The many good reasons for having a check valve per floor has been stated but allow me to ’plain the how it here. Horizontally each riser on the manifold is a system. Vertically all floor were a single systems so 13 did not require a check valve. NFPA 14 for combined standpipe / sprinkler risers required one, the building code required high rises to have a control valve per floor. NFPA 13 did NOT say each floor is a system even in a high rise. In the 2013 edition, without a lot of fanfare, NFPA 13 has indirectly stated that for buildings greater than two stories (with some exceptions) each floor is a system. See section 8.16.1.5.1. I say indirectly because it doesn’t say the floor is a system but it requires all the components that makes the connection to the vertical manifold a system riser. NOTE that the check valve is not part of the system riser components and the aforementioned (seems like that really should be two words) reasons encouraged its' addition.
This issue was actually triggered within NFPA 25 and the effort to clearly identify whether a main drain must be conducted on every floor of a hi-rise. Roland Roland Huggins, PE - VP Engineering American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives Dallas, TX http://www.firesprinkler.org <http://www.firesprinkler.org/> > On Jan 21, 2015, at 8:42 AM, [email protected] wrote: > > Consider NFPA 13 (2013) as the applicable standard. > > Question - Why are check valves required on each sprinklers system riser when > buildings are over 2 stories in height but they are not required on each > system riser when the building is single story (ex: warehouse with multiple > systems on a manifold)? > > Please assume for this question each system will have a DCBFP device between > the city water connection and the building. Also please assume the FDC (with > check valve) is tied directly into the manifold/standpipe downstream of the > DCBFP and prior to any system control valves. > > My code references are as follows: > 3.5.12 System Riser - The aboveground horizontal or vertical pipe between the > water supply and the mains (cross or feed) that contains a control valve > (either directly or within its supply pipe), pressure gauge, drain, and water > flow alarm device. > 8.16.1.5.1 - Multistory buildings exceeding two stories in height shall be > provided with a floor control valve, check valve, main drain valve, and flow > switch for isolation, control, and annunciation of water flow on each floor > level. > 8.17.5.2.2(1) - Each connection from a standpipe that is part of a combined > system to a sprinkler system shall have an individual control valve and check > valve of the same size as the connection. [This is identical to NFPA 14 > (2013) - 6.3.5.1] > > What I do not understand is why check valves would be required on each system > riser when you go vertical, but not horizontal. Any clarity on this > question, specifically "WHY" would be greatly appreciated. > > Thanks, > Sean > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
