CHARM® measures the concentration of methane (the main component of natural gas) in the air and detects any traces of released natural gas. In order to identify traces of natural gas, CHARM® uses the property of chemical compounds to absorb light of certain wavelengths. The Differential Absorption LIDAR (DIAL) method is used for this purpose, whereby the system emits two laser pulses of different wavelengths.
CHARM® generates 1000 measurements per second, which are distributed along the pipeline in up to 25 m wide sector. The center axis of the scan sector is called centerline.