And because I'm so in to "proper" language (see my rant yesterday about design area) and because cecil and I watch each other's back I'm going to mention that everyone keeps saying "small room" when they're talking about "room design method." Small room refers to the s"small room rule" which is a completely different thing. I've noticed after playing on this Forum for years that we all, at one time or another, spend lots of electrons answering questions that weren't asked because the question was confusing.
On Sat, Oct 30, 2010 at 7:11 PM, Sprinkler Academy - C Bilbo <[email protected]> wrote: > > Carrol, > > Hopefully, you caught Ron's reference to 11.3.1.2 and not solely the > requirement for a 20x20 spacing. Specifically, take a look at Ron's inferred > reference to 11.3.1.2 item number 2: > > > 11.3.1.2* Unless the requirements of 11.3.1.3 are met, the minimum required > discharge from each of the four hydraulically most demanding sprinklers shall > be the greater of the following: > (1) In accordance with minimum flow rates indicated in individual listings > (2) Calculated based on delivering a minimum of 0.1 gpm/ft2 (4.1 mm/min) > over the design area in accordance with the provisions of 8.5.2.1 or 8.6.2.1.2 > > Item Number One requires us to examine the listing. The sprinkler listing > for a residential sprinkler likely delivers .05 gpm/sq ft (or just a bit > more) and do not try to "back in" to this density because it is based on a > listed area of 20 x 20 in your case because you are 10 feet off the wall. > This means the listing requires 20 gpm or a little more. > > Item Number Two says to use regular spacing requirements and deliver .10 > gpm/sqft. The question is whether or not the "design area" is the SxL > rule(8.5.2.1) or the "Small Room Rule" (8.6.2.1.2). > > IF (and I mean IF) your room meets the definition of a "small room", then you > may divide the room by the number of sprinklers and deliver .10 gpm/sqft over > THAT "design area". This would meet the requirements of 11.3.1.2, item > number two. In the example you have given to us, you would be able to flow > .10 gpm over the 256 sq ft of "design area" if your room meets the definition > of a small room. The flow from the sprinkler would need to be a minimum of > 25.6 gpm under this method. > > The last step is to compare the flows required by Item One and Item Two. > This is called for in the charging sentence of 11.3.1.2 ("shall be the > greater of the following"). That would mean that your sprinkler must flow > the greater of the listed flow of 20 gpm or the "design area" flow of 25.6 > gpm. Therefore, your sprinkler must flow 25.6 gpm! > > Now go rock on! And have your AHJ call Ron Greenman if he has any further > questions. > > Sincerely, > > A SprinklerGeek named Cecil > > > > > > > >> Date: Sat, 30 Oct 2010 09:49:29 -0700 >> From: [email protected] >> Subject: Re: Residential "Room Design Method"? >> To: [email protected] >> >> That was exactly what I was hoping to hear. Now, hopefully, I can convince >> the >> AHJ of this. I have INCREDIBLE pressure and flow and it seems crazy that I >> can't get 4 heads to flow. >> >> >> Thanks everyone! >> >> Carrol >> >> >> >> >> ________________________________ >> From: Ron Greenman <[email protected]> >> To: [email protected] >> Sent: Sat, October 30, 2010 9:25:04 AM >> Subject: Re: Residential "Room Design Method"? >> >> 2007/11.3.1 >> >> see >> 11.3.1.1 >> and >> 11/.3.1.2 > > > _______________________________________________ > 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)
