Improve Pipeline Leak Detection and Mitigation

​​​​All pipelines leak. Leak-detection and mitigation tools are essential and can make the difference between a minor incident and a deadly explosion. Pipeline systems equipped with leak-detection systems and automatic shutoff valves, or remote-control valves, can warn operators of an imminent accident and allow for quick mitigation.

The NTSB first identified the need for leak-detection and mitigation methods in natural gas transmission and distribution pipelines nearly 50 years ago, but the Pipeline and Hazardous Materials Safety Administration (PHMSA) has yet to require operators to use these life-saving measures, and many operators won’t act without regulation.

Placing service regulators outside buildings is another mitigation tool. Yet many older homes and multifamily structures still have regulators inside, which can trap accumulating gas and lead to an explosion. Methane detection also helps mitigate consequences by alerting the public to natural gas leaks, thereby minimizing public exposure.

Every day we wait to enhance our mitigation systems is a day we put the public in danger.​

Act Now

​​Regulators should:

  • ​Require all operators of natural gas transmission and distribution pipelines to equip their supervisory control and data acquisition systems with tools to assist in recognizing and ​pinpointing the location of leaks.
  • Require the installation of automatic shutoff valves or remote-control valves in  highconsequence areas and in class 3 and 4 locations.
  • Require all new service regulators be installed outside occupied structures and existing interior service regulators be relocated whenever the gas service line, meter, or regulator is replaced. Multifamily structures should be prioritized over single-family dwellings.
  • Require methane-detection systems in residential occupancies with gas service.​

Industry groups should:

  • Revise the National Fuel Gas Code, National Fire Protection Association 54 to require methanedetection systems for all types of residential occupancies with gas service.
  • Develop additional guidance that identifies steps gas distribution operators can take to safely respond to leaks, fires, explosions, and emergency calls.​

Operators should:

  • ​Equip supervisory control and data-acquisition systems with tools to assist in leak detection.
  • Install remote-closure and automatic-shutoff valves in high-consequence areas and class 3 and 4 locations.
  • Review and update as needed:​​

• incident-reporting practices;

• policies and procedures for responding to leaks, fires, explosions, and emergency calls; and

• ​integrity management programs.​​

Safety Recommendations

Open Recommendations that Represent Critical Safety Priorities

<strong> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-21-002">P-21-2 to PHMSA</a></strong>: Evaluate industry’s implementation of the gas distribution pipeline integrity management requirements and develop updated guidance for improving their effectiveness. The evaluation should specifically consider factors that may increase the likelihood of failure such as age, increase the overall risk (including factors that simultaneously increase the likelihood and consequence of failure), and limit the effectiveness of leak management programs.&#160;&#160; <p></p> <strong> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-19-001">P-19-1 to PHMSA</a></strong>: Require that all new service regulators be installed outside occupied structures.​​<br/><p></p><p> <strong> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-19-002">P-19-2 to PHMSA</a></strong>:&#160;&#160;​​​​Require existing interior service regulators be relocated outside occupied structures whenever the gas service line, meter, or regulator is replaced. In addition, multifamily structures should be prioritized over single-family dwellings.​​<br/></p><p> <strong> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-19-006">P-19-6 to International Code Council</a></strong>: In coordination with the Gas Technology Institute and the National Fire Protection Association, incorporate provisions in the International Fuel Gas Code that requires methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements.​<br/></p><p> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-19-007">P-19-7 to National Fire Protection Association</a>:&#160; In coordination with the Gas Technology Institute and the International Code Council, revise the National Fuel Gas Code, National Fire Protection Association 54 to require methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements.​​<br/></p><p> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-11-010">P-11-10 to PHMSA</a>: Require that all operators of natural gas transmission and distribution pipelines equip their supervisory control and data acquisition systems with tools to assist in recognizing and pinpointing the location of leaks, including line breaks; such tools could include a real-time leak detection system and appropriately spaced flow and pressure transmitters along covered transmission lines.​<br/></p><p> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-11-011">P-11-​11 to PHMSA</a>:&#160;​Amend Title 49 Code of Federal Regulations 192.935(c) to directly require that automatic shutoff valves or remote control valves in high consequence areas and in class 3 and 4 locations be installed and spaced at intervals that consider the factors listed in that regulation.​</p>

​​​Closed Recommendations that Highlight NTSB Successes

<p> <strong> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-21-003">P-21-3&#160;to PHMSA</a></strong>: Assist the Railroad Commission of Texas in conducting the audit recommended in Safety Recommendation P-21-4.<br/></p> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-21-004">P</a><a href="https://data.ntsb.gov/carol-main-public/sr-details/P-21-004" style="background-color: #f2f3f4;">-21-004 to State of Texas Railroad Commission</a>:&#160;​With assistance from the Pipeline and Hazardous Materials Safety Administration, conduct a comprehensive audit of Atmos Energy Corporation’s incident-reporting practices; policies and procedures for responding to leaks, fires, explosions, and emergency calls; and integrity management programs. <div><p></p><p> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-21-011">​P-21-011 to ATMOS Every Corporation</a>:&#160;​Revise policies and procedures for responding to leaks, fires, explosions, and emergency calls to address the challenges caused by wet weather conditions. The revised policies and procedures should include:&#160;</p><ol><li>​​leak investigation methods that are reliable in wet weather;&#160;</li><li>leak investigation procedures that assess all viable gas migration paths;</li><li>criteria for when to shut down or isolate gas distribution systems and pressure test main and service lines; and&#160;</li><li>​an alternate safe response such as evacuation when reliable leak investigations are not possible due to wet weather or other circumstances.​​&#160;</li></ol><p> <a href="https://data.ntsb.gov/carol-main-public/sr-details/P-21-013">P-21-013 to American Gas Association and Gas Piping Technology Committee</a>:&#160;Develop additional guidance that identifies steps gas distribution operators can take to safely respond to leaks, fires, explosions, and emergency calls, considering the limitations due to wet weather conditions, that includes:&#160;</p><p></p><ol><li>​criteria for when to shut down or isolate gas distribution systems, pres&#160;sure test main and service lines, and begin evacuations;&#160;</li><li>leak investigation methods that are reliable in wet weather,&#160;</li><li>require an alternate safe response, such as an evacuation when reliable leak investigations are not possible due to wet weather, and&#160;</li><li>leak investigations that assess all viable gas migration paths, including granular backfill and crawlspaces.​​<br/><br/></li></ol> ​<a href="https://data.ntsb.gov/carol-main-public/sr-details/P-19-008">P-19-08 to Gas Technology Institute<strong></strong>​</a>: In coordination with the National Fire Protection Association and the International Code Council, work to develop standards for methane detection systems for all types of residential occupancies in both the International Fuel Gas Code and the National Fuel Gas Code, National Fire Prot​ection Association 54. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements.​ <div>&#160;<br/></div><div><div style="text-align: right;"><br/></div></div> </div>
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