What kind of pressure reducing valve? There are fixed pressure (control) valves and then more conventional ones that have a differential, which will make for a discharge pressure curve, depending on inlet pressure. SAFEST thing to do is take serial number off of valve and contact manufacturer for tech data on that exact make/model, then build a flow dependent pressure loss device curve at that node, presuming your software lets you do that.
Steve Leyton Hazen-Williams, PA -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ralphy Henderson Sent: Tuesday, June 19, 2012 2:04 PM To: [email protected] Subject: Calculating Pressure Reducing Valves I have an existing install that needs to be re-calculated due to some modifications. The system has a booster pump and downstream of the discharge, before the feed main disappears into the structure, there is a pressure reducing valve which is sett to 150 psi. I would like some confirmation that I'm calculating this thing right (hydracalc). I've set up a couple of nodes for the PRV and for the first run I set the friction loss at 0 to get an idea of what the discharge pressure is at the point of the PRV. Then I basically go back and enter in the difference of the pump net pressure and the PRV setting of 150 psi as the fixed friction loss through the PRV's nodes. So for example, let's say the pump is capable of 200 psi at my system demand and the PRV is at 150 psi - I set the fixed friction loss at the PRV to 50 psi to achieve the pressure reduction. Does this sound about right? This is more of a software question than anything I suppose but any input is appreciated. Thanks! RB -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attach ments/20120619/158d91e4/attachment.html> _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
