As noted in the NFPA 13, 2013 edition handbook, "Prior to the 2010 edition, 7.2.3.9 conflicted with the requirement in 7.4.4.1 that combined dry pipe and preaction systems be subdivided as well as contradictory to the requirement in 7.9.2.8.4(5) for separate indicating control valves and check valves for ceiling and in-rack preaction systems, as indicated in figure 7.9.2.8.4. If subdivision is necessary for those systems, there is no reason that it should not be acceptable for dry pipe systems, which operate in similar fashion."
Section 7.2.3.9 was revised in the 2010 edition of NFPA 13 because it was contradictory to 7.4.5.1 Yes, the reason for sub dividing dry pipe (and preaction systems) is/was to speed the water delivery time by not having to exhasut air in the parts of systems not in the direct path of water flow to open sprinklers. All check valves require internal inspection at 5 year intervals per NFPA 25 but the concern noted by the submitter of the change (AFSA rep Roland Huggins) in his statement included in the PI. was that check valves could be frozen closed and not observed, since most inspections are performed in warm months. The installation committee agreed that check valve may still be used but require installation in a heated enclosure to ensure operability. As always, the above is the opinion of the writer and may not be considered as a formal interpretation of NFPA 13, and does not necessarily reflect to views of NFPA or it committees. This opinion should net be relied upon as consultation. Bob Caputo, CFPS President American Fire Sprinkler Association -----Original Message----- From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org> On Behalf Of J H via Sprinklerforum Sent: Tuesday, December 21, 2021 1:34 PM To: sprinklerforum@lists.firesprinkler.org Cc: J H <design.azfire...@gmail.com> Subject: Re: Purpose of Subdividing Dry Systems? Don't be shy, anyone? <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_camp aign=sig-email&utm_content=webmail&utm_term=icon> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_camp aign=sig-email&utm_content=webmail&utm_term=link> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Thu, Dec 16, 2021 at 11:42 AM J H <design.azfire...@gmail.com> wrote: > Hello All, > Is the purpose of subdividing a dry system per NFPA 13, 7.3.9 - > 7.2.3.9.2 > (2013 ed) in order to control system size? Let's say you have a system > that is 1000 gallons and I don't want to be subject to the water > delivery time requirement can I divide the system right down the > middle with a check valve (with the check valve in a heated area and a > hole drilled in clapper) and call it good? If that's not the intention > of the code mentioned what is it for? > > Thanks, > JH > _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.o rg _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
