Travis got it right. They can not use 4.2 K sprinklers if it OH or higher. Reject!!!!
John John August Denhardt, P.E. Strickland Fire Protection Incorporated 5113 Berwyn Road College Park, Maryland 20740 Office Telephone Number: 301-474-1136 Mobile Telephone Number: 301-343-1457 FIRE SPRINKLERS SAVE LIVES -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Travis Mack Sent: Monday, November 30, 2009 3:18 PM To: [email protected] Subject: Re: Calcs-How much margin Without checking, I thought you could only use small orifice sprinklers in light hazard? Ok, I did check. I think this section says you can only use them in LH: 8.3.4 Small Orifice Sprinklers. 8.3.4.1 For light hazard occupancies not requiring as much water as is discharged by a sprinkler with a nominal K-factor of K-5.6 (80) operating at 7 psi (0.5 bar), sprinklers having a smaller orifice shall be permitted, subject to the following restrictions: (1) The system shall be hydraulically calculated. (2) Sprinklers with nominal K-factors of less than K-5.6 (80) shall be installed only in wet pipe sprinkler systems or in accordance with the limitations of 8.3.4.2 or 8.3.4.3. (3) A listed strainer shall be provided on the supply side of sprinklers with nominal K-factors of less than K-2.8 (40). > I've got a calc I'm reviewing, after all said and done, 3.63 psi margin > between demand and available. Designer used 4.2K heads to get the flow > exactly to the decimal of the required flow. This is an industrial type > project. With a .15 gpm/sf density at 92 sf per head, the flow would be > 13.8 gpm and he's dead on the money. The concern would be that over the > years if there was any change in the water supply or decay of the piping, > that the operation of half the design area would be questionable. > > Would you approve or reject this design? Is this cutting it just a bit > close? > > > > > 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) > -- _______________________________________________ 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) _______________________________________________ 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)
