Systems aimed at ensuring the integrity of a pipeline use a combination of operational procedures, maintenance procedures, and dedicated hardware and software as part of an overall pipeline integrity management system (PIMS) to provide advance warning of any events or changes in the physical state of the pipeline which may lead to a loss of integrity. However, it is inevitable that leaks will occur. Leakage detection therefore forms a key part of the total strategy and the selection of one or more leak detection systems must be made within the context of an overall PIMS. Although there is no single ideal approach, several of the currently available technologies can work in a complementary fashion, greatly expanding the range of leaks that can be detected. In terms of the most important criteria (response time, leak size and ability to handle transient conditions), real-time transient modelling and statistical analysis appear to be the most successful but this must be balanced against their data requirements, complexity and cost. It is clear that practices differ from sector to sector and the very different operational regimes of, and potential hazards from, oil, gas and water pipelines, mean that transferring best practice from one sector to another is not simply a matter of implementing an identical solution. The key recommendation with regard to the selection of any leak detection system therefore is that it must be made within the context of an overall pipeline integrity management plan. This will ensure that, as far as possible, the system or systems chosen address the specific requirements of the pipeline and its interactions with its environment. Even within each sector, there is considerable variation in best practice, both in terms of implementation by pipeline operators and the solutions offered by leakage detection system providers. Whilst the decision-tree-based approach can provide an indication of systems that meet the technical criteria, it is important to speak to other pipeline operators, in other sectors if appropriate, but certainly within the sector.
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