Per edition 5 of the American Mutual Insurance Alliance Simplified water supply testing "In testing a water system at a sprinklered plant, sometimes we can note the residual pressure from a gauge at the base of the nearest riser. This is not recommended as standard practice, but may be used when other methods are not practical."
The reason to flow past the "Test Gauge" is as George said, the velocity pressure will give a lower residual than on a dead end main, where velocity pressure will create an artificially high residual. In either case as is often pointed out by Roland, "Does the difference between 56.017 Psi and 56.049 Psi really make a difference" when we then add a 10% or 10Psi safety factor, and assume a relative C value for existing underground pipe. 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 George Church Sent: Friday, January 23, 2009 12:56 PM To: [email protected] Subject: RE: water test location You're not affected by the velocity pressure of the water going past your hydrant, that'd introduce errors -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Dewayne Martinez Sent: Friday, January 23, 2009 12:52 PM To: [email protected] Subject: RE: water test location George, I thought that if you did not flow past your gauge hydrant that your residual reading would be off. Have I been wrong all these years? _______________________________________________ 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)
