water tanks and city supply

[sac32079]

when trying to figure out the pressure rating for a pump and not wanting to exceed 175 psi, do I included the city supply + the psi of my pump rating? I want to give them the most bang for their buck without having pressure relief valves. The tank itself doesn't provide pressure, just for the duration correct? The city water is inadequate @ 20 psi, that is why they want a pump and tank to be installed.

 

[pipesnpumps]

Max height of tane in ft * 0.433 psi/ft = max psi of suction.

Take the maximum suction pressure and add the churn (aka shutoff aka dead-head) pressure of the pump (at zero gpm). The resulting number is the maximum pressure the discharge of the pump will see. See NFPA 20, 5.7.6.1

You can NO LONGER put a relief valve on a pump discharge to protect the piping from over-pressure due to churn.. (5.7.6.2)

Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.

 

[SuperiorFire]

Also, if the tank is elevated above the pump, there will be additional head pressure on the suction side of the pump. Like pipesnpumps said, Height in Ft X 0.433 psi/ft = PSIhead.

Superior Fire Protection Systems
Protectiong Lives and Property since 1986.

Vancouver, British Columbia

http://www.superiorfireprotection.ca