A key requirement for a successful Major Hazard Facility Safety Case is “demonstration of adequacy of critical risk reduction measures” to a Regulatory Authority. This is often done via costly and detailed Quantitative Risk Analysis. Effective, simplified quantitative methods are presented to achieve the same purpose.

Simplified quantitative methods/tools that have proved successful are:
• Layers of Protection Analysis (LOPA);
• SIS Analysis; and
• Cumulative Risk Assessment Methods (CRAM)

The use of these tools enhances the process of “demonstration” required for successful licensing for operation of MHF’s.

The following will be discussed:
• Hazard identification steps in a QRA.
• Frequency assessment to determine likelihood of a hazardous scenario.
• Consequence effects - the determination of the expected consequence zones.
• Risk representation. An effective method for determination of Aggregated Risk is demonstrated. Case studies and the experience with a number of Safety Cases are given.

Various risk and modelling tools used for this purpose will be discussed. This includes:
• FE Jet & Pool Fire Models ©MatrixFire
• CFD Fire Models
• Cumulative Risk Assessment Package ©MatrixQRA
• HG Systems
• Slab
• Austox