Pipeline networks are the most economic and safest method of transport for mineral oil, gases and other fluid products. Pipelines have to meet high demands for safety, reliability and efficiency. Most pipelines, regardless of what they transport, are designed with a lifespan of around 25 years. When they do begin to fail, they do so slowly beginning with leaks at poor construction joints, corrosion points and small structural material cracks, and gradually progress to a catastrophic ending. But there are also other reasons for leak disasters such as accidents,terrorism, sabotage and theft. The primary purpose of leak detection systems (LDS Systems) is to assist pip eline controllers in detecting and localizing leaks. LDS Systems provide an alarm, and display other related data to the pipeline controllers in order to aid in decision making. Pipeline leak detection systems are also beneficial because they can enhance productivity and system reliability thanks to reduced downtime and reduced inspection time. LDS Systems are therefore an important aspect of pipeline technology. This report presents an overview about the most commonly used principles for leak detection (and leak localization). The main focus is on “internal” LDS systems, which utilize field instrumentation (for example flow,pressure and fluid temperature sensors) to monitor internal pipeline parameters. A significant part of this report is dedicated to model based leak detection which is usually called Real Time Transient Model (RTTM) based LDS, and in particular Extended RTTM based LDS which combines computer based modeling and simulation techniques with statistical leak classification (or leak signature analysis). In this, the second edition, chapters about instrumentation issues, data communication (SCADA) and leak monitoring in shut in conditions have been added. Furthermore, enhancements of PipePatrol Statistical Line Balance (SLB) have led to substantial revisions of the related chapter. A comparison of all presented principles and methods is also included in the text, which may help the reader to select a leak detection principle that is most suitable for a particular application. Characteristics are listed on an informative basis, and while they are to some extent subjective by nature every effort has been made in this document to present objective facts. Finally, the reader will find a comprehensive list of definitions that are relevant in the field of leak detection at the end of this report.
KROHNE (2012) Principles of Leak Detection