Different leak detection techniques are employed to assess the integrity of pipelines over the past few decades. The leak detection systems are diverse and unique to specific pipelines.

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However, leak detection techniques can be classified based on the physical principles that are involved in leak detection. The leak detection technology can be divided into three categories including biological methods, hardware-based methods, and software-based techniques.

The biological methods employ experienced dog handlers or specially trained personnel to locate and detect leaks through visual inspection either through odor or smell. The biological methods are the traditional leak detection techniques, which employ experienced workers who stroll through pipelines searching for patterns that are unusual near the pipeline, scents which could escape through it, as well as listening for sounds produced by the product that escapes from a pipe hole. 

The outcomes of these leak detection techniques are based on the individual's experience and whether leaks develop either prior to or after the inspection. It is however difficult to detect a leak in the H 2.S or an underground pipeline.

Hardware-based methods employ sensors that are built into the hardware to immediately detect the presence of a leak , and help in the detection of leaks. Common devices include Acoustic emission detectors and fiber optic sensors as well as negative pressure detectors. ultrasonic technology, and thermography infrared.