the meeting, PHMSA officials committed to gathering additional data responding to questions posed by the committee members. PHMSA has updated the data and included data responsive to the committee members. This data is also posted on the pipeline Web site and contained in the docket. PHMSA requests comments on the adequacy of the internal corrosion regulations and answers to the questions posed in the briefing paper. PHMSA will use these comments in its review of the internal corrosion regulations. SUPPLEMENTARY INFORMATION: SUMMARY: This notice announces the availability of materials, including a briefing paper prepared for PHMSA’s Technical Hazardous Liquid Pipeline Safety Standards Committee (THLPSSC) and data on risks posed by internal corrosion on hazardous liquid pipelines. PHMSA is preparing a report to Congress on the adequacy of the internal corrosion regulations for hazardous liquid pipelines. Participants at a meeting of the THLPSSC discussed issues involved in examining the adequacy of the regulations and requested additional data. PHMSA requests public comment on these matters. DATES: 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. Authority: 49 U.S.C. 60102, 60115, 60117: Sec. 22, Pub. L. 109–468, 120 Stat. 3499. Issued in Washington, DC on August 27, 2007. Jeffrey D. Wiese, Associate Administrator for Pipeline Safety. [FR Doc. E7–17538 Filed 9–5–07; 8:45 am] BILLING CODE 4910–60–P PO 00000 Frm 00092 Fmt 4703 Sfmt 4703 51303 DEPARTMENT OF VETERANS AFFAIRS [OMB Control No. 2900–0675] Proposed Information Collection Activity: Proposed Collection; Comment Request Center for Veterans Enterprise, Department of Veterans Affairs. ACTION: Notice. AGENCY: SUMMARY: The Center for Veterans Enterprise (CVE), Department of Veterans Affairs (VA), is announcing an opportunity for public comment on the proposed collection of certain information by the agency. Under the Paperwork Reduction Act (PRA) of 1995, Federal agencies are required to publish notice in the Federal Register concerning each proposed collection of information, including each proposed extension of a currently approved collection, and allow 60 days for public comment in response to the notice. This notice solicits comments for information needed to identify veteran-owned businesses. Written comments and recommendations on the proposed collection of information should be received on or before November 5, 2007. ADDRESSES: Submit written comments on the collection of information through https://www.Regulations.gov; or Gail Wegner (00VE), Department of Veterans Affairs, 810 Vermont Avenue, NW., Washington, DC 20420 or e-mail: gail.wegner@va.gov. Please refer to ‘‘OMB Control No. 2900–0675’’ in any correspondence. During the comment period, comments may be viewed online through the Federal Docket Management System (FDMS) at https:// www.Regulations.gov. DATES: Gail Wegner at (202) 303–3296 or FAX (202) 254–0238. SUPPLEMENTARY INFORMATION: Under the PRA of 1995 (Pub. L. 104–13; 44 U.S.C. 3501–3521), Federal agencies must obtain approval from the Office of Management and Budget (OMB) for each collection of information they conduct or sponsor. This request for comment is being made pursuant to section 3506(c)(2)(A) of the PRA. With respect to the following collection of information, CVE invites comments on: (1) Whether the proposed collection of information is necessary for the proper performance of CVE’s functions, including whether the information will have practical utility; (2) the accuracy of CVE’s estimate of the burden of the proposed collection of FOR FURTHER INFORMATION CONTACT: E:\FR\FM\06SEN1.SGM 06SEN1

Agencies

[Federal Register Volume 72, Number 172 (Thursday, September 6, 2007)]
[Notices]
[Pages 51301-51303]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 07-4309]


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

DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

[Docket No. PHMSA-2004-19856]


Pipeline Safety: Updated Notification of the Susceptibility to 
Premature Brittle-Like Cracking of Older Plastic Pipe

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

ACTION:  Notice; Issuance of Advisory Bulletin.

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

SUMMARY: PHMSA is issuing this updated advisory bulletin to owners and 
operators of natural gas pipeline distribution systems concerning the 
susceptibility of older plastic pipe to premature brittle-like 
cracking. PHMSA previously issued three advisory bulletins on this 
subject: Two on March 11, 1999 and one on November 26, 2002. This 
advisory bulletin expands on the information provided in the three 
prior bulletins by listing two additional pipe materials with poor 
performance histories relative to brittle-like cracking and by updating 
pipeline owners and operators on the ongoing voluntary efforts to 
collect and analyze data on plastic pipe performance. Owners and 
operators of natural gas pipeline distribution systems are encouraged 
to review the three previous advisory bulletins in their entirety.

FOR FURTHER INFORMATION CONTACT: Richard Sanders at (405) 954-7214, or 
by e-mail at richard.sanders@dot.gov.

