Notice2024-26725
Pipeline Safety: Identification and Evaluation of Potential Hard Spots-In-Line Inspection Tools and Analysis
Primary source
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Published
November 18, 2024
Issuing agencies
Transportation DepartmentPipeline and Hazardous Materials Safety Administration
Abstract
PHMSA is issuing this advisory bulletin to notify pipeline owners and operators of the importance of evaluating their pipeline facilities for the existence and potential threat of hard spots in the pipe body. That susceptibility comes from the plate and pipe manufacturing and is broader than previously understood; recent data and incident investigations indicate that hard spots could affect multiple pipelines manufactured prior to 1970. Hard spots, if not identified and mitigated, pose a threat to the integrity of the pipeline from interacting threats such as coating degradation, soil chemistry, and/or increased hydrogen exposure, which can result in hydrogen-induced cracking. Pipeline owners and operators should consider expanding their hard spot threat evaluation to all pipe manufactured prior to 1970, regardless of manufacturer; collecting and analyzing data associated with hard spot magnetic flux leakage in-line inspection tools; and following industry best practices when conducting in-line inspection data analysis.
Full Text
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<title>Federal Register, Volume 89 Issue 222 (Monday, November 18, 2024)</title>
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[Federal Register Volume 89, Number 222 (Monday, November 18, 2024)]
[Notices]
[Pages 90827-90829]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-26725]
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DEPARTMENT OF TRANSPORTATION
Pipeline and Hazardous Materials Safety Administration
[Docket No. PHMSA-2024-0176]
Pipeline Safety: Identification and Evaluation of Potential Hard
Spots--In-Line Inspection Tools and Analysis
AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA),
Department of Transportation.
ACTION: Notice; issuance of advisory bulletin.
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SUMMARY: PHMSA is issuing this advisory bulletin to notify pipeline
owners and operators of the importance of evaluating their pipeline
facilities for the existence and potential threat of hard spots in the
pipe body. That susceptibility comes from the plate and pipe
manufacturing and is broader than previously understood; recent data
and incident investigations indicate that hard spots could affect
multiple pipelines manufactured prior to 1970. Hard spots, if not
identified and mitigated, pose a threat to the integrity of the
pipeline from interacting threats such as coating degradation, soil
chemistry, and/or increased hydrogen exposure, which can result in
hydrogen-induced cracking. Pipeline owners and operators should
consider expanding their hard spot threat evaluation to all pipe
manufactured prior to 1970, regardless of manufacturer; collecting and
analyzing data associated with hard spot magnetic flux leakage in-line
inspection tools; and following industry best practices when conducting
in-line inspection data analysis.
FOR FURTHER INFORMATION CONTACT: Max Kieba, Director, Engineering &
Research Division, at 202-420-9169 or <a href="/cdn-cgi/l/email-protection#c489a5bcea8fada1a6a584a0abb0eaa3abb2"><span class="__cf_email__" data-cfemail="561b372e781d3f3334371632392278313920">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
I. Background
The purpose of this advisory bulletin is to notify owners and
operators of gas, hazardous liquid, and carbon dioxide pipelines of the
importance of evaluating their pipeline facilities for the existence
and potential threat of hard spots in the pipe body. A major tenet of
PHMSA's pipeline safety oversight program is that pipeline operators
must know and understand their pipeline systems, and use appropriate
technologies and procedures to address risks to prevent pipeline
failures while considering the inherent limitations of such technology.
PHMSA prescribes factors that must be addressed to mitigate risk and
conducts inspections to ensure adequate measures are carried out
effectively.
A hard spot is a defect that is created at the time the steel
plates are rolled during the pipe manufacturing process. The creation
of hard spots in manufacturing is not attached to the in-service
product. Even where a pipe may have an intended service at the time of
manufacture, the intended service may change after manufacture. A
localized increase in hardness produced during the hot rolling of steel
plates as a result of localized cooling can form a hard spot. Localized
hardening may also occur through the unintentional quenching during the
manufacturing process or by cold work. Although hard spots are more
prevalent in plate-formed pipe, seamless pipe can also be susceptible
to hard spots when poor controls in the manufacturing process result in
material property variations, including hardness.\1\
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\1\ See Jeremy Faissat et al., ``Pipeline Hard Spots: How Hard
is Hard?,'' Pipeline Technology Conf. 2021 (Apr. 1, 2021), <a href="https://www.pipeline-conference.com/abstracts/pipeline-hard-spots-how-hard-hard">https://www.pipeline-conference.com/abstracts/pipeline-hard-spots-how-hard-hard</a>; see also Rosen Group, Presentation, ``Hard Spot Assessment &
Integrity Analyses,'' slide 6 (Dec. 13, 2022), <a href="https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1050_Hard_Spot_Assessment_-_Integrity_Analysis.pdf">https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1050_Hard_Spot_Assessment_-_Integrity_Analysis.pdf</a> (National Tube pipe).
