EXTERNAL PUBLICATIONS
HSE HSL/2006/45
Evaluation of the Workbook on Gas Accumulation in a Confined and Congested Area
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SUMMARY
In 1997 a JIP was undertaken on “gas build-up from high pressure natural gas releases in naturally ventilated offshore modules”. As a consequence of the JIP, a workbook was created. The workbook aims to provide a quick, first pass, technique for estimating the flammable volume arising from the release of a material within a confined, and congested, naturallyventilated offshore module. However, the workbook has not, to HSE’s knowledge, undergone independent assessment of its scientific basis. Neither does it appear that its performance has been evaluated against offshore measurements or the results of more detailed modelling. Hence its range of applicability and predictive capability are not well understood. The objectives of the present project were to:
- Examine the assumptions made in the workbook and comment on their likely effect on
the results; - Compare the workbook predictions of ventilation velocity against offshore
measurements; - Compare the workbook predictions of ventilation velocity and gas cloud size against an
existing database of Computational Fluid Dynamics (CFD) results; - Review BS EN60079-10:2003 and compare the methods described for estimating
ventilation rates and flammable volumes.
This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author(s) alone and do not necessarily reflect HSE policy
