Yesterday the OMB’s Office of Information and Regulatory Affairs (OIRA) announced that it had approved PHMSA’s notice of proposed rulemaking (NPRM) for “Excess Flow Valves In Applications Other Than Single-Family Residences in Gas Distribution Systems”. The advance notice of proposed rulemaking (ANPRM) for this rule was published in November of 2011.
‘Excess flow valves’ (EFV) are intended to automatically shut off the flow of a gas line (in this instance) when there is more than a set flow of gas through the valve. This excess flow typically indicates that there is a break in the line somewhere downstream of the valve, thus shutting off the flow to that break will limit the amount of flammable gas that can accumulate in the building. This would limit the size of a subsequent explosion or even prevent such an explosion from occurring.
This rulemaking was initiated in response to NTSB recommendations dating back to 1996. There were industry concerns expressed in response to the ANPRM that EFVs were inappropriate where there were wide changes in gas flow rate.
I would generally expect this NPRM to be published later this week.