SUPPLEMENTARY INFORMATION:

I. National Transportation Safety Board (NTSB) Investigation

    On April 23, 1998, the National Transportation Safety Board (NTSB) 
issued its Special Investigation Report, Brittle-Like Cracking in 
Plastic Pipe for Gas Service, NTSB/SIR-98/01. The report described the 
results of the NTSB's special investigation of polyethylene gas service 
pipe, which addressed three major safety issues: (1) Vulnerability of 
plastic piping to premature failures due to brittle-like cracking; (2) 
adequacy of available guidance relating to the installation and 
protection of plastic piping connections to steel mains; and, (3) 
effectiveness of performance monitoring of plastic pipeline systems to 
detect unacceptable performance in piping systems.
    (1) Vulnerability of plastic piping to premature failures due to 
brittle-like cracking: The NTSB found that failures in polyethylene 
pipe in actual service are frequently brittle-like, slit failures, not 
ductile failures. It concluded the number and similarity of plastic 
pipe accident and non-accident failures indicate past standards used to 
rate the long-term strength of plastic pipe may have overrated the 
strength and resistance to brittle-like cracking for much of the 
plastic pipe manufactured and used for gas service from the 1960s 
through the early 1980s. The NTSB also concluded any potential public 
safety hazards from these failures are likely to be limited to 
locations where stress intensification exists. The NTSB went on to 
state that more durable modern plastic piping materials and better 
strength testing have made the strength ratings of modern plastic 
piping more reliable.
    (2) Adequacy of available guidance relating to the installation and 
protection of plastic piping connections to steel mains: The NTSB 
concluded that gas pipeline operators had insufficient notification of 
the brittle-like failure potential for plastic pipe manufactured and 
used for gas service from the 1960s to the early 1980s. The NTSB also 
concluded this may not have allowed companies to implement adequate 
surveillance and replacement programs for older plastic piping. The 
NTSB explained the Gas Research Institute (GRI) developed a significant 
amount of data on older plastic pipe but the data was published in 
codified terms making it insufficient for use by pipeline system 
operators. The NTSB recommended that manufacturers of resin and pipe, 
industry trade groups and the Federal government do more to alert 
pipeline operators to the role played by stress intensification from 
external forces in the premature failure of plastic pipe due to 
brittle-like cracking.
    (3) Effectiveness of performance monitoring of plastic pipeline 
systems as a way of detecting unacceptable performance in piping 
systems: The NTSB's analysis noted that Federal regulations require 
pipeline operators to have an ongoing program to monitor the 
performance of their pipeline systems. However, the NTSB investigation 
revealed some gas pipeline operators' performance monitoring programs 
did not effectively collect and analyze data to determine the extent of 
possible hazards associated with plastic pipeline systems. The NTSB 
pointed out, ``such a program must be adequate to detect trends as well 
as to identify localized problem areas, and it must be able to relate 
poor performance to specific factors such as plastic piping brands, 
dates of manufacture (or installation dates), and failure conditions.''

[[Page 51302]]

    Copies of this report may be obtained by searching the NTSB Web 
site at www.ntsb.gov.

II. Advisory Bulletins Previously Issued by PHMSA

    The NTSB made several recommendations to PHMSA and to trade 
organizations in its 1998 special investigation report. In response, 
PHMSA issued three advisory bulletins. The first advisory bulletin, 
ADB-99-01, Potential Failure Due to Brittle-Like Cracking of Certain 
Polyethylene Plastic Pipe Manufactured by Century Utility Products Inc, 
was published in the Federal Register (FR) on March 11, 1999 (64 FR 
12211) to advise natural gas pipeline distribution system operators 
that brittle-like cracking may occur on certain polyethylene pipe 
manufactured by Century Utility Products, Inc.
    The second advisory bulletin, ADB-99-02, Potential Failures Due to 
Brittle-Like Cracking of Older Plastic Pipe in Natural Gas Distribution 
Systems, was also published in the Federal Register on March 11, 1999 
(64 FR 12212) to advise natural gas pipeline distribution system 
operators of the potential for brittle-like cracking of plastic pipes 
installed between the 1960s and early 1980s.
    The third advisory bulletin, ADB-02-07, Notification of the 
Susceptibility To Premature Brittle-Like Cracking of Older Plastic 
Pipe, was published in the Federal Register on November 26, 2002 (67 FR 
70806) to reiterate to natural gas pipeline distribution system 
operators the susceptibility of older plastic pipe to premature 
brittle-like cracking. The older polyethylene pipe materials 
specifically identified in ADB-02-07 included, but were not limited to:
     Century Utility Products, Inc. products;
     Low-ductile inner wall ``Aldyl A'' piping manufactured by 
DuPont Company before 1973; and
     Polyethylene gas pipe designated PE 3306.

This third advisory bulletin also listed several environmental, 
installation and service conditions in which plastic piping is used 
that could lead to premature brittle-like cracking failure. PHMSA also 
described six recommended practices for polyethylene gas pipeline 
system operators to aid them with identifying and managing brittle-like 
cracking problems.

