Airborne Detection of Gas Leaks from Transmission Pipelines by Using a Laser System Operating in Visual, Near-IR, and Mid-IR Wavelength Bands

An airborne gas detection infrared (IR) system which includes a laser, infrared imager, and video-recorder is described in this paper. The sensitivity of the system to leaks from ground pipelines by the laser channel is about 100 ppm*m at 100 m by methane. The IR thermographic channel plays an auxiliary role and the video channel allows better coordinate positioning of detected gas leaks in conjunction with a built-in GPS device. A demand for efficient gas leak detection instrumentation which is preferably to be mounted on low-flying aircraft such as a helicopter continues to grow worldwide due to an increasing number of gas pipelines and gas installations. IR thermography has been always regarded as an attractive candidate tool for detecting gas leaks due to its unbeatable remote operation principle. IR thermography is typically used in three types of gas detectors: 1) active systems which implement tunable lasers illuminating the ground surface; 2) spectrumsensitive passive IR systems which view the ground surface through gas plumes, and 3) passive IR thermographic systems which monitor temperature variations temperature in leak sites.