Public safety risks are becoming an important issue in the planning of new pipelines and the operation of existing pipelines. Pipelines are initially routed to avoid densely populated areas. However, new developments may encroach on existing pipelines. Risks to the public can be estimated to determine an adequate setback distance.

The methodology for risk assessment is described using a Canadian case study. Ethane, propane, butane and pentanes are commonly transported as liquids in pipelines. These compounds have a high vapour pressure, and when accidentally released, may form a flammable dense gas cloud. If the cloud is ignited, a flash fire or vapour cloud explosion may occur. Consequences and frequencies of the selected hazardous incidents are provided. Individual risk levels in rural and urban areas along the pipeline are presented and compared to the risk-based land use planning guidelines of the Major Industrial Accidents Council of Canada.

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