Thermal Gas Leak Detection Camera for UAV Inspection

Why Gas Detection Requires a Cooled MWIR Detector — Not a Standard LWIR Camera

Standard LWIR thermal cameras (7.5–13.5 μm) detect surface temperature differences through the long-wave infrared thermal emission of solid objects. Most hydrocarbon gases are transparent at LWIR wavelengths — they do not absorb or emit significantly at 7.5–13.5 μm, making them completely invisible to a standard thermal camera regardless of their concentration. Gas detection requires a camera sensitive in the spectral band where the target gas has strong molecular absorption. Methane, propane, butane, benzene, and most hydrocarbons absorb strongly at 3.2–3.4 μm (MWIR). The GIS-320’s cooled InSb detector is specifically sensitive in this 3.2–3.4 μm window, making gas absorption clouds visible as plumes against the background infrared radiation.

The InSb detector must be cooled — typically to cryogenic temperature by an integrated Stirling cooler — because the detector’s own thermal noise at room temperature would overwhelm the small signal contrast produced by a dilute gas plume. The ~10 mK thermal sensitivity achieved by the cooled InSb detector — significantly better than the ≤50 mK of uncooled microbolometers — is what enables the GIS-320 to visualise low-concentration gas plumes that would be undetectable by any uncooled camera technology. This cooled detector sensitivity is the enabling technology for optical gas imaging.

Optical Gas Imaging (OGI) — How Gas Plumes Become Visible

When a hydrocarbon gas cloud is present in the GIS-320’s field of view, the gas layer absorbs some of the 3.2–3.4 μm background infrared radiation that would otherwise reach the detector from the scene background. This absorption creates a detectable contrast difference — the area where the gas is present appears darker (less IR radiation reaching the detector) or brighter (gas emitting IR at its own temperature if warmer than background) relative to the surrounding background, depending on the temperature relationship between the gas and background. The GIS-320 renders this contrast as a visible flowing plume in the real-time thermal image, with the plume’s movement following the gas dispersion pattern driven by the leak pressure and wind direction. Operators can trace the plume back to its source to identify the specific leak point — a valve, flange, compressor seal, or pipeline joint — for targeted repair.

Cooled InSb MWIR Detection — ~10 mK Gas-Specific Sensitivity

The cooled InSb detector’s ~10 mK thermal sensitivity in the 3.2–3.4 μm gas absorption window enables visualisation of low-concentration hydrocarbon gas plumes that are invisible to all uncooled camera technologies. This sensitivity level is the enabling specification for reliable early-stage leak detection before significant gas accumulation occurs — detecting small leaks that pose incremental environmental emission and safety risk before they develop into major incidents.

Real-Time Gas Plume Visualisation at 30 Hz

The 30 Hz frame rate provides smooth, video-rate gas plume visualisation that allows operators to observe real-time plume movement, trace plumes back to their source equipment, and confirm leak source identification during the aerial survey — without the choppy, staccato imaging of lower frame rate cameras that makes plume tracing more difficult. Real-time plume observation during flight enables immediate mission direction: the operator can hover over a detected plume for closer inspection or redirect the UAV for a second pass without waiting for post-flight data analysis.

Purpose-Built UAV Payload — <1.6 kg, MAVLink/SBUS/CAN

At under 1.6 kg and approximately 201 × 150 × 101 mm, the GIS-320 is designed specifically for professional UAV integration on DJI M600 and comparable platforms. MAVLink, SBUS, and CANbus interfaces ensure compatibility with virtually all professional UAV autopilot systems, enabling automated survey mission execution with GPS-geotagged image recording for post-flight geo-referenced gas plume mapping.

10× Optical Zoom Visible Camera for Leak Source Identification

The co-integrated Full HD visible camera with 10× optical zoom provides the equipment-level visual identification needed to convert a gas plume detection into an actionable maintenance work order — identifying the specific valve, flange, or component at the leak source from UAV altitude for immediate maintenance crew dispatch and targeted repair.

LDAR Survey Capability — Wide Area Coverage from UAV Altitude

UAV-mounted GIS-320 surveys cover kilometres of pipeline or large process facility areas in a fraction of the time required for ground-based LDAR inspection using contact sniffers or handheld OGI cameras. GPS geotagging of each inspection frame creates the documented inspection record required by regulatory LDAR reporting programmes, with leak source GPS coordinates and thermal plume images as evidence for each detected emission.

Ground-Based Deployment Option

While designed as a UAV payload, the GIS-320’s compact form also enables deployment on ground inspection vehicles, mobile inspection rigs, and fixed-point monitoring installations for close-range equipment inspection, indoor facility gas monitoring, and continuous fixed-point gas detection at high-risk equipment locations where UAV flight is impractical.

