When evaluating a relief valve to protect the shell side of an exchanger being fed the tops from a stripper (i.e. a condensing exchanger) does one use the wetted wall (liquid to vapor) approach or the unwetted wall (gas to gas) approach?

Just to understand a bit more...

Is the condenser Shell & Tube type or air-cooled type ?

Is the condenser mounted on the top of stripper ? How height is the condenser ? Do you consider jet fire is credible scenario ?

Shell and Tube about 15 feet above grade. I am not worried about a jet fire. I am just wondering whether I should perform the calculations assuming I have a gas situation or if I have a vaporizing liquid situation. Since the exchanger is a condenser, I should have some liquid in the the shell - therefore it seems I should use the "vaporizing liquid" case. Thanks.