How Do Emergency Shear Valves Work?

By OPW | Apr 30, 2014

Emergency shear valves are designed to reduce the risk of fire, explosion, personal injury, property damage and environmental contamination at fueling sites around the world. These pieces of equipment are installed on fuel-supply lines beneath dispensers at grade level to minimize hazards associated with collision or fire at the dispenser. If the dispenser is pulled over or dislodged by collision, the top of the valve breaks free at the integral shear groove, activating poppets that shut off the flow of fuel.

10 Plus Ad ArtStandard models of emergency shear valves include single-poppet and double-poppet models. Single-poppet models shut off supply flow, while double-poppet models shut off supply flow as well as prevent release of fuel from the dispenser’s internal piping. In the case of both models, the base of the emergency shear valve must be securely anchored to the concrete dispenser island through a stabilizer bar system within the dispenser sump or pan to ensure proper shearing action. 

In addition to standard models, some updated versions of emergency shear valves include innovative new technology designed to contain fuel leakage at the shear groove and activate the valve to close in the event of a low-impact incident. This is an important consideration because most low-impact incidents go undetected. Without this new technology, these types of incidents could allow fuel to leak into sumps and thereby creating a potentially hazardous situation at the island. 

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