I don't think the committee was trying to aid contractors in doing it fast, as much as acknowledging that it's a common practice and trying to mitigate the risk it can add if there isn't a check valve and they manually shut all the valves. The only real added safety of a check valve in a single story building is holding water in the system allowing some to spray out until the stored pressure is lost in the case of a water supply failure. But if it doesn't set off an alarm, which I would imagine in many cases it won't, it's not doing all that much for you. One has to keep in mind that NFPA 13 is the minimum, and it and it's sister NFPA 25 do a great deal to emphasize protecting the water supply valves, and if the water main fails, usually someone notices the loss of domestic water or the water coming up through the parking lot. I'd rather see owners spend the cost of an alarm valve on better ITM personally.
Mike Morey, CFPS, SET Planner Scheduler/Designer BMWC Constructors, Inc. 1740 W. Michigan St, Indianapolis, IN 46222 O: 317.651.0596 | C: 317.586.8111 [email protected] | www.bmwc.com ________________________________________ From: Sprinklerforum <[email protected]> on behalf of [email protected] <[email protected]> Sent: Thursday, January 22, 2015 10:17 AM To: [email protected] Subject: RE: Why are check valves required on each system in buildings over 2 stories but not in multisystem 1 story buildings Thank you all for the responses. The general consensus then would be to save time when draining a common supply pipe by locking in the water with a check valve rather than closing all the system control valves. Other points brought up are to prevent potential pressure fluctuations as well as accidentally leaving a system control valve closed. Although they all have merit, we can generally address the pressure fluctuations via the flow switch time delay setting and most control valves are electronically monitored in their correct position. Based on this, the only one of those reasons that makes sense to me as to why it is required for multistory buildings versus multisystem single story buildings would be the "drain time of common piping". I think we can all agree someone running up and down stairs would take longer than stepping a couple feet to the side. But was the intent of NFPA to save a contractors time? Based on some of the other things added to the book over the years, I don't think they are concerned with a contractors time and money. I would guess there would have to be some life safety aspect for requiring the check valves. Which brought about my original question, I do not see the how excluding the check valves in single story multisystem buildings is more safe, when they appear to be required for a specific life safety reason in a multistory building. FM Global 2-0 dated January 2014 section 2.6.3 states "Install at least one check valve for each sprinkler system. Providing an alarm check valve, dry-pipe valve, preaction valve or deluge valve will meet the intent of this recommendation." From my understanding of this requirement, they have taken the stance that check valves should be in all systems regardless of building shape/size. Although, I originally proposed this being based on NFPA 13, FM has a vested interest in loss of life and property via dollars out of their pocket. I am wondering why that doesn't appear to be the same concern from NFPA. If anyone has any further commentary I look forward to reading it. Thank you all for you time and input. Thanks, Sean -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of Morey, Mike Sent: Wednesday, January 21, 2015 5:36 PM To: [email protected] Subject: Re: Why are check valves required on each system in buildings over 2 stories but not in multisystem 1 story buildings I believe the handbook explanatory material for at least one of those sections points out that it requires the check valves on multistory buildings to prevent the need to shutdown every floor individually to expedite draining, which adds an additional failure point (control valve left shut). > On Jan 21, 2015, at 11:42 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 _______________________________________________ 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
