NTSB Closes Natural Gas Service Line Recommendation
The agency had recommended that PHMSA require that excess flow valves be installed in all new and renewed gas service lines, regardless of a customer's classification, when operating conditions are compatible with readily available valves, and a 2016 final rule has accomplished that.
The National Transportation Safety Board announced last week that a 2001 safety recommendation it made, number SR P-01-002, is now "closed – acceptable action" because of regulatory action taken by the federal Pipeline and Hazardous Materials Safety Administration.
The recommendation came about after a July 1998 natural gas explosion and fire destroyed a new home in Loudoun County, Va., killing one resident and seriously injuring her husband; their two children received minor injuries, according to NTSB, which determined the probable cause of the explosion was corrosion and subsequent overheating and arcing at a splice in one of the conductors of the triplex electrical service line, which, because of inadequate separation between the electrical conductors and the gas service line, led to the failure of the gas service line and the subsequent uncontrolled release of natural gas that accumulated in the basement and was ignited. NTSB found that precipitating the electrical service line failure was damage done to the electrical service line during installation of the gas service line and/or during subsequent excavation of the electrical line.
The agency recommended that PHMSA require that excess flow valves be installed in all new and renewed gas service lines, regardless of a customer's classification, when operating conditions are compatible with readily available valves.
The safety board closed the recommendation on Dec. 5, 2016, in response to an October 2016 final rule by PHMSA that requires installing excess flow valves in multi-residential and commercial applications -- excess flow valves must be installed in new or replaced gas service lines for multi-family residences, including apartment buildings, and small commercial buildings. The rule becomes effective in April 2017. Excess flow valves were already required for new and replaced single-family residence gas service supply lines, according to NTSB.