The Health and Safety Executive (HSE) is a statutory consultee for land use planning applications around onshore major accident hazard pipelines. HSE’s advice is aimed at mitigating the effects of a major accident on the population around such pipelines. This advice is informed by the use of mathematical models of potential hazards. HSE has an ongoing research programme to assess the suitability of the models used.
One of the potential hazards considered is a fireball or a jet fire that produces intense thermal radiation. A fireball occurs when there is immediate ignition of a pressurised release of flammable material in the event of a vessel or pipeline failure. A jet fire can occur underneath a fireball and remain after the fireball has dissipated, or if ignition is delayed.
A new model is proposed for fireballs whilst modifications are suggested to the existing non-natural gas jet fire model with an extension of its use to natural gas pipelines. Comparisons are made against data identified in the literature and the results indicate that the proposed models perform reasonably well.
Comparisons of total predicted risk levels using HSE’s pipeline risk assessment model indicate that the overall effects on the natural gas pipelines were to either slightly reduce the risks or to have no significant change. For non-natural gas pipelines, there was a slight overall increase in the risks. The report will be of interest to specialists in risk modelling for major hazards.
This 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.
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