This is my fist post so I hope this is in the right forum section.
I have also searched this site and the web for an answer with no luck.

I am currently working on a pump station/ force main design and have called for a 10" surge relief valve to be installed on the header. The client has asked if the surge relief valve is needed or if it can be removed from the design. I submitted the design information to GA Industries who has performed an analysis and confirmed the need for one.

I have a basic understanding of surge (transient) pressures and how to calculate them on a simple system (Joukowsky's Equation). And that surges can cause failure and fatigue to the system.

My questions are then:
1.    How much is too much surge pressure? When it exceeds the pressure rating of the lowest rated component of the system? Or some percentage thereof?
2.    Also same for fatigue? When is it too much pressure that it will cause to much fatigue over the life span of the system?

I am sure there is a code somewhere that states this.
Basically what I am getting at is.... At what point can I say there is not enough surge pressure potential or enough fatigue potential to justify a surge relief valve.

You should be using good design techniques such as soft start equipment on pumps, silent check valves, reasonable pipe velocity, air release valves, etc. to minimize the potential for surge.

Note that the highest surge will probably occur as a result of a power failure.

If you have a large pump station, it may be cost effective to model the pump station application.

For smaller pump stations, the reference book listed below will provide you an outline of the surge analysis required.

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