The Chalwyn SVX hazardous area series of butterfly air intake shutoff valves are ATEX approved for Zone 1, Gas Group IIB, T4 or Zone 21 hazardous area applications. The 12 and 24VDC valves are designed with “fail safe” actuation. The valve is held open when electrical power is supplied to the solenoid. When power is cut off due to the detection of an engine overspeed condition or cut off for any other reason, the valve will close.