In the flat lands, you MAY have a 2 in drain that could do full flows up to OHII - depending on the configuration of the riser and drain line. But the point of the test is to compare the actual pressure drop through the backflow with the manufacturer's curve. So you must accurately measure the flow. How does one do that on a typical 2 in drain outlet?
Mark A. Sornsin, PE Fire Protection Engineer Ulteig Engineers, Inc. Fargo, ND 701.280.8591 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thom McMahon Sent: Friday, May 30, 2008 4:39 PM To: [email protected] Subject: RE: Full-flow backflow test Back to the "Main Drain Test" (Just as a note, most of our systems will flow full design, even for OH II thru a 2" main drain connection. If you install the main drain you've provided the ability to full forward flow the backflow device.) Static Psi over 120 with residual above 100 flowing over 3500 Gpm. Our normal. Those big hill's called the "Rockies" make reducing pressure our problem. A PRV station fails and we increase Psi by more than 50%. Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ron Greenman Sent: Friday, May 30, 2008 3:26 PM To: [email protected] Subject: Re: Full-flow backflow test Gregg, I was addressing older systems per NFPA 25 built to a prior code where there is no means to test full-flow and no requirement to add such a means. Even in these cases you have to forward flow as best you can. _______________________________________________ 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)
