Looks like you could be above 200 PSI churn or system pressure. The standard (2013 referenced) does not allow you to use the relief as a means of blowing off excess pressure above 175.
Tom Is the 140 psi total pressure or pump rating? The pressure relief valve comes into play if the combination of supply pressure and pump pressure exceeds the allowable system pressure, which for most cases is 175 psi. So if you had fluctuating supply pressures, during a higher than normal pressure event, the system could relieve and not damage your downstream, 175 psi rated system. Is this a diesel or electric? How much pressure do you need at these heads? Craig L. Prahl Hi Forum , Could someone shed some light on the requirements for 4.7.7.2 . I have a project where the quoted fire pump comes with a Pressure relief valve and waste cone . City pressure is 58/56/1586 , we are using a 1500gpm pump at 140 psi to get the flow and pressure we need to supply a freezer using LP-46 heads . I find many references to the use of Pressure relief valves being Used but 4.7.7.2 is causing me to scratch my head . Colin
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