Optical Gas Imaging

Description:

Optical gas imaging (OGI) uses infrared cameras to visualize gas leaks as visible plumes in real time — allowing operators to detect and locate gas releases from pipelines, valves, flanges, compressors, and storage vessels at safe standoff distances without shutting down equipment or making contact with potentially hazardous components.

OGI cameras use cooled infrared detector arrays that operate in the mid-wave infrared (MWIR) or short-wave infrared (SWIR) spectral band. Specific spectral filter selections match the camera’s detection window to the absorption wavelengths of target gases. Methane and hydrocarbon gases absorb strongly in the 3.2 to 3.4 µm spectral region. SF6 and refrigerant gases absorb in the 8 to 12 µm long-wave infrared region. The camera renders gas absorption as a dark, moving plume visible on screen against the background thermal scene. Furthermore, digital image processing enhances plume contrast — making small or diffuse leaks visible that would appear invisible without signal enhancement algorithms.

FLIR GF Series cameras represent the professional-grade OGI standard. The FLIR GF320 uses a cooled InSb detector at 320×240 pixel resolution operating at 3.2 to 3.4 µm — detecting methane, ethane, propane, butane, benzene, and other hydrocarbons. The FLIR GF306 targets SF6 detection for electrical switchgear inspection. Detection sensitivity on professional OGI cameras reaches parts-per-million per meter (ppm·m) levels — identifying leaks too small and diffuse to trigger fixed-point catalytic or electrochemical sensors between their mounting positions. Additionally, simultaneous visible-light and infrared display modes overlay the gas plume image onto a standard color video image — providing spatial context for accurate leak location identification and documentation.

Radiometric OGI cameras add quantitative temperature measurement to the gas visualization capability — allowing the operator to distinguish gas plumes from steam releases and hot air convection currents that appear similar on standard OGI cameras.

These cameras serve Pakistan’s SSGC and SNGPL gas distribution maintenance programs, OGDCL and PPL upstream processing facilities in Sindh and Balochistan, fertilizer manufacturing plants in Multan and Lahore, LPG terminal operators at Karachi Port, and industrial refrigeration system maintenance contractors requiring non-contact, wide-area gas leak visualization during routine inspection surveys and regulatory emissions audits.