A simple model for the release rate of hazardous gas from a hole on high-pressure pipelines

It is very important to estimate the mass flow rate of possible accidental releases from the gas pipeline, in order to perform the hazard analysis or the risk based management in the gas facilities. This paper presents a simplified model to estimate the release rate from a hole on the high-pressure gas pipeline. It consists of a correction factor accounting for the pressure drop through pipeline due to the wall friction loss, and the release rate without friction loss. The model, whatever kind of gas may be considered, has some positive deviation from the theoretical complex equations, and it ranges from about 0 up to 20%. The deviation will reduce to zero, as the release point approaches to the reservoir. It increases with the specific heat ratio of gas and the dimensionless hole-size which is the effective area of the hole divided by the cross-sectional area of the pipe. The model is compared with damage areas of real accidents with success. It overestimates the release rate slightly and may be a useful tool to estimate the release rate quickly in performing the hazard analysis or the risk based management in the gas facilities.