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Accident Damage Analysis Module (ADAM)

ADAM is a software tool developed by the Joint Research Centre (JRC) of the European Commission (EC) to assess physical effects and associated damages of an industrial accident resulting from an unintended release of a hazardous substance.

This software is specifically intended to assist the EU Competent Authorities, who are responsible for the implementation of the Seveso Directive in their countries, as well as governmental and research organisations of the EU Member States, Accession and Candidate Countries of the EU, and European Neighbourhood Policy Countries involved in chemical accident prevention and preparedness. More specifically, ADAM is designed to implement the calculation of the physical effects of an industrial accident in terms of thermal radiation, overpressure or toxic concentration that may result from the loss of containment of a flammable or toxic substance. For this purpose, suitable models have been used and combined to simulate the possible evolution of an accident, from the time of release to the final damage. In addition, ADAM will be incorporated as a calculus module within the next version of the GIS Area Risk Assessment tool, developed by the JRC, which is intended to aggregate the contribution to risk of different risk sources resulting from the single installations of different establishments located in a certain area, by including the transport of dangerous substances.

All implemented models, were tested during the research phase, and as such might provide great support to several operators involved in the industrial safety sector, such as the risk analysts, site inspectors and reviewers of safety reports. The outcome of ADAM calculations is of fundamental importance for any risk estimate, but it is also essential for decision support related activities such as, for instance, identification of cost effective protection measures, organization of internal and external emergency plans, provision of the correct information to the public, and definition of land use around an industrial facility. In addition, the analysis of the exposure to the effects of an accident involving a certain dangerous substance can also be used to assess the inherent potential of the substance to produce harm.

ADAM was funded by the Institutional programme of the EC Joint Research Centre and the EC Directorate General on EU Humanitarian Aid and Civil Protection (DG ECHO) via Administrative Arrangements on Seveso Capacity Building in EU Neighbour Countries[1].

[1] There are three Administrative Arrangements: N° ECHO/SER/2014/691549 JRC Contract No. 33545, N° ECHO/SER/2015/709788 JRC Contract No. 33957 and ECHO/SER/2016/732857 JRC Contract No. 34057 between DG ECHO and DG Joint Research Centre (DG JRC).

Introduction to ADAM 

ADAM is specifically designed to calculate the physical effects of an industrial accident in terms of thermal radiation, overpressure or toxic concentration resulting from an unintended release of a dangerous substance. The focus is on human health related impacts associated with thermal radiation from chemical fires, blast effects of vapour cloud explosions, and inhalation of toxic chemical vapours. Environmental consequences, which involve other vulnerable receptors, are beyond the scope of the current version of ADAM.

Since ADAM is expected to address the overall consequence assessment cycle, ranging from unintended release of a dangerous substance (i.e., loss of containment) to the final physical effect (i.e., hazardous event), and impact on humans (i.e., vulnerability), the overall structure of this tool consists of three interconnected calculus moduli: Source Term (Module 1), Physical Effects (Module 2), and Vulnerability (Module 3).

 The first module refers to the implementation of models for source term calculation i.e. estimate of the amount of substance released due to the assumed loss of containment. This estimate requires the knowledge of the type and amount of substance involved in the accident, the physical and storage conditions, the type and mode of rupture, and the release time. Each substance is characterised by specific thermodynamic, fluid mechanic and transport properties, which may influence significantly the release behaviour. These properties were gathered and stored in the ADAM database and are available for the calculations. The thermodynamic conditions of the storage (typically pressure and temperature) highly influence the release outcome. In particular, a substance may be stored as a compressed gas, a non-boiling liquid or a pressurised liquid. The main output of this module consists of the following information: i) release flow rate at the rupture exit or overall amount of the substance released in case of a catastrophic rupture, ii) other relevant parameters, such as substance pressure,  temperature, vapour quality and discharge velocity at rupture exit, iii) vessel response during outflow (i.e. how internal parameters vary with time). iv) flow behaviour and thermodynamic state in the near region after rupture exit caused by depressurisation (i.e. flashing), if present, v) droplets formation and rainout calculation to estimate the amount of release that remains airborne and the part of liquid forming a pool, iv) Evaporation rate and other relevant parameters when a release of non-boiling liquid or a release with pool formation are involved.

