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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 [www.gpo.gov]
[FR Doc No: 2024-26725]

[[Page 90827]]

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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 [email protected].

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), https://www.pipeline-conference.com/abstracts/pipeline-hard-spots-how-hard-hard; see also Rosen Group, Presentation, ``Hard Spot Assessment & 
Integrity Analyses,'' slide 6 (Dec. 13, 2022), https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1050_Hard_Spot_Assessment_-_Integrity_Analysis.pdf (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.'' 
3 4 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 HV10--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 HV10).''
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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), https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1020_PRCI_Efforts_on_Hard_Spots_Dec_2022.pdf.
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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), https://primis-meetings.phmsa.dot.gov/archive/MtgHome.mtg@mtg=161.html; 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), 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.
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     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.
     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.
     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.
     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.
     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), https://www.ntsb.gov/investigations/AccidentReports/Reports/PIR22002.pdf.
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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 https://primis-meetings.phmsa.dot.gov/archive/MtgHome.mtg@mtg=161.html.
    \9\ Rosen Group, Presentation, ``Hard Spot Assessment & 
Integrity Analyses'' (Dec. 13, 2022), https://primis-meetings.phmsa.dot.gov/archive/Day_1_AM_1050_Hard_Spot_Assessment_-_Integrity_Analysis.pdf.
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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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