T10-1 - The ‘Purple Book’: Guideline for Quantitative Risk Assessment in the Netherlands

Abstract

A Quantitative Risk Assessment (QRA) is a valuable tool for determining the risks related the use, handling, transport, and storage of dangerous substances. QRAs are used to demonstrate the risk caused by an activity and to provide the competent authorities with relevant information to enable decisions on the acceptability of the risk related to developments on-site or off-site. QRAs are made on the basis of similar starting-points, models, and basic data. Ideally, differences in QRA results should only arise from differences in process- and site-specific information. Purple book can be described as a guideline in which all necessary starting-points and data needed to perform a QRA calculation in compliance with the regulations in the Netherlands are recorded. The Guideline also records the motivation for certain decisions and the base used for specific data and their validity. The Guideline comprises a method to select installations to be included in the QR—a set of default loss of containment events—default values to be used in the dispersion and effect calculations, and provides guidance on presentation of the results.