Sniffers are gas detection units that vacuum air samples from equipment to detect the presence of SF6. Both techniques require the leak inspector to be in close proximity to the equipment, which often means excessive climbing and reaching if the equipment is off the ground. A decade ago, Tom McRae, a physicist working at Lawrence Livermore National Laboratory in Livermore, Calif., developed a laser-based detection system to pinpoint fugitive emissions from chemical plants and oil refineries. These so-called GasVue devices emit a wavelength of laser light that will be absorbed by a target gas. An integral infrared camera captures the light reflected from the target and displays it on a screen.
Leaks show up as black.
The GasVue records its findings on videotape. In 1988, McRae left government service, formed Laser Imaging Systems, and received exclusive licensing privileges for the GasVue technology from the U.S. Department of Energy. The first two GasVue cameras were the MG30 and the TG5. The MG30 is a shoulder-mounted device that can be tuned to detect different gases, making it popular with chemical processors such as Union Carbide. It is capable of detecting leaks up to 50 feet away.