Process Hazard Analysis, Hazard Identification and Scenario Definition: Are the conventional tools sufficient, or should and can we do much better?

Highlights

• •The weakest link in risk assessments is hazard identification/scenario definition.
• •Existing methods, such as HAZOP and FMEA, do not guarantee completeness.
• •Attempts to semi-automate HAZOP on plant do not seem to be fully satisfactory.
• •Only a system approach can provide completeness on plant, people, and procedures.
• •New possibilities are reviewed including an operational use of HAZID results.

Abstract

Hazard identification is the first and most crucial step in any risk assessment. Since the late 1960s it has been done in a systematic manner using hazard and operability studies (HAZOP) and failure mode and effect analysis (FMEA). In the area of process safety these methods have been successful in that they have gained global recognition. There still remain numerous and significant challenges when using these methodologies. These relate to the quality of human imagination in eliciting failure events and subsequent causal pathways, the breadth and depth of outcomes, application across operational modes, the repetitive nature of the methods and the substantial effort expended in performing this important step within risk management practice. The present article summarizes the attempts and actual successes that have been made over the last 30 years to deal with many of these challenges. It analyzes what should be done in the case of a full systems approach and describes promising developments in that direction. It shows two examples of how applying experience and historical data with Bayesian network, HAZOP and FMEA can help in addressing issues in operational risk management.