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Hardness can be measured in any condition, at any time, and is
determined by measuring the depth of an indentation made by a
calibrated indentation device. There are three industry standards that
address hardness testing: (1) ASTM E92 Standard Test Methods for
Vickers Hardness of Metallic Materials; (2) ASTM E10-18 Standard Test
Methods for Brinell Hardness of Metallic Materials; and (3) ASTM E18-22
Standard Test Methods for Rockwell Harness of Metallic Materials. Hard
spots found by in-line inspection (ILI) analysis can be verified
through the use of calibrated devices that press a specific tool into
the plate's surface and then measure the resulting width or depth of
the indentation.\2\ American Petroleum Institute (API) Specification 5L
states that ``[a]ny hard spot larger than 50 mm (2.0 in) in any
direction shall be classified as a defect if its hardness exceeds 35
HRC, 345 HV10 or 327 HBW, based upon individual indentations.''
<SUP>3 4</SUP> However, recent improvements in technology have revealed
incidents on hard spots with lower hardness measures.
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\2\ The three hardness units--HRC, HB and HV<INF>10</INF>--can
be converted using a standard conversion table.
\3\ API Specification 5L, ``Specification for Line Pipe,''
section 9.10.6, (46th ed., Apr. 2018) (incorporated by reference
under 49 CFR 192.7 and 195.3).
\4\ 49 CFR 192.3 defines a ``hard spot'' as ``an area on steel
pipe material with a minimum dimension greater than two inches (50.8
mm) in any direction and hardness greater than or equal to Rockwell
35 HRC (Brinell 327 HB or Vickers 345 HV<INF>10</INF>).''
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Hard spots generally form on the surface of pipe and, by
themselves, can be considered a stable threat. Unfortunately, hard
spots can become unstable when the threat is activated by a change in
service conditions such as coating degradation, effects of soil
chemistry, and/or influence of the cathodic protection hydrogen film.
The presence of hydrogen can result in hydrogen-induced cracking due to
hydrogen accumulation at inclusions, impurities, and lattice structure
irregularities in the presence of stress on the steel (e.g., from
operating pressures). Typically, coatings insulate hard spots from
exposure to hydrogen generated by the cathodic protection system, but
coatings can deteriorate over time. Recent Pipeline Research Council
International (PRCI) research indicates that the level of cathodic
protection may also contribute to hydrogen cracking.\5\
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\5\ Zoe H. Shall, Presentation, ``PRCI Efforts on Hard Spots:
Past, Present, and Future,'' slide 15 (Dec. 13, 2022), <a href="https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1020_PRCI_Efforts_on_Hard_Spots_Dec_2022.pdf">https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1020_PRCI_Efforts_on_Hard_Spots_Dec_2022.pdf</a>.
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PHMSA has previously discussed, in public meetings and workshops,
the threat evaluations of pipelines constructed with pipe manufactured
by A.O. Smith Corporation (A.O. Smith) from 1948 through 1952 due to
the pipe's susceptibility to hard spot related hydrogen cracking.\6\ In
the past 20 years, the following five incidents highlight hydrogen-
induced cracking of hard spots. All but one of the incidents occurred
on pipe manufactured by A.O. Smith.
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\6\ Gery Bauman & Mary McDaniel, Presentation, ``Recent Case
Study hard Spts and NTSB Recommendation P-22-3,'' slide 20 (Dec. 13,
2022), <a href="https://primis-meetings.phmsa.dot.gov/archive/MtgHome.mtg@mtg=161.html">https://primis-meetings.phmsa.dot.gov/archive/MtgHome.mtg@mtg=161.html</a>; see generally, PHMSA, ``Class Location
Special Permits: FAQs,'' FAQ 34 (June 16, 2010) (providing that hard
spots are a safety condition that may reduce the toughness of pipe
body), <a href="https://view.officeapps.live.com/op/view.aspx?src=https%3A%2F%2Fwww.phmsa.dot.gov%2Fsites%2Fphmsa.dot.gov%2Ffiles%2Fdocs%2Ftechnical-resources%2Fpipeline%2Fclass-location-special-permits%2F64051%2Ffaqsclass-location-special-permits20180726.docx&wdOrigin=BROWSELINK">https://view.officeapps.live.com/op/view.aspx?src=https%3A%2F%2Fwww.phmsa.dot.gov%2Fsites%2Fphmsa.dot.gov%2Ffiles%2Fdocs%2Ftechnical-resources%2Fpipeline%2Fclass-location-special-permits%2F64051%2Ffaqsclass-location-special-permits20180726.docx&wdOrigin=BROWSELINK</a>.
