OK... I have to say that I have learned a thing or two in this thread...but for most of it I keep thinking like a code consultant......somebody tell me I am wrong but....
IBC requires a Class III standpipe for buildings over 30 ft above the lowest level of FD access. Since the building is sprinklered, the Class III requirement is now a Class I requirement due to the IBC exception #1. Now, at 6 stories, the walking surface (floor level) of the 6th floor is almost always less than 75 ft above the lowest level of FD access....a non high rise. Now you go to NFPA 14 5.4 permits manual standpipes for this type of installation...even if in combination with a sprinkler system (See NFPA 14 7.7.3). The only "automatic" requirement in the building code is for Group A occupancies and NFPA 14 only requires it for high rises Bottom line, you can rely on the FD pumper to provide adequate pressure to the top floor....not your fire sprinkler system fire pump. This usually reduces the size of the fire pump considerably and eliminates the issue of having a pump capable of providing min 100 psi at 750-1000 gpm some 65 ft. up while still maintaining system pressure below 175 at the lowest levels at churn. Am I missing something here? I will not say that this logic always works as site conditions can make this a closer call. But an FD pumper pumping at 175 psi should have no trouble overcoming the 65 ft (30 psi) elevation loss and any friction losses with some room to spare. Paul Sincaglia, P.E. _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
