Fire Pump - why the bronze check valve with 3/32 orifice
Fire Pump - why the bronze check valve with 3/32 orifice
(OP)
All the plans I look at for a fire pump system associated with a sprinkler/standpipe system show a "Bronze check valve w/ 3/32" orifice in caliper" in line with the take off coming coming off the discharge line of the pump and going to the fie pump controller.
What is the reason for such a check valve, and what does " 3/32" orifice in caliper" mean ?
Thanks
What is the reason for such a check valve, and what does " 3/32" orifice in caliper" mean ?
Thanks





RE: Fire Pump - why the bronze check valve with 3/32 orifice
RE: Fire Pump - why the bronze check valve with 3/32 orifice
RE: Fire Pump - why the bronze check valve with 3/32 orifice
The check valves are installed in the pressure sensing line at least 5 ft. (1.5 m) apart with a 3/32 inch (2.4 mm) hole drilled in the clapper to serve as a dampening affect on the pressure sensing.
Regarding "3/32" orifice in caliper", it actually reads clapper. The "clapper" is the swinging disc mechanism inside of the check valve. See the last page of the link below:
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You probably should review your detailed equipment drawings so you don't miss something.
RE: Fire Pump - why the bronze check valve with 3/32 orifice
When the fire main pressure dropped due to demand, the CV clapper swing open to allow quick drop in pressure in the pressure sensing line thereby start the fire pump.
RE: Fire Pump - why the bronze check valve with 3/32 orifice
"There shall be two check valves installed in the pressure sensing line at least 5 ft. (1.5 m) apart with a 3/32 inch (2.4 mm) hole
drilled in the clapper to serve as dampening."
"Exception No. 1: If water is clean, ground-face unions with noncorrosive diaphragms drilled with 3/32-in. (2.4 mm) orifices
shall be permitted in place of the check valves."