I wonder what the inspectors were doing when they reviewed the info on the hydraulic placard simple math and some common sense would have indicated that something was wrong. The density 0.45 gpm per sq. ft. times the area of operation 2,500 sq. ft. times 1.3 (30% increase for hydraulic inefficiency of tree system) indicates a flow requirement of 1,462.5 rounded up to 1,465 gpm for the system. It appears that the hydraulic placard was based on the design density multiplied by area of operation plus 100 gpm.
What happened to the HPR carriers plan review of the shop drawings and hydraulic calculation or due diligence when taking over the account from another carrier. I hope that the sprinkler contractor doing the annual inspection is following NFPA 25 to the letter and not using any "modified" version of the NFPA 25 inspection form. Just goes to show that you must verify all info given to you. Jim Davidson Davidson Associates 302-994-9500 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Todd Williams - FPDC Sent: Wednesday, October 15, 2008 10:15 AM To: [email protected] Subject: Placard fact check This weeks crisis, so far....... I am working on a plant in MA where they need to add in rack sprinklers. The existing ceiling system is a pipe schedule and the placard at the riser says it can deliver .45/2500 at a flow of 1220 gpm at 52 psi. It seemed light, but I don't jump 'til I crunch the numbers. In actuality, it requires 1558 gpm at 286 psi at the supply. Everybody, including the HPR carrier, has bought into the numbers on the riser. Now the excrement is about to impact the vortex generator. Moral of the story; don't believe everything you read. Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ Sprinklerforum mailing list http://lists.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 http://lists.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)
