One BIG thing that is often overlooked is the Code requirement for Fire Flow. The IFC talks about determining fire flow by an approved method. Jurisdictions vary in the approach they may or may not take in determining fire flow. Appendix B of the IFC is fairly common, however there are other methods used such as ISO or even just providing the required NFPA 13 hose stream allowance. You need to have a conversation with the local FD to find out what they consider their "approved method" of determining fire flow.
Too often the FD just takes what it can get since they aren't involved in conversations early in projects where they could provide input. Some are unaware of the requirement and most A/E's are clueless about the mention of it in the Code. Depending on the conditions, fire flow can require a substantial water supply and delivery system. Also when you're determining water supply remember this, your sprinkler system at 0.20/1500 isn't demanding exactly 300 gpm. I usually factor that value by around 15% because if you look at your calcs the outflow of a typical system is going to be at least 5%-15% greater than the hydraulically remote sprinkler which is the one typically at the design point. So if it was me, for a 0.20/1500 for 60 minutes I'd be looking at around 36,000 gallons (0.20*1500=300gpm, 300gpm*15%=345gpm, 345 gpm+250gpm hose=595gpm, 595gpm*60 minutes duration= 35,700 gallons) includes hose stream but does not consider fire flow. As always, opinions may vary. Craig L. Prahl, CET Fire Protection CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 CH2MHILL Extension 74102 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bobby Gillett Sent: Monday, May 13, 2013 1:19 PM To: [email protected] Subject: Sizing tanks with hydrants? When sizing a water storage tank feeding a fire pump for a new facility with multiple sprinkler systems and fire hydrants, do you have to include any type of allowance for the hydrants? The tank will be the sole source of supply for all (rural area). There will be no hose stations or standpipes, only interior sprinkler systems - OH Group II with monitored alarms. Typically this would be an 18,000 gallon tank minimum (.20x1500x60 mins). I don't see anywhere that requires this, just making sure. Thank you in advance. Bobby Gillett Sr. Project Manager Key Fire Protection, Inc. (731) 424-0130 office (731) 424-9285 fax (731) 267-4853 cell <http://www.keyfireprotection.com> www.keyfireprotection.com _______________________________________________ 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
