Chapter III - Qualitative Hazard Analysis

Abstract

Qualitative hazard analysis is mainly utilized during the early stage of the project in its life cycle. Preliminary hazard analysis has been used extensively for early-stage hazard analysis in many industrial plants. In preliminary hazard analysis, hazards are identified, listed, and then analyzed with respect to their occurrence, frequencies, and consequences. Based on the risk matrix, risks are ranked. Based on risk ranking, control measures are developed. “What if” is based around brainstorming analysis by a small team of highly experienced engineers, but it is not systematic. Here, hazards are identified with the help of answering a set of questions asked in the form of “What if.” After frequency and consequence analysis, control measures are developed, to bring down the risk level to as low as reasonably practicable. A more structured method of analysis is checklist analysis, which uses a set of checklist points. Against this checklist, the design and operation of the plant are assessed. For deficiencies, necessary control measures are prescribed. There is another kind of qualitative hazard analysis: the “what if” checklist, where both methods are combined so that it is structured and uses the experience of the team to analyze the system. In all cases, suitable team selection, timing, and scope boundary definitions are very useful.