And if the trapped surge pressure was over 100# but the overall pressure was not you would already have a static exceeding 100 and need the hanger anyways. If you then release a head anywhere in the system you won't have a sudden momentary increase in pressure but an immediate drop towards residual. That is: 1. That I'm understanding the question, or 2. that we're still on planet Earth.
On Thu, Jan 20, 2011 at 12:28 PM, Roland Huggins <[email protected]> wrote: > I don't believe it was the intent to apply the requirement to the possible > build-up of pressure from surges but to the actual available supply. The > definition in 3.3.19 does state exclusive of surges. Combined with the new > expansion of requiring a relief valve on all wet pipe systems instead of > just gridded systems (7.1.2.1 2010 ed), says to me that it's the > characteristics of the water supply that drive the requirement. > > Roland > > > On Jan 20, 2011, at 11:20 AM, Sam Kassab wrote: > >> The pressure relief seems like the best option in this case. >> >> Thanks for the feedback. >> >> Sam Kassab >> TridenT FIRE PROTECTION, INC. >> 13631 Pawnee Rd. , Suite A-1 >> Apple Valley, CA 92308 >> Tel : (760) 961-7222 >> Fax : (866) 501-5942 >> Cell: (805) 801-4676 >> Lic. C-16 935502 >> [email protected] >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Chris >> Cahill >> Sent: Thursday, January 20, 2011 11:12 AM >> To: [email protected] >> Subject: Re: Hangers and pressure surges >> >> The issue is most problematic when the head first pops. So I think the >> AHJ >> has a point. Oh and 9.2.3.4.4.1 seems to actually support the AHJ legally >> where it clearly says static or flowing. >> >> Now if your real static without surge is below 100 you have the option of >> controlling surges instead or changing hangers as I would interpret. >> >> Chris >> -----Original Message----- >> From: "Sam Kassab" <[email protected]> >> Sender: [email protected] >> Date: Thu, 20 Jan 2011 10:46:49 >> To: <[email protected]> >> Reply-To: [email protected] >> Subject: Hangers and pressure surges >> >> NFPA requires hangers to be installed on armovers over 12" when operating >> pressure is over 100 PSI. What if normal street pressure is below 100 PSI >> and pressure surges cause a build-up of 100 PSI or more on the system side >> of the check valve? The AHJ's argument is that the system will have over >> 100 PSI when the system first operates, albeit for a brief moment. Is the >> AHJ correct in his interpretation of this requirement? Has anyone ever >> come >> across this question? >> >> >> >> Thanks in advance. >> >> >> >> Sam Kassab >> >> TridenT FIRE PROTECTION, INC. >> >> 13631 Pawnee Rd. , Suite A-1 >> >> Apple Valley, CA 92308 >> >> Tel : (760) 961-7222 >> >> Fax : (866) 501-5942 >> >> Cell: (805) 801-4676 >> >> Lic. C-16 935502 >> >> <mailto:[email protected]> [email protected] >> >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:[email protected] >> (Put the word unsubscribe in the subject field) >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:[email protected] >> (Put the word unsubscribe in the subject field) >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:[email protected] >> (Put the word unsubscribe in the subject field) >> > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > -- Ron Greenman Instructor Fire Protection Engineering Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: AFSA, SFPE, ASCET, NFPA, NFSA, AFAA, ASEE, NIBS, WSAFM, WFC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
