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:[email protected]] Sent: Tuesday, April 20, 2010 1:51 PM To: [email protected]; [email protected] 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: [email protected] [mailto:[email protected]] On Behalf Of Bob Knight Sent: April 20, 2010 12:30 PM To: [email protected] 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 [email protected] www.firebyknight.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Medina Jr Sent: Tuesday, April 20, 2010 12:41 AM To: [email protected] 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 [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)