III. Plastic Pipe Studies

    Beginning January 25, 2001, the American Gas Association (AGA) 
began to collect data on in-service plastic piping material failures 
with the objective of identifying trends in the performance of these 
materials. The resulting leak survey data, collected from 2001 to 
present, on the county's natural gas distribution systems includes both 
actual failure information and negative reports (reports of no leads) 
submitted voluntarily by participating pipeline operating companies.
    The AGA, PHMSA, and other industry and state organizations continue 
to collect and analyze the data. Unfortunately, the data cannot be 
correlated with the quantities of each plastic pipe material that may 
be in service across the United States. Therefore, the data does not 
assess the failure rates of individual plastic pipe materials on a 
linear basis (i.e. per foot, per mile, etc.). However, the failure data 
reinforces what is historically known about certain older plastic 
piping and components. The data also indicates the susceptibility of 
additional specific materials to brittle-like cracking.

IV. Advisory Bulletin ADB-07-01

    To: Owners and Operators of Natural Gas Pipeline Distribution 
Systems.
    Subject: Updated Notification of the Susceptibility of Older 
Plastic Pipes to Premature Brittle-Like Cracking.
    Advisory: All owners and operators of natural gas distribution 
systems who have installed and operate plastic piping are reminded of 
the phenomenon of brittle-like cracking. Brittle-like cracking refers 
to crack initiation in the pipe wall not immediately resulting in a 
full break followed by stable crack growth at stress levels much lower 
than the stress required for yielding. This results in very tight, 
slit-like, openings and gas leaks. Although significant cracking may 
occur at points of stress concentration and near improperly designed or 
installed fittings, small brittle-like cracks may be difficult to 
detect until a significant amount of gas leaks out of the pipe, and 
potentially migrates into an enclosed space such as a basement. 
Premature brittle-like cracking requires relatively high localized 
stress intensification that may result from geometrical 
discontinuities, excessive bending, improper installation of fittings, 
dents and/or gouges. Because this failure mode exhibits no evidence of 
gross yielding at the failure location, the term brittle-like cracking 
is used. This phenomenon is different from brittle fracture, in which 
the pipe failure causes fragmentation of the pipe.
    All owners and operators of natural gas distribution systems are 
future advised to review the three earlier advisory bulletins on this 
issue. In addition to being available in the Federal Register, these 
advisory bulletins are available in the docket, and on PHMSA's Web site 
at https://phmsa.dot.gov/ under Pipeline Safety Regulations.
    In the first advisory bulletin, ADB-99-01, published on March 11, 
1999 (64 FR 12211), PHMSA advises natural gas distribution system 
operators of the potential for poor resistance to brittle-like cracking 
of certain polyethylene pipe manufactured by Century Utility Products, 
Inc. In the second advisory bulletin, ADB-99-02, published on March 11, 
1999 (64 FR 12212), PHMSA advises natural gas distribution system 
operators of the potential for brittle-like cracking of plastic pipes 
installed between the 1960s and early 1980s.
    In the third advisory bulletin, ADB-02-07, published on November 
26, 2002 (67 FR 70806), PHMSA reiterates to pipeline operators the 
susceptibility of some older plastic pipe to premature brittle-like 
cracking which could substantially reduce the service life of natural 
gas distribution systems and to explain the mission of the Plastic Pipe 
Database Committee (PPDC) ``to develop and maintain a voluntary data 
collection process that supports the analysis of the frequency and 
causes of in-service plastic piping material failures.'' The advisory 
bulletin also lists several environmental, installation and service 
conditions under which plastic piping is used which is used which could 
lead to premature brittle-like cracking failure. PHMSA also describes 
six recommended practices for polyethylene gas pipeline system 
operators to aid them with identifying and managing brittle-like 
cracking problems.
    Lastly, the susceptibility of some polyethylene pipes to brittle-
like cracking is dependent on the resin, pipe processing, and service 
conditions. As noted in ADB-02-07, these older polyethylene pipe 
materials include, but are not limited to:
     Century Utility Products, Inc. products;
     Low-ductile inner wall ``Aldyl A'' piping manufactured by 
DuPont Company before 1973; and
     Polyethylene gas pipe designated PE 3306.

The data now supports adding the following pipe materials to this list:
     Delrin insert tap tees; and,
     Plexco service tee Celcon (polyacetal) caps.

    Authority: 49 U.S.C. chapter 601 and 49 CFR 1.53.


[[Page 51303]]


    Issued in Washington, DC, on August 28, 2007.
Jeffrey D. Wiese,
Associate Administrator for Pipeline Safety.
[FR Doc. 07-4309 Filed 9-5-07; 8:45 am]
BILLING CODE 4910-60-M