Quick links: Source term sensitivity ADMS-Puff development ADMS-STAR development SMEDIS
CERC has extensive experience in modelling hazardous releases, starting 30 years ago with modelling of the 1987 King's Cross Underground fire for the UK HSE, and continuing with the development of the GASTAR model for dense gas dispersion in 1988 and the liquid spill model LSMS in 1989.
The term 'Hazardous Releases' relates to situations posing an acute risk to human life, which are assessed in the UK under the Control of Major Accident Hazards (COMAH) framework. As part of our consultancy work, we have modelled a large variety of hypothetical hazardous releases including warehouse fires, catastrophic vessel failures and liquid spills, with emitted substances which may be toxic, flammable or explosive. We have also been key partners in projects to determine the best practice for modelling of hazardous releases.
Some accidental releases would not be considered ‘hazardous’, although they may have some human health impacts. CERC has worked behind the scenes on several recent high-profile legal cases relating to fires which were in this category.
CERC have developed a number of software tools for modelling hazardous releases:
Defining source terms is an essential part of dispersion modelling. A substance can be released into the atmosphere in many different ways, particularly in accidental release situations. It is important to have an understanding of the sensitivity of the model results to each of the source term input parameters. CERC and GT Science & Software Ltd carried out a ‘High Level Review of the Sensitivity of Dispersion Model Predictions to Individual Source Term Parameters’. This work was funded by the UK Atmospheric Dispersion Modelling Liaison Committee (ADMLC).
The review discusses the main issues of source term sensitivity, describes a range of commonly-used dispersion models, and presents the results of detailed sensitivity tests. The source terms examined in the review include evaporating pools, catastrophic failures of pressurised vessels, jet releases, spray releases, warehouse fires and pool fires. The report describing the outcomes of this review was published in January 2017 and is available for download from the ADMLC publications webpage.
ADMS-Puff was initially developed by CERC for clients in China. Alongside the features available in the public release of ADMS-Puff, additional features were added allowing the client to use their own flow field data directly in the model.
ADMS-STAR was initially developed in conjunction with a UK government agency to model the dispersion and deposition of material from accidental releases, including comparisons against maximum permitted levels in foodstuffs. Additional development has been carried out to incorporate new features at the request of clients, including the ability to include the effects of spatially varying meteorology and additional output options.
Between 1998 and 2000, CERC were involved in coordinating the EU SMEDIS project concerned with developing a protocol for the scientific evaluation of dense gas dispersion models. The project had particular emphasis on the complex effects of obstacles, terrain and aerosols often found in real situations, and involved validating the models against field data. CERC’s dense gas model, GASTAR, was one of the models used in the evaluation process.
Project funded by the European Union under the Environment and Climate Research Programme part sponsored by EU.