If you're assuming that the water supply is for both hydrants and building system, then yes. A four story standpipe is usually manual, hence my question about where the FD is going to get their water. Water supplies have to meet either the standpipe or sprinkler demand, whichever is greater so if the only place for the FD to get water is from this tank, then it has to meet the SP flow rate as you allude to, for 30 minutes. And then the OH sprinkler demand for 60 or 90 minutes, whichever applies but you would have to include HSA of 250 GPM in that, assuming both hydrants and system supplied by this tank. Figure out which is the larger of the two numbers and that's the capacity. But if there is adequate independent supply for the fire department to take suction from the hydrants, then it isn't required to be considered in either the standpipe duration or the hose stream allowance.
Steve Leyton Protection Design & Consulting San Diego, CA -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Thom McMahon Sent: Thursday, April 08, 2010 2:36 PM To: [email protected] Subject: RE: Water Supply Excuse me but isn't the standpipe demand required to be met? 500Gpm for the first, 250Gpm for each additional? I would think that you would size the storage for 60-90 min. of whichever is greater just like a combination stand pipe sprinkler supply. Let's assume 3 required stairwells 500+250+250 = 1000Gpm. X 60-90 = 60,000 to 90,000 Gallons of storage. I think this started with Tony saying it was OH I, so figure .15/1500 or .15/3000 = 13,500Gpm to 27,000Gpm for 60 min. x1.5 for 90 min. Standpipe demand is still more, size standpipe demand in this example. Even if it's only one standpipe at 500Gpm, that still more than the 450Gpm the sprinkler system will require for 3000 SF. (If you overflow the sprinklers by more than 10% they may become the more demanding.) Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of A.P.Silva Sent: Sunday, May 09, 2010 1:58 PM To: [email protected] Subject: RE: Water Supply It is a 4 storey sprinklered building with a standpipe as per NFPA 14. The standpipe is manual with the FD pumping into the standpipe system. That is why I thought to size the tank for additional 250 gpm, so FD will have enough. 13, 2007 table 11.2.3.1.1 seems to indicate 60 to 90 minutes for hose allowances also. Is that how you would read? Tony _______________________________________________ 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) __________ Information from ESET NOD32 Antivirus, version of virus signature database 4946 (20100315) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __________ Information from ESET NOD32 Antivirus, version of virus signature database 4946 (20100315) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com _______________________________________________ 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)
