Optimising the land-use around transmission pipelines

This paper shows that the present more simplified approach to risk assessment for high-pressure hydrocarbon pipelines is somewhat conservative. The outflow modelling is more complex that might be predicted by the traditional, simple outflow equations due to two-phase formation in gas pipelines and froth formation in oil pipelines. The consequence models for jet fires, historically based on flare type model, are shown to be conservative. Taking these two points together the magnitude of the hazards can be overstated. The failure rate data for (underground) pipelines show that the greatest causes of massive releases are due to mechanical faults and third party intervention. When these effects are dealt with through design standards and policing of the pipe corridor the full bore failure rate of oil and gas pipelines is very low, 2 x 10(-5) per kmyr which indicates that the frequency of the hazard is probably significantly over stated. Taking all of the results together, both failure data and modelling, and knowing the specifics of each case, the assessed risks for land-use near Transmission Pipelines will be reduced, so releasing land for use in strategic areas.