
[Federal Register: September 25, 2008 (Volume 73, Number 187)]
[Notices]               
[Page 55593-55594]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25se08-107]                         

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DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

[Docket ID PHMSA-2008-0255]

 
Pipeline Safety: Workshop on Anomaly Assessment and Repair

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

ACTION: Notice of Workshop.

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SUMMARY: Recent observations by PHMSA indicate possible inconsistencies 
in how natural gas transmission pipeline operators assess and repair 
anomalies, such as corrosion defects, and apply the results of 
calculations to their decision making for further action. Special 
permits granted by PHMSA over the past two years prescribe specific 
assessment and repair procedures for pipelines operating under a class 
location change and maximum allowable operating pressure special 
permit. Moreover, recent research indicating that existing methods of 
predicting the remaining strength of corroded pipe could provide non-
conservative results (i.e., the pipe will fail at a pressure lower than 
that predicted) in some circumstances. Non-conservative results could 
be obtained even when the dimensions of pipeline anomalies are known 
with precision.
    PHMSA is sponsoring a Workshop on Assessment and Repair of 
Anomalies in Pipelines to allow stakeholders of the pipeline safety 
community to learn about and discuss these research results, current 
evaluation practices, and methods to assure pipeline safety. The 
discussion of current evaluation practices and methods to assure 
pipeline safety should include: A review of safety factors used to 
evaluate anomalies when assessing in-line tool and excavation results, 
review of how outside forces and overpressure may effect anomaly 
stresses, how ILI tool accuracy is applied to anomaly evaluation, and 
how anomaly growth rates in assessments are considered.

DATES: The workshop will be held on October 22, 2008. Name badge pick-
up and on-site registration will be available starting at 7:30 a.m. 
with the agenda taking place from 8 a.m. until approximately 5 p.m. 
Refer to the meeting Web site for updated agenda and times: http://
primis.phmsa.dot.gov/meetings/Mtg55.mtg. Please note that the workshop 
will not be Webcast. However, presentations will be available on the 
meeting Web site within 30 days following the workshop.

ADDRESSES: The workshop will be held at the Gaylord National Resort and 
Convention Center, 201 Waterfront Street, National Harbor, MD 20745. 
Hotel reservations under the ``United States Department of 
Transportation 2'' room block for the night of October 21, 
2008, can be made at 1-301-965-2000. A daily rate of $233 is available. 
The meeting room will be posted at the hotel on the days of the 
workshop.

FOR FURTHER INFORMATION CONTACT: Max Kieba at 202-493-0595, or by e-
mail at max.kieba@dot.gov.

SUPPLEMENTARY INFORMATION:
    Registration: Members of the public may attend this free workshop. 
To help assure that adequate space is provided, all attendees are 
encouraged to register for the workshop at http://primis.phmsa.dot.gov/
meetings/Mtg55.mtg. Hotel reservations must be made by contacting the 
hotel directly.
    Comments: Members of the public may also submit written comments, 
either before or after the workshop. Comments should reference Docket 
ID PHMSA-2008-0255. Comments may be submitted in the following ways:
     E-Gov Web Site: http://www.regulations.gov. This 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, 1200 New Jersey Avenue, SE., Room W12-140, Washington, 
DC 20590.
     Hand Delivery: Dot Docket Management System, Room W12-140, 
on the ground floor of the West Building, 1200 New Jersey Avenue, SE., 
Washington, DC between 9 a.m. and 5 p.m., Monday through Friday, except 
Federal holidays.
    Instructions: Identify the Docket ID at the beginning of your 
comments. If you submit your comments by mail, submit two copies. If 
you wish to receive confirmation that PHMSA has received your comments, 
include a self-addressed stamped postcard. Internet users may submit 
comments at http://www.regulations.gov.

    Note: Comments will be posted without changes or edits to http:/
/www.regulations.gov including any personal information provided. 
Please see the Privacy Act heading in the Regulatory Analyses and 
Notices section of the Supplementary Information for additional 
information.

    Privacy Act Statement: Anyone may search the electronic form of all 
comments received for any of our dockets. You may review DOT's complete 
Privacy Act Statement in the Federal Register published April 11, 2000 
(65 FR 19477).
    Information on Services for Individuals with Disabilities: For 
information on facilities or services for individuals with 
disabilities, or to request special assistance at the meeting, please 
contact Max Kieba by October 15, 2008.
    Issue Description: The current regulations contained in 49 CFR 
192.485 and 192.713, allows latitude in methods used for assessing and 
remediating pipe with corrosion anomalies to restore the serviceability 
of pipe. PHMSA has found a wide variation in operators' interpretation 
of how to meet the requirements of pipeline safety regulations in 
assessing, evaluating, and remediating corrosion anomalies. PHMSA 
emphasizes that, while the workshop will involve issues related to Part 
192, the technical discussions on research and methods are of relevance 
to hazardous liquid pipeline operators. For this reason, PHMSA also 
encourages hazardous liquid pipeline operators to attend the meeting.
    Transmission pipelines often operate at high pressures. Pipeline 
design requirements assure that pipe has