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<bullet> On July 18, 2013, a 30-inch natural gas pipeline ruptured
in Natchitoches, Louisiana. The pipe was manufactured in 1952 by A.O.
Smith. Evidence suggested the failure was caused by hydrogen-induced
cracking in a hard spot that was previously reinforced with a Type A
sleeve. The leak, in this instance, was repaired with a Type B sleeve.
<bullet> On January 14, 2015, a 30-inch natural gas pipeline
ruptured in
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Brandon, Mississippi. The pipe was manufactured in 1952 by A.O. Smith.
The failure was caused by hydrogen-induced cracking in a hard spot
greater than two inches in length, previously reinforced with a Type A
sleeve. Hardness testing could not be performed with the sleeve in
place.
<bullet> On August 1, 2019, a 30-inch natural gas pipeline ruptured
in Danville, Kentucky. The pipe was manufactured in 1957 by A.O. Smith.
The failure was caused by hydrogen-induced cracking in a hard spot.
Hardness testing by the National Transportation Safety Board (NTSB)
identified the origin hard spot was 5.85 inches by 3 inches, and had
hardness values between 362 and 381 Brinell. Hardness readings extended
through the pipe wall.
<bullet> On February 13, 2022, an 18-inch natural gas pipeline
ruptured in Perry County, Mississippi. The pipe was manufactured in
1950 by A.O. Smith. The failure was caused by hydrogen-induced cracking
in a hard spot. Metallurgical testing found hardness values between 35
to 45 Rockwell, and was measured at approximately 0.6-inch by 2.5-inch.
<bullet> On March 8, 2023, a 30-inch natural gas pipeline ruptured
in Fauquier County, Virginia. The pipe was manufactured in 1957 by
Bethlehem Steel. The failure was caused by hydrogen-induced cracking in
a hard spot. Post incident ILI identified six hard spot features, and
hardness values were confirmed from four features that ranged from 192-
208 Brinell, which was slightly harder than base hardness
(approximately 170 to 180 Brinell). In this instance, the operator did
conduct a re-analysis of its data that resulted in updated results to
identify the presence of additional hard spots.
The NTSB conducted an investigation following the August 1, 2019,
Danville, Kentucky, incident, and made findings and recommendations
regarding identification and evaluation of hard spots.\7\ Specifically,
the NTSB issued recommendation P-22-003 to PHMSA to ``[a]dvise natural
gas transmission pipeline operators of the possible data limitations
associated with hard spot magnetic flux leakage in-line inspection
tools and analyses used in hard spot management programs and reinforce
the need to follow industry best practices when conducting in-line
inspection data analysis.''
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\7\ NTSB, Pipeline Investigation Report PIR-22/02, ``Enbridge
Inc. Natural Gas Transission Pipeline Rupture and Fire, Danville
Kentucky, Aug. 1, 2019'' (Aug. 15, 2022), <a href="https://www.ntsb.gov/investigations/AccidentReports/Reports/PIR22002.pdf">https://www.ntsb.gov/investigations/AccidentReports/Reports/PIR22002.pdf</a>.
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Following the NTSB investigation into the Danville incident, PHMSA
reviewed accident data and information regarding hard spots and the
appropriate methodologies and technologies for detecting hard spots.
PHMSA met with industry and technology companies to gather more
information regarding hard spot management programs; communicate the
results of the data analysis; and discuss appropriate ILI technologies
for different anomalies, including hard spot detection. Additionally,
PHMSA hosted an informational three-day public meeting in December
2022, in Houston, Texas, to discuss topics relevant to the pipeline
industry.\8\ One topic in particular included a discussion of both the
NTSB's findings and hard spot safety concerns. PHMSA presented an
overview of the NTSB's PIR-22/02 report into the Danville incident.
During the December 2022 meeting, PHMSA invited stakeholders to present
information related to hard spot methodologies/technologies used for
detecting hard spots and discussed the circumstances of this incident.
PHMSA has continued to meet with technology companies to review hard
spot studies and hard spot management programs. As a result of the
studies and communications, PHMSA has identified more pipe
manufacturers and pipe manufacture vintages that could have issues with
hard spots. In addition to A.O. Smith pipe, Bethlehem Steel
Corporation, Kaiser Steel Corporation, National Tube Supply,
Consolidated Pipe & Supply, Youngstown Sheet and Tube, United States
Steel, Claymont Steel, and Republic Steel have been identified as
manufacturers with manufacture dates as recent as 1970 whose pipe may
experience hard spots.\9\
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\8\ Information and presentations for this December 2022 public
meeting are available at <a href="https://primis-meetings.phmsa.dot.gov/archive/MtgHome.mtg@mtg=161.html">https://primis-meetings.phmsa.dot.gov/archive/MtgHome.mtg@mtg=161.html</a>.
