Makes perfect sense to me! But, BUT what do I do when I look to NFPA to give me some fire power to help with convincing my plan reviewer and "they" come back with the response that small rooms are NOT allowed to be considered in residential applications? I guess I'm assuming that when the sprinkler head's manufacturer's cut sheet states " a minimum discharge of 0.1 GPM/sq. ft. over the "design area" comprised of the four most hydraulically demanding sprinklers for actual coverage areas protected by the four sprinklers.", that "actual" means ACTUAL. Yes, my head is 10 feet off of two walls, but my flow table on my LFII cut sheet tells me that I can and that I'm gonna hit that back wall as long as I have the flow and pressure to back it up. But my actual coverage area is NOT 400 sq. ft.! Not even close.
It doesn't help my situation either when in the Tyco white paper on "Residental Sprinklers Used in NFPA 13, 2002 Applications", the author makes NO reference at all to 8.6.2.1.2. He only cites the S x L rule for determining coverage areas. (big sigh...) Carrol Glimstad Sierra Fire Design ________________________________ From: Roland Huggins <[email protected]> To: [email protected] Sent: Tue, November 2, 2010 8:33:30 AM Subject: Re: Residential "Room Design Method"? the reason it should stay in section 8.6 is because it is the hybrid part of the residential design whereby the 0.1 must also be checked (and that part is being treated like a spray sprinkler). Seems a little history lesson is warranted regarding WHY the 0.1 was added. Long,long ago ok only about 10 yrs starting with TIA 99-1. If you remember back when there was no minimum density on residential sprinklers and effective densities were down around 0.03 gpm/sf, FM did some testing and had some of the test fail miserable. This lead to two primary changes. One was that the foam in the fire test was standardized for heat release rate and the dual discharge requirement of 0.1 gpm/sf and the listing criteria was born. The reason for the 0.1 was not due to the failure of the test (since that was fixed by the changes to the fire test standard). It was due to the realization that the residential sprinkler had been made acceptable for high rise buildings (residential of course) BUT THE FIRE TEST HAD A MAXIMUM DURATION OF 10 MINUTES. Since then, the duration has been extended (to 30 minutes I believe) but at the time that posed a problem. Enter the old faithful light hazard density to rescue the day. This sprinkler was now being designed for both the listing residential criteria (typically close to 0.05) and the good ole 0.1 following the SxL rule. Since the 0.1 was being evaluated like a spray sprinkler, why would it not be reasonable and prudent to apply not just the SxL rule but all spray sprinkler spacing rules? It was reasonable and prudent so it became criteria. Roland On Nov 1, 2010, at 5:13 PM, Ben Young wrote: > That makes no sense. How did the committee allow a reference to SSU/P > spacing criteria under residential sprinkler design. It just makes so > little sense. I was thinking about it as I was driving home... If this is > truly the intent of the code (to average the spacing of residential heads in > small rooms) the correct (in my opinion) IE, non-confusing way to do this > would be to put the same language in the Chapter 8 section about residential > sprinklers or pull 8.6.2.1.2 back into 8.5 or anything other than > referencing residential design methods from SSU/P spacing rules. > > I can't be the only person who thinks that doesn't make a lot of sense, can > I? > > I'm also shocked that I never noticed this before. Believe me, I checked > the 2010 edition, thinking maybe it was a mistake that got rectified, etc. > So I guess part of this is sour grapes too. > > Benjamin Young > _______________________________________________ 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)
