The Health and Safety Executive (HSE) uses a model, MCPIPIN (Monte Carlo PIPeline INtegrity), to determine failure frequencies for major hazard pipelines. MCPIPIN uses two models to calculate the failure rates: a model based on operational experience data which estimates failure frequencies for the four main failure modes (mechanical failures, ground movement and other events, corrosion, and third party activity); and a predictive model that uses structural reliability techniques to predict the failure frequency due to third party activity only. The historical failure rates used in the operational model are over 10 years old. HSE asked the Health and Safety Laboratory (HSL) to review and update the failure rates using more up-to-date fault and failure data. Data from CONCAWE (CONservation of Clean Air and Water in Europe) for crude oil and products has been analysed, as well as that from UKOPA (UK Onshore Pipeline Operators Association). EGIG (European Gas pipeline Incident Group) data was requested but was not made available. Failure rates by the four different failure modes have been derived from each of the datasets. In addition, substance specific failure rates have been derived, based on earlier analyses of appropriate combinations of UKOPA, CONCAWE or EGIG data.

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