SMEDIS

Scientific Model Evaluation of dense gas DISpersion models (SMEDIS)

SMEDIS was a research project funded by the European Union under the Environment and Climate Research Programme from 1996 to 1999. Its main objective was to develop a methodology for the evaluation of dense-gas atmospheric dispersion models in complex situations, particularly for cases involving obstacles, terrain and aerosols. These types of dense-gas models are often used to study accidental releases of explosive or toxic materials. The evaluation process included both scientific assessment of models and validation, where model predictions were compared to experimental data.

The project was coordinated by the UK Health and Safety Executive (HSE) with two other main partners, Cambridge Environmental Research Consultants (CERC) and Electricité de France (EDF). There were also ten associated partners: BG Technology (UK), Det Norske Veritas (DNV), the Finnish Meteorological Institute (FMI), Gaz de France (GDF), the Joint Research Center, Ispra (JRC), the National Centre for Scientific Research “Demokritos” (NCSR), Risø National Laboratory (Denmark), TNO Institute of Environmental Science (the Netherlands), the University of Hamburg (Germany) and WS Atkins (UK). Additionally, a number of external sponsors contributed both financially and technically.

One of the important deliverables from the project was a model validation database that included data from experiments selected to test models over a wide range of conditions, including: both continuous and instantaneous source conditions; complex effects from aerosols, terrain, obstacles and congestion/confinement; weak and strong density effects; neutral, stable and unstable atmospheric conditions; and a range of wind speeds, including low or nil wind. The datasets were selected from the following trials: Prairie Grass, Desert Tortoise, BA Propane, BA Hamburg, BA TNO, EMU ENFLO, FLADIS Risø and Thorney Island. A standardised format was used to present the datasets in Microsoft Excel files with the source conditions, atmospheric conditions and gas concentration measurements.

These datasets are shared here together with pre-prints of several research papers and documents that were produced during the project. The ADMLC is sincerely grateful to Bertrand Carissimo (EDF) and HSE for making this information available and allowing it to be shared with the dispersion modelling community on the ADMLC website.

SMEDIS files for download: