Optical gas imaging has become a mainstream high-precision detection method for modern industrial safety and environmental supervision. Relying on advanced infrared technology, professional thermal imaging devices achieve efficient and visual gas leak detection for industrial flammable, toxic, and greenhouse gases. Unlike traditional detection tools with limited accuracy and coverage, infrared gas detection features strong scene adaptability and high sensitivity. It is crucial for industrial practitioners to clarify applicable gas types and infrared band matching principles, as these core parameters determine the detection accuracy and application boundaries of infrared gas imaging systems.
Not all industrial gases can be identified by infrared technology. Only gases with unique infrared spectral absorption peaks can be captured by professional optical gas imaging equipment. Symmetric diatomic gases, including oxygen, nitrogen, and hydrogen, have no infrared absorption characteristics and are undetectable via thermal imaging. In actual industrial scenarios, detectable gases covered by mainstream infrared gas leak detection services are mainly divided into four categories, covering most common industrial leakage risks.
The first category refers to hydrocarbon combustible gases, including methane, ethane, propane, ethylene, butane, and gasoline volatile gases. These gases feature stable C-H bond infrared absorption characteristics, serving as the core detection targets for oil and gas and petrochemical industries. The second category is industrial special insulating gases, represented by sulfur hexafluoride (SF6). As a exclusive insulating and arc-extinguishing medium for power equipment, SF6 has prominent infrared absorption features, enabling ultra-high recognition accuracy in infrared detection. The third category covers refrigeration and chemical medium gases, such as ammonia and various freon refrigerants and halocarbons, which are widely used in cold chain operation, chemical production, and HVAC system maintenance. The fourth category includes volatile organic compounds (VOCs), namely benzene, toluene, xylene, ethanol, formaldehyde, and hundreds of other organic gases, supporting refined environmental monitoring and exhaust emission compliance inspection.
Detection waveband matching is the core factor that determines the precision of optical gas imaging. Industrial infrared gas leak detection systems are mainly divided into medium-wave and long-wave infrared detection windows, equipped with customized narrowband filter lenses to achieve targeted identification of specific gases.
The medium-wave infrared band (3.2～5.0µm) is known as the golden detection window for hydrocarbon gases. Its core spectral range of 3.2～3.5µm perfectly matches the characteristic absorption interval of hydrocarbon bonds. This band is applicable to almost all combustible hydrocarbon gases and VOCs, including methane, ethylene, propane, benzene series, alcohols, and aldehydes. It is widely deployed in petroleum exploitation, chemical processing, coal chemical industry, and environmental VOCs monitoring scenarios. Most industrial cooled infrared detection devices adopt medium-wave infrared technology, delivering outstanding advantages in high sensitivity and strong anti-interference capability for complex industrial environments.
The long-wave infrared band (10.0～11.0µm) is tailored for special industrial gas detection, with a core precise detection wavelength of 10.6μm. This exclusive spectral absorption window is highly targeted for sulfur hexafluoride (SF6), ammonia, and freon refrigerants. Most long-wave infrared devices are uncooled thermal modules, featuring simple structure and low comprehensive cost. They are widely applied in refined scenarios such as SF6 insulation equipment inspection for power systems and refrigerant leakage detection for refrigeration equipment, with excellent practicability and stability.
As a non-contact, full-coverage, and visualized detection solution,infrared technology has completely upgraded traditional industrial gas leak detection modes. Through accurate matching between infrared spectral bands and gas absorption characteristics, optical gas imaging systems realize targeted detection of combustible hydrocarbon gases, power special insulating gases, refrigeration media, and VOCs pollutants. With the continuous iteration of infrared detectors and spectral filtering technology, infrared gas imaging will develop toward miniaturization and intelligence, providing reliable technical support for industrial safety production, energy conservation, and green low-carbon transformation.