Natural Gas Excess Flow Valve
How Does It Work
An excess flow valve operates similar to electrical circuit breakers that trip when the electricity current exceeds its limit. The excess flow valve is tripped by an excess flow of gas, causing a spring loaded device inside the valve to automatically restrict the flow of gas.
What an EFV will do
The mechanical shut-off device can be installed in the gas pipe running to the gas meter at your property. An EFV is designed to stop the flow of gas if the service line is broken, for example, by an excavation accident. Stopping flow of gas from a broken service line significantly reduce the risk of natural gas fire, explosion, personal injury and or property damage.
What an EFV won’t do
They are not designed to close if a leak occurs beyond the gas meter, on house piping or appliances. EFVs also may not close if the leak on the service line is small. There is also a possibility of closure when additional gas appliances are installed later (example: pool heater, emergency generator, etc.) because the EFV was not sized for the additional flow.