EXTERNAL PUBLICATIONS

SUMMARY

Offshore installations must have a temporary refuge (TR) for use by workers in the event of a major fire or explosion incident. The importance of an effective TR was highlighted by the 1988 Piper Alpha disaster in which 187 workers died. Duty holders must establish suitable TR performance standards to protect workers. HSE Research Report RR1167 describes a model to estimate the time taken for workers in a TR to become impaired due to ingress of smoke or flammable and toxic gases. Another important consideration is effective protection for workers from heat stress. This is to prevent harm to workers and ensure that they can make rational decisions on management of the incident, including evacuation from the platform.

This report describes the development of a model to estimate the time taken for workers in a TR to become impaired due to heat stress in the event of an incident. The model is based on reviews of: heat transfer models; methods for relating heat exposure (thermal load) to heat stress in people; and TR standards and construction methods. The report will be of interest to specialist modellers in industry in the determination of TR performance. The model uses a simple one-dimensional heat transfer calculation to determine the bulk temperature change in the TR, and an existing model for heat stress. This approach is an extensive simplification of a complex three-dimensional scenario. The main benefits of this simple model are that it is straightforward to implement. Therefore, it can be used to give an indication of the effectiveness of changes to a TR design such as extra insulation or reducing the air change rate, as well as to assess the effect of uncertain modelling data.

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.