(108a) Layer of Protection Analysis: Selecting Cost Effective Safety Measures

Traditionally, in process industry risks are reduced by applying technical solutions and taking organisational measures. The performance of both types of ?solutions? depends on many factors and can not easily be compared. Especially the effectiveness of organisational measures such as the use of procedures, education, training and improving the safety culture are hard to quantify. Nevertheless, in an integral approach towards safety, there is a strong need to compare both types of measures to choose the best solution for a given situation. TNO combines organisational and technical aspects in one semi-quantitative safety analysis. This analysis is based on Layer of Protection Analysis (LOPA). The LOPA results in scenario frequencies which can be compared to predefined risk tolerance criteria. If the criteria are not met, several additional measures can be added in the LOPA. Usually a couple of combinations of additional safety measures will result in an appropriate risk reduction. Frequently, the selection of the combination is based on the costs of implementation, although other combinations may lead to a significant increase in productivity. The LOPA method can be applied to find the most cost effective way to meet the criteria, taking ?not safety' benefits into account.