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[Cheme2020]

Hi,

I am trying to size a relief device on a fire water pump. I am looking at past files and the controlling scenario is failure of controls aka the overspeed trip system fails. An engineer skilled in this field said the relief device should be sized to relieve the water until it gets to below the rated pressure of the relief device and not relieve all of the water since relief devices should not be used as pressure controllers. However, shouldn’t the relief device relieve the flow rate on a overspeed pump curve at the rated pressure and relieve at the given flow rate? The engineer said it should only be able to relieve 110% of the speed of the pump and to ignore the scenario…

[breizh]

Hi,

Consider this old version of NFPA to support your work in particular part 2-13.

Good luck

Breizh