In my opinion, the NFPA 13 hose stream demand must be added in order to comply with 903.3.5.2. The writers of this section intentionally added hose stream demand to Section 903 in order to distinguish a high-rise building water supply from the typical tank-fed sprinkler system where no hose stream demand is accommodated (NFPA 13 11.1.5.1, 12.8.1). The standpipes, and the NFPA 14 references, are located in Section 905 where there is no corresponding high-rise supplementary water supply. I think this is the answer if you are the IBC AHJ. If the IFC AHJ wants 250 gpm hose streams when a seismic event disrupts the public water supply, then your local code should be amended to state this.
Bill Brooks William N. Brooks, P.E. Brooks Fire Protection Engineering Inc. 372 Wilett Drive Severna Park, MD 21146 410-544-3620 Phone 410-544-3032 FAX 412-400-6528 Cell -------- Original Message -------- Subject: Hi Rise Secondary Source ... again From: Dave <[email protected]> Date: Thu, December 11, 2008 1:35 pm To: [email protected] Greetings all.. I know I brought up this general topic once before but bear with me on it again. IBC-2006 Section 903.3.5.2 is the requirement for secondary on-site water supply in high rise buildings. Presuming we have an eligible building it comes down to sizing the storage tank or vessel. Code says 30 minutes of sprinkler demand - no problem on that part. It gets muddy at 'including hose stream allowance' -- here's my dilemma. This is a high rise building and it also requires a standpipe to NFPA 14. Many times this means a combination riser for sprinkler and standpipe. Now NFPA 14 tells us that when designing such combinations we do not apply the hose stream allowances of NFPA 13 since 14 is the hose stream standard when it comes to a standpipe system - still with me ?? How do I use a hose stream allowance for tank sizing when Im told not to apply hose stream allowances in the overall design and in reality the FD will be hooking up 2 1/2" hoses to the hose valves and pulling +200 GPM for hoselines. Do we calculate the 250 GPM as the 'hose stream allowance'? If we use the 100 GPM hose stream in NFPA 13 in spite of all this then we will be flowing +200 and having only designed for 100 GPM we will no longer have the 30 minutes of sprinkler duration in a common riser system. What say everyone else - I'm totally up in the air and need something to go with. Dave P. AHJ in NJ _______________________________________________ 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)
