Abstract
The risk assessment analysis is perceived as the most important stage in preparation of the major accident prevention documentation in accordance with the Directive 96/82/EC. The risk assessment alone is a complex process and several procedures and their modifications have been developed in practice, using various approaches to the task. ARAMIS (Accidental Risk Assessment Methodology for IndustrieS) methodology (Hourtlou, Salvi, 2003, ARAMIS, 2004) has been developed in order to unify the approach to risk assessment for major accidents and their impact on the environment.
Project ARATech2013 – a tool for major accidents risk analysis, has been established with the aim to transform ARAMIS complex procedures into a software tool, which will simplify and make the risk assessment techniques more readily accessible. It is the coherence of the ARATech2013 tool and the number of prearranged and recommended steps that provide the wider user base with a useful alternative to the commonly used and often technically and methodologically challenging deterministic and probabilistic approaches used for risk assessment.
ARATech2013 is a web-based modular tool, which enables to alternatively expand the functionality of the tool or gives its users the option to follow a simple pre-selected pathway without having to follow the entire major accidents risk assessment process. The tool is based on the following three core modules:risk source assessment module,representative scenarios determination module,accident impact assessment module.
The risk source assessment module presents the initial stage of the risk analysis process. The users use the module to establish the basic information about the facility, i.e. a list of all types of equipment containing hazardous substances, physical - chemical properties of hazardous substances, their physical state and amount. The application automatically identifies the potentially hazardous equipment to undergo further detailed analysis and matches this equipment with appropriate potential critical events. The user is provided with an ability to add supplementary information for determination of potential domino effects.
The representative scenarios determination module computes the frequency of various hazardous effects for the determined critical events. Each critical event is automatically assigned generic fault trees (Fault Tree Analysis - FTA) and event trees (Event Tree Analysis - ETA), which can be further modified by the user to match the real situation in the given establishment. The user has the option to use a generic frequency for each critical event or to determine the frequency using the in-built Fault Tree Analysis. The module offers a database of complex check lists of safety functions and barriers, which the user can assess and apply individually to each fault or event tree. This makes the tool highly valuable for assessing the effectiveness of risk management systems.
The accident impact assessment module is an independent module for modelling of the hazardous event and the spatio-temporal distribution of hazardous effects. The model distinguishes among the different types of release of the substance from the equipment, the consequent cloud formation and its dispersion with the toxic, radiative or pressure effects. The module is interlinked with a web mapping portal for a quick projection of the impact of the hazardous event.
