Backflow Preventer in Pump Suction

[alexcmmi]

Municipal Water Distribution Application - Potable Water

We are trying to design a very basic water booster station to provide adequate pressure to a proposed development located 'up a hill'.

Pump station is to be designed w. 1 jockey, 2 duty and 1 high flow pumps. Minimum suction pressure into the station from the muni distribution system is around 60 psi - adequate.

Unfortunately the municipal water department does not have any experience with pumping into a closed looped system - thier entire distribution system is head driven (elevated storage). No booster stations in town at all

Since the water will be metered BEFORE the station (in suction) they are also requiring (want) a backflow preventer within the pump suction line.

Is this possible? I am sensing if anything, a double check will work much better than a RPZ. But what if the backflow preventer fails / sticks? Couldnt this be a huge disaster, especially if it happened during high flow and all of a sudden water wasnt avaialbe to fight a fire?

Any suggestions to talk them out of this, or any advice in general.

Much appreciated.

 

[BigInch]

I don't do muni systems, so be warned.

If the backflow preventer fails, you buy water twice if the pump backspins when its off. If the pump fails you have no firewater. For firewater systems at least 2 x 100% pumps is the usual minimum (plus a jockey pump) for reliability reasons. You might consider the same. Otherwise I would imagine you will probably have to have a firewater supply somewhere up the hill.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

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