Differential ratio of a wet alarm valve
The Loss Prevention Certification Board (LPCB part of BRE Global) sets the standards needed to ensure that fire and security products and services perform effectively. LPCB’s Loss Prevention Standards (LPS) are applied in fire and security sectors around the world.
LPS 1040 - 2.3, Requirements and testing procedures for the LPCB approval and listing of wet alarm valve sets, published by BRE Global in 2014, suggests that the differential ratio of a wet alarm valve is: ‘…the ratio of service pressure to system pressure, measured just before the valve clapper opens to equalise the pressure difference across it, when tested in accordance with the differential ratio test, 1.5.’
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