Pressure Relief System Reaction Forces – The Importance of Evaluating Existing Installations

摘要

Overpressure protection analysis has evolved significantly since the inception of the PSMstandard, but the mechanical stress applied to the piping during overpressure eventsappears to have been overlooked. Recent events have led several facilities to requestmore attention be paid to the effects stresses induced from relief device discharges haveon their piping. The purpose of this study is to allow an existing facility to focusresources on the relief device installations most likely to fail due to reaction forces. Aseries of representative installations were evaluated in order to determine whichparameters associated with pressure relief have the strongest impact on the installations,with particular concentration on the dynamic effects of the release. Screening criteria foridentifying pressure relief device installations which may exceed the allowable pipestress levels were developed from these systems. When evaluated against apetrochemical facility’s pressure relief systems and benchmarked for its validity as a firstpass tool to identify potential installations that may require further analysis or additionalphysical supports, is was found that over 30% of the existing installations may requiresupport for reaction forces.