Oil and Gas — Pipeline and Upstream Infrastructure

Aerial LDAR surveys of oil and gas infrastructure are the primary application of the GIS-320 in India, directly relevant to GAIL, ONGC, IOCL, and private upstream and midstream operators:

• Pipeline network aerial LDAR surveys: UAV-mounted GIS-320 surveys of natural gas transmission and distribution pipeline networks covering kilometres per flight, identifying fugitive methane emissions at pipeline joints, valve stations, and regulator sets for LDAR programme compliance and emission inventory reporting
• Compressor station inspection: real-time gas plume visualisation of compressor seals, valve packings, and flange connections at compression stations, identifying emission sources for targeted seal replacement and valve maintenance
• Wellhead and production facility inspection: aerial gas imaging of wellhead Christmas trees, flowline connections, and production separator equipment for fugitive emission detection and regulatory compliance

LNG and Petrochemical Facilities

LNG terminals, refineries, and petrochemical plants handle large volumes of flammable hydrocarbons at high pressures and temperatures, making early leak detection critical for both safety and environmental compliance:

• LNG terminal leak detection: aerial gas imaging inspection of LNG storage tank connections, loading arm flanges, vaporiser equipment, and jetty infrastructure where methane and LNG vapour leaks pose fire and explosion risk
• Refinery unit inspection: gas imaging inspection of distillation column connections, heat exchanger flanges, pump seal areas, and relief valve discharge piping at Indian petroleum refineries for safety and emission management
• Petrochemical plant VOC detection: benzene, toluene, and xylene (BTX) leak detection at petrochemical facilities where aromatic hydrocarbon emissions are subject to strict environmental limits under CPCB and state pollution control board regulations

City Gas Distribution

India’s rapidly expanding city gas distribution (CGD) network — serving Compressed Natural Gas (CNG) and Piped Natural Gas (PNG) consumers across hundreds of cities — presents a large and growing LDAR inspection requirement:

• Urban CGD pipeline surveys: aerial methane leak detection surveys of urban gas distribution networks, CNG station compressor areas, and domestic connection regulators for network integrity management by CGD operators under PNGRB safety regulations
• CNG station inspection: gas imaging inspection of CNG compressor seals, dispenser connections, and storage cascade systems at public CNG fuelling stations for safety assurance and emission management
• Industrial gas consumer connections: inspection of industrial natural gas consumer metering and pressure regulation equipment for leak detection and safety compliance

Environmental Monitoring and Regulatory Compliance

Aerial gas imaging enables quantitative and qualitative emission assessment for regulatory reporting and environmental research:

• Fugitive emission inventory: aerial LDAR surveys generating the documented emission detection records required for MoEFCC and CPCB fugitive emission reporting under India’s environmental compliance framework for oil & gas and petrochemical facilities
• Landfill gas monitoring: aerial methane detection at municipal solid waste landfill sites for landfill gas collection system leak identification and methane emission quantification for GHG inventory reporting
• Agricultural emission research: methane emission monitoring from livestock operations and paddy fields for agricultural GHG emission research at ICAR institutions

Power Generation and Industrial Facilities

Gas-fired power plants and industrial facilities using natural gas as fuel or feedstock require periodic gas leak inspection for safety and efficiency:

• Gas turbine and HRSG inspection: aerial gas imaging of gas turbine fuel supply connections, HRSG duct burner fuel trains, and gas pressure reducing station equipment at combined cycle and open cycle gas power plants
• Industrial boiler and furnace fuel system inspection: gas imaging of industrial boiler fuel supply piping, burner connections, and safety valve discharge areas at factories and process plants using natural gas
• Gas engine power plant inspection: fugitive emission inspection of reciprocating gas engine fuel systems at distributed power generation facilities

United Spectrum Instruments is the official distributor of Workswell thermal imaging products including the GIS-320 in India, providing solution consulting for gas detection application design, system integration with drone platforms, installation and commissioning support, operator training on gas imaging survey technique, and reliable after-sales assistance for oil & gas, chemical, power, and environmental monitoring deployments.

Official Workswell Distributor with Gas Imaging Application Expertise

Official Workswell distributor with gas imaging application expertise — including spectral suitability assessment for target gases, survey protocol design for different facility types (pipeline, compressor station, refinery, LNG terminal), and drone platform integration design for the specific UAVs used by each customer.

LDAR Programme Design and Regulatory Compliance Support

LDAR programme design and regulatory compliance support, advising on survey frequency, flight altitude, wind condition operating limits, GPS documentation requirements, and reporting formats for CPCB, MoEFCC, and PNGRB LDAR compliance needs of Indian oil & gas and petrochemical operators.

Drone Platform Integration Design and Commissioning

Drone platform integration design and commissioning including MAVLink interface setup, gimbal mounting and payload balance calculation, SBUS/CAN connection, autopilot configuration for automated survey mission execution, and GPS geotagging validation for each customer’s specific drone platform.