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When installing a diesel pressure limiting driver (PLD), it is necessary to multiply the shutoff pressure by 121% to calculate the maximum discharge pressure?

Question asked by zurlofranco on Oct 30, 2017
Latest reply on Oct 31, 2017 by d.macdonald

I have to install a centrifugal fire pump with diesel pressure limiting control driver (PLD) by variable speed control. The shutoff pressure at rated speed is 163 psi while the maximum working pressure of the system components is 175 psi, the doubt is whether to install a main pressure relief valve or not. In fact, if 4.19.1.2 of NFPA 20.2016 is to be applied, the shut off pressure must be multiplied by 121% and then exceeded the maximum working pressure of the component components of the system, so it is necessary to install the  main pressure relief valve. Apply only point 4.19.1.3 of NFPA 20.2016 the shutoff pressure is only adjusted for elevation, not exceeding the maximum working pressure of the system components, so the main pressure relief valve should not be installed.
What is the correct solution?

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