To those in urban seismic areas: When required to provide the onsite secondary water supply, is the pump/tank required to provide 100 psi at the top of a combination standpipe or just sprinkler pressure demand? I have a situation where the city/pump combination can meet the standpipe pressure demands at the top, but the tank/pump doesn't.
I have two projects with new high rise buildings being constructed. Both are campus style pumping arrangements (no underground pipe). One of the projects has an existing pump/tank combination which was not designed to meet 100 psi at the top based on tank alone. The combination pump/city supply does meet the standpipe pressure demand, but not the pump/tank. The other project has a pump/city supply which I am adding a pump/tank to. The new pump is redundancy only. Adding the tank without increasing the pump size will not provide 100 psi at the top. [F] 903.3.5.2 Secondary water supply. A secondary on-site water supply equal to the hydraulically calculated sprinkler demand, including the hose stream requirement, shall be provided for high-rise buildings assigned to Seismic Design Category C, D, E or F as determined by this code. The secondary water supply shall have a duration of not less than 30 minutes as determined by the occupancy hazard classification in accordance with NFPA 13. Exception: Existing buildings. Jack Fairchild _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
