This article deals with the design considerations for several plant containment systems that were installed as pan of the emergency pressure relief system. In all cases, the quench tank approach with vapor suppression was utilized. The examples presented include: (1) multiple batch reactors handling vinyl monomers, (2) multiple initiator charge vessels, and (3) multipurpose batch reactors with possible Grignard-type reactions' The design considerations include: quench fluid selection, sizing of the quench tank,,fluid mixing, sparging dynamics, vapor condensation efficiency, and post relief beatup. (C) 2006 American Institute of Chemical Engineers.