Methodological approach for the assessment of technological risks: the tie in between european research and public authority support

Approche méthodologique de l’évaluation des risques : articulation entre recherche européenne et appui aux pouvoirs publics

Bruno Debray (1)

1 INERIS - Institut National de l'Environnement Industriel et des Risques

On July 30th 2003, a law on the management of technological risks was passed in France. This law introduced a radical change in the principles of technological risk assessment and management and land use planning around industrial sites. Initially mainly deterministic, the decision has now been taken to base it on the assessment of probability, kinetics and level of damage caused by a potential accident. INERIS, in its technical support role to the French Ministry of the Environment, has been involved in designing the methodology used to implement these new requirements. At the same time, INERIS has coordinated ARAMIS, a European project dedicated to the development of a risk assessment methodology to meet the requirements of the SEVESO II Directive. This new methodology is based on a mixed probabilistic-deterministic approach. Some of the results obtained during this project have inspired INERIS and have been introduced into French methodology, whereas ARAMIS has benefited from many ideas elaborated in the French context. To this end, both approaches propose a series of concepts and tools to assess major technological risks in industrial plants. Both rely on a definition of risk as a combination of the probability and the severity of hazardous scenarios and the vulnerability of the surroundings. Probability and severity are directly related to the types of equipment and the amount of hazardous substances in the plant and to the reliability and efficiency of the safety barriers in place to prevent accidents from occurring. Both methodologies use the bow tie method, a combination of a fault tree and an event tree, to describe accident scenarios and represent the influence of safety barriers. Both result in representing the severity and the vulnerability on maps that may be used to take land use planning decisions. ARAMIS and the new French regulatory system are now being observed closely by other European countries as reference solutions for risk assessment and land use planning.

L’accident de l’usine AZF, à Toulouse, en septembre 2001, a été le déclencheur d’une réflexion nationale sur l’évaluation des risques industriels majeurs et leur support réglementaire : les études de dangers. L’accident avait mis en évidence les insuffisances en matière d’analyse des risques dans les installations classées, expliquées en partie par l’absence de méthodologie adaptée. Pour pallier ce manque, l’INERIS a engagé des programmes d’appui aux pouvoirs publics destinés à développer les méthodes d’analyse pour la réalisation des études de dangers. Une réflexion similaire au niveau européen avait conduit à proposer le projet de recherche ARAMIS. Ces travaux ont abouti à un cadre méthodologique cohérent pour la mise en oeuvre des exigences de la loi du 30 juillet 20031: nouvelles études de dangers et Plans de Prévention des Risques Technologiques.

Domaines: Ingénierie de l'environnement

Bruno Debray. Approche méthodologique de l’évaluation des risques : articulation entre recherche européenne et appui aux pouvoirs publics. Rapport Scientifique INERIS, 2007, 2006-2007, pp.74-77. ⟨ineris-01869095⟩