Fire Scenario restrictions?

[Bourbon103]

I have a heat exchanger that external fire is considered the controlling scenario for over-pressurization. Currently, relief is in the form of a 6" x 10" relief valve on the inlet to the shell ~1000 ft. away in another building.

I know per ASME XIII that an ASME coded vessel requires at least a minimally sized relief valve on its shell. Is there a restriction as far as how "local" the relief valve needs to be or is the only requirement that it passes 3% inlet pressure drop?

 

[korn]

I don't know of any absolute distance restrictions for vapor scenarios (other than 3% loss as you mentioned). But you are going to need a long run of large pipe to keep under 3% (if even possible). This is going to be a high installation cost solution. Try adding fire proof insulation or something like that to reduce the required rate and decrease the size of that relief valve.