Excess Flow Release Valve

An excess flow valve is a self-regulating safety device installed in a gas service line to automatically latch off the flow of gas / liquid in the event of a significant break, puncture, or severance in the line. Their primary function is to automatically stop the excessive flow of the tank’s liquid or gas contents in the event of a flow line rupture or system failure. Whenever there is a fault in a line like leakage or failure, EFCV designed to shut off the supply of the gas. When the liquid or vapor passing through it exceeds a prescribed flow rate, EFCV shuts down the gas supply. EFCV are also known as velocity check Valve, emergency shutdown device, seismic valve, surge preventer, and line rupture valve.

Why Excess Flow Valve Is Required ?

These valves are used to prevent disasters which can occure in case of rupture of pipeline/ Flexible hoses in working conditions. Excess Flow Check Valve is used to secure damage which can be caused due to large leaks and breaks in a pipeline.

These valves are recommended by several authorities/ standards like OISD, IS-6044 Part 1 & 2, NFPA58, PNGRB, & PESO etc.

How does an excess flow valve function?

Excess flow valves function similarly to electrical circuit breakers, which trip when the current exceeds a preset limit. An excess gas flow trips the excess flow valve, causing a spring-loaded device inside the valve to automatically restrict gas flow. When the reason of excess flowing is repaired, or the service line pressure is similar in both side of valve is equal, the valve automatically resets or reopens.

Where to be install an EFCV ?

The EFCV is installed in the service line that connects the gas/liquid main. The EFCV is installed as close to the gas/ liquid main as possible in most cases. To accommodate interference from other buried structures, the location may need to be installed further away from the gas /liquid main in some cases. These valves also recommended in some cases in line before Pressure gauge, drainage valve etc.