Design considerations and risk assessment during HAZOP studies

OSHA`s Process Safety Management rule requires facilities to conduct process hazards analysis on all covered processes. Many facilities are in the process of conducting HAZOP studies to fulfill this requirement. The methodology used by the facilities is based on the plant`s culture and the objectives of their PSM program. This paper provides a description of a modified HAZOP methodology which combines the brainstorming HAZOP method with risk assessment. In this approach, the HAZOP method is modified to include quantitative risk assessment (e.g. vapor dispersion, fire radiation and explosion calculations) for scenarios identified to have catastrophic potential. Based on the risk assessment, the HAZOP team interactively develops engineering solutions to minimize or eliminate the risk potential. The use of this modified method leads to improved identification of hazard potential and also eliminates the need to revise the HAZOP to include off-site consequences when the proposed EPA rule for risk management programs is finalized.