EXTERNAL PUBLICATIONS

SUMMARY

Correlations were derived in the preceding GAME project to quantify the source strength of a vapour cloud explosion required to apply the Multi-Energy Method for the determination of blast characteristics. The correlations relate a set of parameters describing the obstacle configuration in which the flammable cloud is present and the fuel, to a single value for the overpressure in the exploding vapour cloud.

This project investigates the difficulties and problems encountered while applying the correlations to a number of realistic scenarios. The objective is to provide guidance and recommendations on how to overcome these difficulties and to decide on the actual values to be chosen for the parameters of the correlations in specific situations. The emphasis is on the determination of the parameters: ‘Volume Blockage Ratio’ and ‘Average Obstacle Diameter’.

The main finding is that a safe approach in most situations is to apply the procedure of the new Yellow Book for the determination of the volume of the obstructed region in combination with the hydraulic average obstacle diameter and a flame path length equal to the radius of a hemisphere with a volume equal to the volume of the obstructed region. Lack of experimental data on specific items prevents the generation of more detailed guidance. Some guidance is developed based on a theoretical approach, to assess the influence of the aspect ratio of the obstructed region and to quantify the separation distance between multiple explosion sources. It is recommended to perform an experimental research programme to generate the required data to improve and validate the suggested procedures.

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