Thanks Bob, I kept digging, found this verbiage in 1999 NFPA 13, 7-4.1.5.3 Located in the Rack Storage Section. It was also applicable for areas that are highly susceptible to water damage.
"Where preaction systems are used, preaction systems shall be treated as dry pipe systems. Exception: This requirement shall not apply where it can be demonstrated that the detection system that activates the preaction system causes water to be discharged from sprinklers as quickly as the discharge from a wet pipe system." This was new for 1999. So that answers two questions, this was not in force in 1982 and what's there now doesn't have a snowball's chance of working correctly. I can duplicate the original design if I calc it using C-120 for a wet system, if you use C-100 for black steel, dry system as it actually exists, the system is non-functional. NFPA 13, 2010 has removed this statement from all areas within where it used to reside. Oh the fun of it all. Craig L. Prahl, CET Fire Protection Group Lead CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29303 Direct - 864.599.4102 Fax - 864.599.8439 CH2MHILL Extension 74102 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bob Sent: Monday, March 31, 2014 4:22 PM To: [email protected] Subject: RE: Single interlock PA equal to Wet 2002 ed, 12.2.3.2.2.5 (B) Thank You, Bob Knight, CET III 208-318-3057 www.Firebyknight.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Monday, March 31, 2014 2:03 PM To: [email protected] Subject: Single interlock PA equal to Wet At some point in time I thought I had seen a blurb in NFPA 13 which stated that for some certain design conditions a single interlock preaction system was considered the same as a wet pipe system. The rationale behind the premise being that the system piping would be charged prior to activation of sprinklers. Trying to look for a similar statement in NFPA 13 2010, and not just finding it. Anyone recall this in prior or the 2010 edition? Craig L. Prahl, CET Fire Protection Group Lead CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29303 Direct - 864.599.4102 Fax - 864.599.8439 CH2MHILL Extension 74102 [email protected] _______________________________________________ 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 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
