Pipeline spills occur as pipeline infrastructure ages and transport higher volumes of hazardous products. No matter how good operators manage their pipelines, outside forces beyond the control of the operator such as natural disasters or third-party interventions can cause leaks. Some leaks are unavoidable, but fast detection system and efficient response will minimize the consequences, assuring less damage to the environment, property, and people, and protecting the operator’s reputation.
Leak detection technologies divide into two main groups: internal based and external based. This article provides an overview of external based leak detection methods.
The most common external-based leak detection methods include:
- Biological
- Acoustic sensing
- Vapor sensing
- Infrared camera
Biological method
Experienced personnel can detect the effects of a leak in a pipeline. Product escaping from a pipeline can release odors or make noise or change the environment around the leak site. The operator’s personnel can walk the pipeline at intervals to monitor for such changes. Third-parties such as residents or third parties passing by can also detect and report them. It is a good prevention policy to educate the local community around a pipeline on biological detection and on how to contact the operator if someone suspects a leak. A review of the PHMSA database on leak detection shows that many of the leaks were detected and reported by a third party.
Acoustic sensor
A small leak creates a white noise sound that travels through the fluid to the high-performance acoustic sensors upstream and downstream of the monitored section. The main benefits of this method are:
- Detection of existing leaks
- Detection of corrosion leaks as they develop
- Accurate leak location
The effectiveness of this technique depends on the distances between the sensors and the leak location. This method can be affected by ambient noises or the magnitude of the sound generated by the leak. The sensor can be connected to the pipeline or positioned close to it.
Vapor sensor
Vapor sensors can detect gases that escape from a pipeline. This technology can be beneficial in pipelines that carry highly volatile products. The technology can be prone to false leak alarms if other sources of vapor are close to the pipeline.
Infrared camera
Infrared can detect leaks in both gas and liquid pipelines when a leak changes in the temperature around the leak site. Infrared cameras can be permanently installed, handheld, or mounted on vehicles or aircraft.
Introduction to Pipeline Leak Detection is available on Amazon: https://goo.gl/ESvBMK
The book provides a complete overview of pipeline leak detection systems.
Source
Zhang, J., & Twomey, M. (2017). Introduction to Pipeline Leak Detection. Manchester: Atmos International.