SAFE DRAINAGE OR LEAKAGE CONSIDERATIONS AND GEOMETRY IN THE DESIGN OFPROCESS VESSELS

Drainage and/or leakage of fluids from process and storage vessels has assumed increased importance in recent years because of safety consid erations. In some accident scenarios, it may be necessary to drain a v essel as rapidly as possible, while in others minimal leakage from the vessel may be the desired objective. The geometric shape of the vesse l clearly impacts upon vessel drainage times, in addition to the amoun t of material which can be stored therein. In this note, equations are developed which relate the drainage times for a variety of geometrica l vessel shapes to the time required to drain the equivalent volume of material from a full spherical vessel, both solely under the influenc e of gravity. These expressions may then be used as guidelines in the design of process vessels for which safe evacuation is of pressing con cern in hazard or risk analysis.