Bobby, Do you know what kind of flow you get through the fire main from the city water supply? You need to know if there's enough pressure to overcome the tank height and be able to fill the tank in the appropriate amount of time per NFPA 22.
NFPA 20 gives you the option of discharging the flow meter output back into the suction side of the pump, there are however some issues and restriction on the installation. One issue is that by creating this closed loop, you do not test the suction supply system piping, valves, etc. If possible it is often preferable to take the flow meter discharge back to the tank. This is mentioned in A.5.19.2.1.1. If you have NFPA 20, 2007 check out some of the information in A.5.19.1.1 - 2. 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 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bobby Gillett Sent: Thursday, April 02, 2009 9:25 AM To: [email protected] Subject: Fill line for suction tank We are working on a project where the owner has an electric fire pump fed from the city water supply charging a 10" loop around the facility. At the back of the property they want a water storage tank with a diesel pump for back up. The insurance company is allowing the tank to be filled from the charged UG loop. I plan on installing a pressure sustaining alt. control valve and have the pressure set to allow the jockey to come on when the ACV opens but not the electric fire pump. How about sizing the ACV and fill line?. And does this scenario sound correct? They also want a metering device for the pump instead of a test header to recirculate the water back into the tank. We plan increasing the fill line to 8" (required size per NFPA for metering device of a 2000gpm pump) and connecting the discharge piping from the metering device to the fill line between the tank and the discharge control valve of the ACV. Does this scenario sound correct? Thank You, Bobby Gillett Sr. Project Manager Key Fire Protection, Inc. (731) 424-0130 office (731) 424-9285 fax (731) 267-4853 cell <mailto:[email protected]> [email protected] _______________________________________________ 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) _______________________________________________ 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)
