Failure data within PIPIN
The health and safety executive’s pipeline failure rate calculation model


Harpur Hill, Buxton, Derbyshire, SK17 9JN, United Kingdom


The GB Health and Safety Executive (HSE) uses the PIPINV3 model to predict failure rates (failure frequencies) for major accident hazard pipelines. PIPIN was developed in the 1990s but has since been rewritten to incorporate a new solution method, modifications to the science, and updates to the historical data used in both a predictive model and an operational experience model.
This paper provides an overview of the different types of data used in the model and the process undertaken to update this data. Comparison tests of the updated version of PIPIN with an earlier version of the model were undertaken. The results generated indicate that the failure rates are reduced on average with the inclusion of the updated data.


The author would like to acknowledge the help of UKOPA (UK Onshore Pipeline Operators’ Association) who provided the raw data used in this work.

This publication 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 authors alone and do not necessarily reflect HSE policy.



The GB Health and Safety Executive (HSE) uses a fracture mechanics model, PIPINV3 (PIPeline INtegrity) (1, 2, 3, 4, 5), to calculate failure rates (failure frequencies) for major accident hazard (MAH) pipelines. The results are used in a pipeline risk assessment model to determine land-use planning (LUP) zones around the pipeline. The LUP zones are used by HSE to provide advice to local planning authorities on proposed developments near a pipeline, on potential modifications to existing pipelines, and on proposed new pipelines.

Four failure modes are considered; external corrosion, mechanical failures, natural ground movement/other failures and third party activity (TPA). Third party acti ...