[[Page 55594]]

sufficient strength to contain these high pressures and to provide an 
additional safety margin. Pipeline in-service can become degraded due 
to time independent and time dependent threats. Time dependent threats 
include corrosion and other defects which can grow over time and, if 
allowed to continue unchecked, may reduce the pipe wall thickness to 
the point of failure. Time independent threats include excavation 
damage, which are one-time events that may damage the pipeline's 
protective coating, or the pipe itself (e.g., dent, gouge, crack, or 
puncture). The defects caused by time dependent or independent threats 
can reduce the safety margin for retaining the pipeline operating 
pressure.
    Pipeline operators predominantly use one of three accepted methods 
to calculate the remaining strength of pipelines containing metal loss 
anomalies: (1) B31G, (2) Modified B31G, and (3) RSTRENG. These methods 
consider the length and depth of anomalies (i.e., areas of metal loss) 
and produce estimates of the pressure at which the pipe will fail. 
Pipeline operators are required to use these estimates to (1) determine 
whether pipeline pressure must be reduced to provide an additional 
safety margin, and (2) determine the urgency with which anomalies must 
be investigated, evaluated, and repaired.
    In practice, many anomalies are often identified by inspection of 
the pipeline using in-line inspection (ILI) tools. These tools provide 
estimates of the length and depth of anomalies that are used in 
calculating remaining pipeline strength. The dimensions estimated using 
ILI tools are subject to uncertainty because of variables that affect 
the accuracy in determining wall thickness and length.
    Recent research sponsored by PHMSA and industry, evaluated the 
accuracy of the methods currently used to calculate the remaining 
strength of corroded pipelines. The evaluation used data from 
historical and recent bench tests in which pipe with known defects 
(some with real corrosion defects and some with intentionally machined 
defects) were pressurized to failure. The defect size and pipe 
characteristics were used to calculate a predicted failure pressure 
using each of the analytical methods being evaluated. The failure 
pressure predicted by each method was compared to the empirical failure 
pressure determined during the test to identify if the predicted 
failure pressure was conservative or non-conservative. This work 
involved using the analytical methods to calculate the remaining 
strength of pipe containing defects whose dimensions could be measured 
with a high degree of precision. In some cases, the pipe failed at 
pressures lower than those predicted (i.e., the predicted failure 
pressure was non-conservative). This occurred most often for deep 
anomalies (e.g., >60% wall loss) in high-strength pipe (e.g., grade API 
5L X-52 and above). All of the accepted methods for calculating 
remaining pipe strength were found to produce non-conservative 
estimates of failure pressure in some instances.
    The workshop will allow the review and discussion of appropriate 
repair criteria for evaluating anomalies to meet regulatory code 
requirements for the permanent field repair of imperfections and 
damages. The workshop is also intended to allow representatives of the 
pipeline industry, regulatory agencies, the public, and other 
stakeholders to discuss the implications of research results and the 
potential need for regulatory changes or modification of industry 
standards.

Preliminary Workshop Agenda

    The workshop will include:
    (1) Overview of recent research results,
    (2) Perspective of industry and regulators on the implications of 
the research results, and
    (3) Discussion of issues related to reliable application of methods 
for predicting failure pressure of pipe with metal loss defects, 
including:
    a. Treatment of ILI tool accuracy,
    b. Consideration of anomaly growth rates.
    c. Appropriate repair criteria.
    Refer to the meeting Web site for a more detailed agenda: http://
primis.phmsa.dot.gov/meetings/Mtg55.mtg.
    PHMSA publishes requirements for the assessment and repair of 
anomalies discovered by ILI tools or direct measurement in 49 CFR Part 
192 for gas pipelines and Part 195 for hazardous liquids pipelines. 
PHMSA also publishes other anomaly assessment and repair requirements 
for pipelines under special permit for class location and alternative 
MAOP which vary from and are more stringent than the requirements 
contained in regulations. PHMSA plans to discuss assessment and repair 
requirements including the application of factors of safety, ILI tool 
tolerance, and corrosion growth rates. PHMSA will consider the 
discussion at the workshop and comments submitted to the docket in 
determining whether changes to regulatory requirements for anomaly 
assessment and repair are needed in light of the new research results 
and, if so, what those changes should be.

    Issued in Washington, DC on September 19, 2008.
William H. Gute,
Deputy Associate Administrator for Pipeline Safety.
[FR Doc. E8-22602 Filed 9-24-08; 8:45 am]

BILLING CODE 4910-60-P
