You will also gain psi dropping to a lower ceiling (2 foot drop will net you that .8 psi loss) And you can reduce your design area with a lower ceiling too, if you meet the requirements in 13.
Bryan A. Dann Dannba Design Services, LLC Fire Sprinkler Designs Office: (740) 363-5878 Cell: (740) 803-0967 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Scott A. Futrell Sent: Thursday, February 07, 2008 9:49 AM To: [email protected] Subject: RE: Arm over Calculations Craig, There isn't a cut and dried answer, and the answer has something to do with your expertise in hydraulic calculations. Adding a five foot armover with an elbow (assuming the tee was already included in the shell calculations), if the spacing is 225 square feet adds 0.8 psi in schedule 40, c=120, 1" pipe, which is not much. However if the available supply was used up in the original calculation then that little bit would be too much. However, adding sprinklers may add flow and that'll increase pressure more and can't be guessed at. Remember, just because the additional sprinklers are not added in the original design (remote) area, they may still need to be calculated because the requirement is for the hydraulically most demanding area and you won't know that if it is non-typical spacing, pipe sizing and sprinkler types WITHOUT a calculation. In general, ask for the calculation and make sure it is the hydraulic most demanding, not the most remote, because those two are not the same and 13 requires the most demanding. Scott (763) 425-1001 Office (612) 759-5556 Cell -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Craig Rauch Sent: Thursday, February 07, 2008 8:24 AM To: [email protected] Subject: Arm over Calculations My question is regarding an existing light hazard system. We are currently using the 2002 NFPA 13. The system was calculated last year when this was a shell space as light hazard. They are now fitting this space out, and have submitted plans showing a number of arm overs and some additional heads to accommodate the layout of the space. The question has now come up as to if we should require calculations. At what point would you say the calculations were needed for this type of work? _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
