A toluene surge drum has capacity 500 gal and is normally operated 60% full at 100 ºF under 300 psig of hydrogen in the head space using a level controlled outflow. The normal flow rate into the vessel is 30,000 lb/hr. Determine the vessel dimensions if the vessel is vertically mounted. Evaluate the relief loads for the blocked outflow and external fire cases and hence determine the relief valve size.