Comparison of Qualitative Methods of Risk Inspection and Analysis

In this article the most important qualitative risk assessment methods have been compared and evaluated structurally and functionally. In this work the methods like Check- list, What-If, Failure Modes and Effect Analysis, Hazard and Operability, Fault Tree Analysis and Event Tree Analysis have been studied. In the first section, a brief description of each method has been presented then application of each one has been presented. Finally a comparison among different approaches has been executed. The results show that simultaneous utilizing of inductive and deductive methods are necessary for a reliable risk assessment. Various parameters such as budget, the time limitation, type of process and equipment type are effective in selection of risk assessment methods. Application of Check list combined with Fault Tree Analysis is the most economic approach. On the other hand HAZOP in combination with Fault Tree or Event Tree is the most reliable technique while it is the most expensive.