The effectiveness of fire air release valve has been investigated when offshore process equipment is exposed to a fire. Simulations of several typical offshore pressure vessels have been performed using the commercial software VessFire. The pressure vessels are exposed to a small jet fire, large jet fire, and a pool fire on both the wetted and unwetted part of the vessels. Rupture times of the vessels are calculated by comparing the pressure in the vessel with the tensile strength of the material.