NFPA 25 requires a full forward flow test - NOT a test of the water supply curve for the BFP. Put simply, the only thing you have to prove is that you moved the amount of water equal to the system demand through the BFP. Show the Q and that's it.
The intent is to fully exercise the BFP and provide a REASONABLE test that it will fully open. This is not to be considered a formal interpretation by NFPA or any of its technical committees but look at the ROP/ROC for the last cycle of NFPA 25 and it is explicitly addressed. Roland On Jun 9, 2009, at 1:58 PM, Thom McMahon wrote: > This is most likely just for re-certifying the device. There is no > ASSE > requirement to forward flow test backflow devices for re- > certification. > Re-cert. is typically a dept of health, or environmental issue. > > Remember that the full forward flow requirement is an NFPA thing, > and many > have rightly argued that this means "at system demand" So if you > have a LH > system, with reduction for QR and only demand 99 Gpm, cause there is > no > inside hose, most likely you can flow that through the main drain. > Here in the mountains with static and residual pressure of over 100, > we can > flow over 800 gpm out the main drain. Good for 2 standpipes. > > Remember what you're looking for when you forward flow the device. Any > pressure loss greater than was used in the calc's that could > undermine the > system operation at its original design. The bigger question is how > do you > know what that loss is that was used in the original calc.? The best > you can > do is see if it is in the MFG's literature range. > > > Thom McMahon, SET _______________________________________________ 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)
