Title: AV-1 alarm valve.pdf
Same drilling as for B16.5 (Class 150) and B16.42 (Class 250). Same drilling as for BS 4504 Section 3.2 (PN10) and DIN 2532 (PN10). Same drilling as for BS 4504 Section 3.2 (PN16) and DIN 2532 (PN16).Dim. B Bolt Hole DiameterQty. N Number of Bolt HolesTABLE B FLANGE DRILLING SPECIFICATIONSTFP910 Page 4 of 20Operation When the fire protection system is ini- tially pressurized, water flows into the system until the water supply and sys- tem pressure become equalized, and the torsion Spring closes the Water- way Clapper in the Alarm Check Valve. Once the pressures stabilize, the Alarm Check Valve is in service and the cen- trally located groove in the Seat Ring is sealed. Consequently, with the Alarm Check Valve set for service, there is no flow through the alarm port to the alarm devices (i.e., water motor alarm and/or pressure alarm switch).