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 [email protected] http://www.ch2m.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)
