Ralphy, Your points are all valid. However; I have run into several situations of 3-5 pounds being a critical point, This is after waiving the hose (with approval of AHJ in writing), looping and or gridding, tweaking every single pipe and every single sprinkler. You will find this quite often with the attic requirements added in the 02 edition. So there are times that that amount creates major issues. I know that HW, and other things may help, but I have never seen any get you back to where you need to be. One had to be supplied with a pump.
R/ Matt Matthew J. Willis, CET Automatic Fire Sprinklers Norred Fire Systems L.L.C. 318-387-1134 Voice 318-387-1163 Facsimile [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ralphy Henderson Sent: Thursday, September 24, 2009 12:46 PM To: [email protected]; [email protected] Subject: RE: Inadequate Water You're right but that's not the point. The point is maybe the particular design area is not indicative of the whole building's situation. Maybe the most demanding area could be looped at the branchlines then a supplemental calc performed on the next most demanding area which would establish the norm for the rest of the building. Since most of the time your most demanding area is going to be the one, not neccessarily farthest from the riser but the one with the most sprinklers in your design area or the higher occupancy classification which may not be the case for the typical areas of the building. A secondary calc could establish that but the primary could be calc'd for it's specific characteristics. --- On Thu, 9/24/09, Timothy W Goins <[email protected]> wrote: From: Timothy W Goins <[email protected]> Subject: RE: Inadequate Water To: [email protected] Date: Thursday, September 24, 2009, 4:26 PM "maybe looping a few of the branchlines in the most demanding area would solve things" I always thought that the remote area calcs and design set the standard/minimum for the entire system. No one knows, but GOD and an arsonist, where the actual remote area might be or fire may start/be. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ralphy Henderson Sent: Thursday, September 24, 2009 11:10 AM To: [email protected] Subject: RE: Inadequate Water Isn't an issue of 5 psi really a non issue? I mean, you generally have an AHJ mandated safety factor (or should) of 5-10%, a hose allowance that may or may not be used, plus calculations that are based upon Hazen-Williams which in itself is not as accurate as other methods and provides an additional safety margin. Not only that but there are usually design options as well. Perhaps the remote area could be re-evaluated - maybe there's that head in the closet that really doesn't need to be included in the calcs, maybe looping a few of the branchlines in the most demanding area would solve things, changing BFP to a more friendly friction loss model, did the hydraulics program use the modified equivalent lengths based upon NFPA #13 or were these considerably rounded up by default (I've seen that)? Could changing sprinklers to larger / smaller orifice help, sliding up and down the design density curve to meet actual calculated sq. ft'g (if no reductions are taken) etc.. Even without consideration of the above it would seem that 5 psi is not lawsuit material - at least to me. As long as this is not storage or extra hazard I don't see what the big deal is. -Ralphy _______________________________________________ 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) _______________________________________________ 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)
