1) Does the 1' wide soffit surround the room? I'm assuming not, because you said it is adjacent. If it did, you could consider the higher part a ceiling pocket and use the 4"-6" pressures. If it is along one wall, then you will need to use the 6"-12" pressures.
2) The handbook uses the term "contiguous" to explain "adjacent" used in 11.3.1.1. >From the handbook explanation: "Unlike the four-sprinkler design basis of NFPA 13R, the four-sprinkler design area in NFPA 13 must be determined without regard to compartment boundaries. The NFPA 13 residential design area consists of the four contiguous sprinklers that together produce the greatest demand, even if they are located in four individual adjacent compartments." "Contiguous" means touching, or in the case of a sprinkler system this pretty much would translate to along the same branch line, main, etc. So, if you have a room with four sprinkler heads, and two are on one branch line that has only those two, while the other two are on another branch line that also has two more heads in different rooms on it, your design area would be the four heads on one branch line, even though there's two others in the room with four heads. Calcing 4 heads on one line will garner greater friction loss and thus higher flows from the heads closer to the main than you would get flowing two lines with two heads. Thus you would be representing the more demanding area. James Litvak Layout Technician VSC Fire and Security Co., Inc. Charlotte Division (704) 805-9764 -----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of John Denhardt Sent: Tuesday, December 23, 2014 8:41 AM To: <[email protected]> Subject: Re: residential calcs #2 - ignore the walls. Most hydraulically demanding 4 sprinklers. Do not forget the .10 verification requirement. This requirement is missed many times. The only case when the walls apply is when the room design method is utilized. John Sent from my iPhone > On Dec 23, 2014, at 8:10 AM, "Todd - Work" <[email protected]> wrote: > > Greg, > > If I were doing the design, I would use the 6-12 criteria. I believe that the > additional water requirement is due to the delay in activation due to the > increased deflector distance (or so I was told). I think you would have the > same situation in that case. > > For #2, the section in 13 requires that the "hydraulically most remote 4 > sprinklers" be calculated. I would make sure your design meets that criteria. > > Todd G Williams, PE > Fire Protection Design/Consulting > Stonington, CT > www.fpdc.com > 860-535-2080 (ofc) > >> On Dec 22, 2014, at 8:12 PM, Greg McGahan <[email protected]> wrote: >> >> Help please.... >> >> Situation in a NFPA 13 hotel...: >> >> There is a 1'-0" wide soffit by 4" deep adjacent to a restroom wall. >> If I place res sidewall 4" under soffit the deflector would then be >> 8" below the higher ceiling past the 1'-0" soffit. >> >> Although I am very conservative with calcs in general - this one >> hurts the pipe sizes bigtime so I am asking if my conservative >> approach is technically correct or overkill: >> >> Question #1 - Do I have to calculate the head for the 6"-12" distance >> below the ceiling or can I use the 4"-6" range? >> >> >> Question #2 - When you do a 4 head Res calc in a 13 building, do you >> define "adjacent" by linear distance or do you purposely go for the >> sidewall in the next room even if it is further away in order to be >> conservative? IW - the nearest pendent in the next room is 4' away, >> going the other direction, the sidewall in the next room is 10' >> away.V's are sidewalls and + are pendents....thats as close as I can get at >> this hour. >> >> I I I V I >> V >> I I I I >> I + I + I + I >> + >> I I I I >> >> >> Greg McGahan >> Living Water Fire Protection, LLC <http://www.livingwaterfp.com> >> 1160 McKenzie Road >> Cantonment, FL 32533 >> 850-937-1850 >> fax 850-937-1852 >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprink >> ler.org > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl > er.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
