Code wise I defer to Roland. But there are certainly some variables here at play not addressed. Size of system, air in system and how far above 100. I am a little concerned about 174 psi on a 50,000 sq.ft. HPS with gridded 3" BL's system with a riser ITV, that also feeds the office. The first heads is going to "jump" is it not? The duration over 100 with air in the system is going to be more than momentary. Isn't this the concern, it jumps over the ceiling and becomes useless.
Chris -----Original Message----- From: Ron Greenman <[email protected]> Sender: [email protected] Date: Thu, 20 Jan 2011 13:21:59 To: <[email protected]> Reply-To: [email protected] Subject: Re: Hangers and pressure surges 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) _______________________________________________ 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)
