EXTERNAL PUBLICATIONS
HSE RR1174
Jack Rabbit II Chlorine Release Experiments: HSE scientific contribution and main findings
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SUMMARY
HSE uses gas dispersion modelling in its assessment of the hazard and risks posed by toxic and flammable substances stored at major hazard sites. For example, HSE provides advice to local planning authorities to inform their decisions on new developments in the vicinity of these sites. HSE advice aims to mitigate the potential effects on the public in the event of a major incident. HSE uses the gas dispersion model DRIFT, which ESR developed. HSE scientists undertake rigorous evaluation of the model to ensure that it is suitable: reports RR1100 and RR1101 give previous work. Evaluation includes validation against available experimental data. Because toxic and flammable substances are hazardous, the majority of high quality experimental research data is from relatively small-scale planned releases. For HSE and other regulators nationally and internationally, data from larger-scale releases using modern experimental equipment is valuable to improve understanding of potential releases and for model validation.
This report summarises HSE scientists’ contribution to the “Jack Rabbit II” large-scale experimental chlorine trials and international scientific model comparison exercise. The US-led trials took place in 2015 and 2016 at the US Army Dugway Proving Ground, Utah. The trials employed an extensive range of high precision instrumentation, gas sensors and data recording. An international model comparison exercise examined three experiments in detail for 17 models, including DRIFT. The results showed that DRIFT, currently (2022) used by HSE, gives reliable dispersion model predictions for large-scale chlorine releases. Together with other DRIFT evaluation studies conducted by HSE scientists, the results demonstrate that DRIFT is suitable to inform HSE decision-making.
This Research Report and the work it describes were funded by the Health and Safety Executive. Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.
