DETERMINATION OF SAFETY INTEGRITY LEVELS TAKING INTO ACCOUNT ALARP - COST BENEFIT ANALYSIS

摘要

There is a considerable gap between the current guidance on ALARP which is concerned with total annual risk from all hazards and the situation facing designers of functions within safety instrumented systems protecting against single hazards. Thus designers are currently forced to develop their own rationale for implementing SIS to meet ALARP requirements. This paper has made suggestions for setting tolerable risk targets, or safety targets, for single hazards, and it has also indicated how these can then be developed to demonstrate ALARP through cost benefit analysis. The purpose of this paper is to stimulate discussion and promote the need for further guidance on ALARP from a Safety Instrumented Systems perspective.