\9\ Rosen Group, Presentation, ``Hard Spot Assessment &
Integrity Analyses'' (Dec. 13, 2022), <a href="https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1050_Hard_Spot_Assessment_-_Integrity_Analysis.pdf">https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1050_Hard_Spot_Assessment_-_Integrity_Analysis.pdf</a>.
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In addition, new technologies and advancements in ILI have resulted
in the ability to learn more using previously obtained ILI data. For
example, in the August 2019 Danville, Kentucky, hard spot failure, the
NTSB investigation determined that the initial 2011 ILI data analysis
had identified 16 hard spots in the relevant line section yet the 2019
re-analysis of the 2011 data identified 441. The NTSB attributed this
discrepancy in identifications to significant improvements in computer
hardware, software, and data analysis.\10\ PHMSA and researchers have
found that older data can be re-analyzed, and previously unidentified
hard spots can be identified. It is important when analyzing the
possibility of hard spots to verify the capabilities of the tool and
verify the data collected. PHMSA believes that data verification should
not be limited in scope and should include a thorough review of all
relevant data.
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\10\ NTSB, PIR-22/02 at 29.
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PHMSA provides this advisory bulletin to help gas, hazardous
liquid, and carbon dioxide pipeline owners and operators and the public
understand the threat of hard spots and how to better comply with the
existing requirements under federal pipeline safety regulations.
Guidance and advisory bulletins are not substantive rules; are not
meant to bind the public in any way; and do not assign duties, create
legally enforceable rights, or impose new obligations that are not
otherwise contained in those regulations.
II. Advisory Bulletin (ADB-2024-01)
To: Owners and Operators of Gas, Hazardous Liquid, and Carbon
Dioxide Pipeline Systems.
Subject: Identification and Evaluation of Potential Hard Spots--In-
line Inspection Tools and Analysis.
Advisory: PHMSA is issuing this advisory bulletin to advise gas,
hazardous liquid, and carbon dioxide pipeline owners and operators of
new information regarding the potential for the presence of hard spots
in pipelines, and their associated safety and environmental risks of
leaks or ruptures. This advisory alerts operators of advancements in
knowledge of hard spot susceptibility, most notably that what was once
considered to be an issue confined to a single manufacturer (A.O.
Smith) of specific, limited manufacturing years, is now understood to
include potentially other manufacturers and manufacturing years.
Additionally, the presence of hydrogen may result in hydrogen-induced
cracking due to hydrogen accumulation at inclusions, impurities, and
lattice structure irregularities in the presence of stress on the
steel. For pipelines, the stress is typically operational pressure.
Typically, coatings isolate hard spots from exposure to hydrogen
generated by the cathodic protection system, but coatings can and do
deteriorate over time. Recent PRCI research indicates that the level of
cathodic protection and the chemistry of the surrounding soil may
contribute to hydrogen cracking.
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New technologies and advancements in ILI have resulted in the
ability to better identify features associated with hard spots.
Additionally, PHMSA and researchers have found that significant
improvements in computer hardware, software, and data analysis have
enabled the use of older data to be re-analyzed, and previously unknown
features identified. It is important to verify the capabilities of the
tool and verify the data when analyzing for the possibility of hard
spots.
For these reasons, pipeline operators should consider taking the
following actions to ensure pipeline safety:
1. Review all design and construction records to ensure they are
traceable, verifiable, and complete to determine whether enough
information is available to identify the pipe manufacturer, the steel
plate manufacturer, and the date of manufacturing.
2. Review and determine whether or not the types of pipes in the
system are susceptible to hard spots;
3. Review and determine if known integrity issues have been
experienced on those pipelines;
4. Develop and implement an enhanced assessment program to
establish the best approach to material hardness anomaly validations;
5. Re-evaluate existing ILI data to support current feature
identification; and
6. Continue sharing information used to evaluate the identification
of hard spots and the other factors that may contribute to the
destabilization of hard spots in industry and public pipeline technical
meetings and conferences.
Issued in Washington, DC, on November 1, 2024, under authority
delegated in 49 CFR 1.97.
Alan K. Mayberry,
Associate Administrator for Pipeline Safety.
[FR Doc. 2024-26725 Filed 11-15-24; 8:45 am]
BILLING CODE 4910-60-P
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