You don't have to re-evaluate, provided you don't revise the density. Tony
-----Original Message----- From: sprinklerforum-boun...@firesprinkler.org [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of ParsleyConsulting Sent: April 20, 2010 1:35 PM To: sprinklerforum@firesprinkler.org Subject: Re: Calc Area Brad, I was intrigued by your remarks about having to re-evaluate the minimum length of the remote area parallel to the branch lines if you were to end up with a remote area of a different size than where the standard initially had you start. I can't find anything in my copy of the NFPA-13 handbook, or the Hydaulic Design text book by Pat Brock from Oklahoma State which even remotely suggests this is a requirement. I've never done this, and I want to be sure I haven't missed something critical. I need to be sure I understand what you're saying, because for me the implications are huge for the plans I review on a daily basis for a number of AHJ's. Are you stating that if in order to meet the requirements for a 1,500 square foot remote area I were to end up with a remote area of 1,600 square feet I then have to make an evaluation to make sure that the length of the remote area parallel to the branch lines is at least 1.2 x sqrt of 1,600? In effect, I need at least 48'-0", not the 46'-5" I started with? If that's your position, can you give me some idea of how you determined that such an additional requirement is necessary? I've got to tell you that if that is truly the case, I'm in seriously deep trouble, as I've been doing calculations and plan reviews based on a flawed premise, and that makes me really nervous. Can you give me/us some background on how you came to that conclusion? I'd really appreciate the help. -- PARSLEY CONSULTING Ken Wagoner, SET 760.745.6181 voice 760.745.0537 fax parsleyconsult...@cox.net <mailto:parsleyconsult...@cox.net> e-mail www.ParsleyConsulting.com <http://www.ParsleyConsulting.com> website Brad wrote: > I don't think this is about density at all > > > -----Original Message----- > From: A.P.Silva [mailto:silva...@shaw.ca] > Sent: Tuesday, April 20, 2010 2:13 PM > To: sprinklerforum@firesprinkler.org; bcasterl...@fsc-inc.com > Subject: RE: Calc Area > > If I understand what you are saying, it may not be correct either. If > you use the density corresponding to 1500 SF, then you don't have to > check the length again. If you use the density for 1640 SF, then you are right. > > Tony > > -----Original Message----- > From: sprinklerforum-boun...@firesprinkler.org > [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of Brad > Sent: April 20, 2010 1:02 PM > To: sprinklerforum@firesprinkler.org; b...@firebyknight.com > Subject: RE: Calc Area > > Why average anything--the actual dimensions are right there-- the > thing I am stressing is if you end up with 1640 SF area USED, go back and make sure 49' > does not put you more than half way to ANOTHER head on the line-- the > 1.2 rule is for area USED, not minimum required area. > > -----Original Message----- > From: A.P.Silva [mailto:silva...@shaw.ca] > Sent: Tuesday, April 20, 2010 1:51 PM > To: sprinklerforum@firesprinkler.org; b...@firebyknight.com > Subject: RE: Calc Area > > The critical factor is the length of the design area. Not the number > of heads. For 1500 RA and 1.2 shape factor this is approx. 46.5 feet. > So taking your example, it will be 5 heads per line, whichever side is > the most remote. Your method will work, but maybe not always. Say > substitute 6' for 7' in your example. If the most remote area is the > 8' side, now it is 6 heads on the line. If you use your method and > take 5 heads per line the minimum length of the design area will not be correct. > > Tony > > -----Original Message----- > From: sprinklerforum-boun...@firesprinkler.org > [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of Bob > Knight > Sent: April 20, 2010 12:30 PM > To: sprinklerforum@firesprinkler.org > Subject: RE: Calc Area > > George, > The way I do this is to average the lengths between heads. For > example, you have a branch line with 6 heads. They are spaced 8', > 12', 9', 11', 7', & 10' apart. The average will be 9.5' applying the > 1.2 rule (assuming 1500 > sf) you will have 4.89 (round up to 5) heads per line. If you use the > greatest distance of 12' you end up with only 3.87 (round up to 4) > heads per line. If you chose to use the least dimension of 7' you > will end up with > 6.63 (round up to 7) heads per line. 7 seems like to many and 4 looks > like not enough. This is why I average the distance between heads in > a case such as yours. > > Bob Knight, CET > 1660 Hill Rd > Melba, Idaho 83641 > (208) 318-3057 > (208) 495-2057 fax > b...@firebyknight.com > www.firebyknight.com > > > > -----Original Message----- > From: sprinklerforum-boun...@firesprinkler.org > [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of George > Medina Jr > Sent: Tuesday, April 20, 2010 12:41 AM > To: SprinklerFORUM@firesprinkler.org > Subject: Calc Area > > > If I am calculating a tree type system using the area/design method, > and have several different lengths between sprinklers on a branch > line. Would I use the longest length to determine the amount of > sprinklers on a branch line. I have always used an average (which I've > probably been wrong all these years). > > 1.2vdesign area > S > S= Distance between sprinklers on branch line > > > > 1.2vdesign area > S > S= Distance between sprinklers on branch line > > > > > George Medina Jr. > > > No virus found in this outgoing message. > Checked by AVG - www.avg.com > Version: 9.0.801 / Virus Database: 271.1.1/2820 - Release Date: > 04/19/10 00:31:00 > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.org > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: supp...@firesprinkler.org > > To Unsubscribe, send an email > to:sprinklerforum-requ...@firesprinkler.org > (Put the word unsubscribe in the subject field) > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.org > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: supp...@firesprinkler.org > > To Unsubscribe, send an email > to:sprinklerforum-requ...@firesprinkler.org > (Put the word unsubscribe in the subject field) > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.org > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: supp...@firesprinkler.org > > To Unsubscribe, send an email > to:sprinklerforum-requ...@firesprinkler.org > (Put the word unsubscribe in the subject field) > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.org > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: supp...@firesprinkler.org > > To Unsubscribe, send an email > to:sprinklerforum-requ...@firesprinkler.org > (Put the word unsubscribe in the subject field) > > _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: supp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: supp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
