(153e) A Semi-Quantitative Risk Assessment Methodology to Prioritize Recommendations

Process safety engineers promote loss prevention by providing recommendations when deficiencies are observed. Deficiencies are undesirable conditions that aggravate the likelihood and/or the severity of loss events. Deviations in establishing and implementing the design intents are generally the causes of deficiencies. Any improvement needs resources, and since the resources are always limited, process safety engineers have to establish priorities for loss prevention recommendations. One appropriate way to prioritize the recommendations is to evaluate and compare the cost of risk reduction associated with the improvements. While qualitative risk analysis techniques may not be able to provide the necessary resolution to differentiate the improvements, quantitative techniques need much expertise, time, and funds. A feasible approach would be a semi-quantitative methodology with the simplifications necessary to make it easy to use, but at the same time providing the needed resolution for prioritization. This paper presents such a methodology to prioritize loss prevention recommendations. The methodology uses the concept of engineered systems, which are simply hardware (equipment or facility), procedures, or a combination put in place to serve specific functional intents. The basis of the methodology is founded in the premise that deficiencies are always associated with engineered systems and deficiencies increase their failure likelihoods. The high level steps of the methodology include: building scenario paths associated with the deficiencies, evaluating the likelihood of loss events with and without deficiencies, and finally, estimating the associated cost of risk reduction to facilitate prioritization of recommendations. A few examples are provided with the details of the methodology and the incorporated simplifications.