Quantitative and Semi-Quantitative Risk Assessment Techniques and Applications
(BSI EHS Services and Solutions)
Determination and use of a specific risk assessment technique is driven by the goal of the assessment itself. Most process related systems, both batch and continuous, are best reviewed by qualitative or semi-quantitative methods since they have time dependent variables that play a large role in events that lead up to a hazardous condition. Conversely, systems that are hardware or equipment centric, can be effectively assessed by use of quantitative methods, especially for systems where mechanical system failures or a series of cascading failure modes can result in undesired events with serious consequences. Most manufacturing and process systems are assessed using qualitative methods, which are effective in reviewing system-wide deviations or failures and focus on the ability of the design and related human interactions to successfully complete the system mission without failures and serious consequences. There are however situations where semi-quantitative and quantitative risk assessments are needed to provide a more focused evaluation of hazard scenarios, determination of critical interventions (preventive/corrective maintenance) and assurance that critical single point failure controls are adequately reliable and multiple layers of independent controls are applied as appropriate. This presentation will focus on several quantitative and semi-quantitative techniques and present examples where these have been effectively applied.