What types of bypass can be used if there is a recertification on PSV valves if pressure increases.

[Vivaldi SMITH]

I have this doubt, They are going to recertify couple of PSV's in the Unit, but I was wondering if one assesment I should consider is opening the bypass around a thermal relief Pressure Safety valve, if pressure increases close to PSV set point.
What about fire PSV?

 

[1503-44]

You should isolate the valve for testing purposes, not create ab overpressure situation in the piping itself.