The second module uses the outcome of module 1 to estimate the physical effects of an industrial accident following an unintended release of substance and/or system failure. The calculus of physical effects depends on the type of accident. For Seveso-type establishments, typical physical effects are: (i) the thermal radiation produced by a fire due to the ignition of a flammable liquid or vapour, (ii) the overpressure produced by the blast of a vapour cloud ignited in the presence of some physical obstruction, and (iii) the airborne propagation of a toxic cloud into the atmosphere. These calculations are normally influenced by the atmospheric conditions (i.e., air temperature, air stability, wind speed) and by other parameters such as for instance average time for vapour dispersions or ignition time or ignition location for flash fires and vapour explosions. At present, the scope of ADAM relates to the consequence effects on humans. Other outcomes, such as chronic effects associated with the pollution by released substances, environment contamination of land and water due to possible releases of liquid substances, and projection of solid fragments that might result from the blast of a vessel, are not included in the scope of ADAM. The outcome of the Physical Effect module consists of: (i) 2D Map, where different colours for different physical effect values in the downwind /crosswind directions, (ii) Contours i.e. iso-lines showing each the same physical effect value in the downwind/crosswind directions. The 2D-map or the iso-contours generated may be transformed into georeferenced files (i.e. GPX, KML). If Google Earth is installed on the PC, the selection of the KML format will lead to the automatic opening of the iso-contours/2D Maps on the reference area as shown below.

 The third module is designed to address the vulnerability i.e. the level of harm produced by the physical effects, which are the outcome of module 2. This depends on the intensity and duration of the exposure to this physical effect, which can be expressed in terms of the received dose. In particular, the dose is estimated as the product of the intensity I of exposure (to a certain exponent n) and the exposure duration t, i.e. In t. In ADAM, vulnerability is primarily estimated on the basis of the probability of death of an individual or group of individuals as a consequence of the received dose. In ADAM, the log-probit method has been selected as the most simple and straightforward approach to describe the human vulnerability distribution. In order to express the lethality for any accident type, specific vulnerability probits are used for each of the following exposure route: fire, explosion and inhalation of toxics. In addition to the probit approach, ADAM allows the possibility of expressing the level of harm by also using reference damage thresholds (i.e. endpoints), which contains LC50 (30 min), IDLC and LOC triplets, as well as Protective Action Criteria(PAC) endpoints (i.e. AEGLs, ERPGs, and TEELs).

In addition to the three calculus moduli, there is a series of auxiliary modules that are necessary to run the models. In particular:

  • Input Data module: for the scenario description and associated data (i.e. substance type and amount, operating conditions and failure mode);
  • Database on Substances, containing the physical properties of the dangerous substances and the Probit parameters of the vulnerability models;
  • Environmental Conditions: to set air, weather and territorial conditions;
  • Model assumptions to select some model criteria and assumptions amongst the available alternatives;
  • Output Data module: to provide the results of the calculations. This will consist of graphs depicting the relevant parameters of the accident releases and iso-effect contours and maps to depict the consequences and lethality curves. These can also be obtained in kml or gpx formats. Output data can also be obtained in tabular forms such as Excel sheets.

 References

Fabbri, L Binda, M Bruinen de Bruin, Y; Accident Damage Analysis Module (ADAM) – Technical Guidance, EUR 28732 EN, Publications Office of the European Union, Luxembourg, 2017, ISBN 978-92-79-71879-3, doi 10.2760/719457, JRC107633.

Fabbri, L Binda, M and Wood, M; Evaluation of the Accident Damage Analysis Module (ADAM) tool - Verification and Validation of the implemented models in ADAM for Consequence Analysis, EUR 29363 EN, Publications Office of the European Union, Luxembourg, 2018, ISBN 978-92-79-94668-4, doi:10.2760/582513, JRC113187.