Risk-Based Inspection (RBI) of Steam Systems

Abstract

This paper describes the implementation of a risk-based inspection program for process and utility steam lines in a large chemical process facility. The paper addresses the development of an RBI matrix, the likelihood attributes, the consequence scores, and the overall risk in terms of personnel safety and costs. The likelihood of failure considers prior experience, degradation mechanisms, novelty of process, abnormal loads and age. The consequence of failure considers public health and safety, worker health and safety, environmental impact, operations impact, and recovery costs. Once assigned a likelihood and consequence score, systems are plotted on the RBI matrix to develop inspection priorities. The RBI ranking determines which systems will be inspected (high risk) and those that need not be inspected (low risk). The risk ranking is followed by inspection planning which includes selection of the inspection technique and inspection locations, together with the development of pre-inspection acceptance criteria.