Installations and pipelines which contain or convey natural gas must be checked regularly to ensure safe and green operation. Checking with hand-held gas detectors is safe and reliable only if the lines and equipment checked are easily accessible and if other site conditions permit.
Conventional hand-held detectors quickly reach their limits, particularly in large-scale and difficult-to-access gas facilities. A real need exists for testers which recognize methane at great distances, therefore making leak detection much easier.
Two technologies are available which offer substantial benefits in these areas: active laser absorption and passive infrared spectroscopy.
Active Laser Detection Technology
This technology senses gas leakage at specific locations. Gas leakage plumes up to a distance of 50 metres are indicated by an acoustic signal. The signal becomes higher-pitched as gas concentration increases - making for easy, operator-friendly gas detection.
Passive Infrared Spectroscopy
This technology visualizes leakage plumes at distances up to 100 metres, even against non-reflective backgrounds such as the sky. The gas plume is shown by colour highlighting on a video display screen.
Advantages and Limitations of Both Technologies
Passive infrared detectors (also known in the industry as gas cameras) are much higher in price than active laser methane detectors. When comparing the two technologies with hand-held instruments and deciding on a solution for a specific application, decision-makers must keep 3 principal considerations in mind:
• Maximization of safety and detection reliability,
• Economics, including purchase investment, costs of labour and auxiliary equipment such as access cranes (required for hand-held devices) and minimization of potential damages as well as downtime,
• Special circumstances or conditions in the intended application which may favor or rule out a specific solution.