The 10 fps applies only to option 2, not all the options. As long as you meet any ONE of the options, where's the beef?
The objective is to keep loose objects in the main from potentially blocking the sprinkler system. Option 2 assures us that we will remove the loose objects. The other options assure us that the objects will not reach the system since the maximum possible velocity (being less than 10 ft/s) has removed the objects that will move at system demand (which would be the likely lowest velocity). Option 3 allows us to simply open multiple outlets and let it flow whatever flows without having to prove anything. Roland On Mar 30, 2010, at 1:47 PM, <craig.pr...@ch2m.com> <craig.pr...@ch2m.com > wrote: > NFPA 24 says the following: > > NFPA 24: 10.10.2.1.3 The minimum rate of flow shall be not less than > one of the following: > (1) Hydraulically calculated water demand flow rate of the system, > including any hose requirements > (2) Flow necessary to provide a velocity of 10 ft/sec (3.1 m/sec) in > accordance with Table 10.10.2.1.3 > (3) Maximum flow rate available to the system under fire conditions > > > > > > Debate is whether that means that the flow rate dictates the > velocity and it has no absolute requirement or the minimum is 10fps. > > Based on wording in the Appendix it would appear that 10fps is the > desired minimum. > > So for example I have a flow rate of 8000 gpm (fire flow per local > AHJ) and the line size ends up being 24" Vel= 6.74 fps. Is that > acceptable per NFPA 24, 10.10.2.1.3? There are issues with the > distance between source and pump suction and larger pipe equal less > friction loss but also lowers velocities. > > I read it that it can be less than any one of the following with > 10fps being the minimum. Sometimes simpler wording for non-FP > types would make life easier. <sigh> > > Thought, comments, etc????????? > > Craig L. Prahl, CET > Fire Protection Specialist > Mechanical Department > CH2MHILL > Lockwood Greene > 1500 International Drive > PO Box 491, Spartanburg, SC 29304-0491 > Direct - 864.599.4102 > Fax - 864.599.8439 > craig.pr...@ch2m.com > http://www.ch2m.com > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.org > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: supp...@firesprinkler.org > > To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org > (Put the word unsubscribe in the subject field) > _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: supp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
