Blog Viewer

NTSB Recommends Prohibiting Inside Service Regulators and Requiring Residential Methane Detectors

By John Erickson posted 06-13-2019 10:14 AM

  
In early June, the National Transportation Safety Board (NTSB) issued recommendations to the Pipeline and Hazardous Materials Safety Administration (PHMSA), Gas Technology Institute (GTI), International Code Council (ICC), National Fire Protection Association (NFPA) and others following NTSB’s investigation of an August 10, 2016 gas explosion in Silver Spring, Md. The explosion and fire killed seven residents of the 14-unit apartment building and injured 65 other residents and seven firefighters. NTSB determined that the probable cause of the explosion was the failure of an indoor mercury service regulator with an unconnected vent line that allowed natural gas into the meter room where it accumulated and ignited from an unknown ignition source. Contributing to the accident was the location of the mercury service regulators where leak detection by odor was not readily available. The NTSB concluded that had methane detectors been installed at the apartment complex, an alarm would have alerted residents to a gas release, reducing the potential and consequences of a natural gas explosion.

Therefore, NTSB recommends that, in coordination with NFPA and ICC, GTI should work to develop standards for methane detection systems for all types of residential occupancies in both the IFGC and the National Fuel Gas Code, NFPA 54. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements. Further, NTSB recommends that, in coordination with GTI and ICC, the NFPA revise the National Fuel Gas Code, NFPA 54 to require methane detection systems for all types of residential occupancies with gas service.

The source of the gas was a service regulator vent line that was not properly connected to the regulator vent. NTSB recommended that Washington Gas, the utility serving the apartment complex, include in its service regulator inspection procedures ensuring that the vent line is properly connected. NTSB also recommended that Washington Gas replace all mercury service regulators because the age of these regulators increased the risk of failure. NTSB recommended that PHMSA require that all new service regulators be installed outside occupied structures. Additionally, NTSB recommended that PHMSA require existing interior service regulators to 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.

A copy of the full report is here: For questions on this article, please contact John Erickson of APGA staff by phone at 202-464-2742 or by email at jerickson@apga.org.

Permalink