introduce
Optical Gas (OGI) thermal imagers utilize spectral wavelength filtering and Stirling cooler cold-temperature filtering to visualize the infrared absorption of gases such as methane (CH4), sulfur hexafluoride (SF6), and carbon dioxide (CO2), as well as refrigerants. FLIR manufactures several thermal imager models, each equipped with a filter that matches the spectral absorption of the gas it is designed to visualize.
Leveraging OGI technology, the oil and gas industry is able to establish safer and more efficient "smart LDAR" (Leak Detection and Repair) programs, enabling inspectors to more quickly detect transient emissions and leaks, immediately identify the source of the leak, and implement repairs, thereby reducing industrial emissions and better complying with legal regulations. Furthermore, optical gas imaging saves costs not only through increased efficiency but, more importantly, through improved safety for company personnel and assets.
To maximize the effectiveness of your OGI device, you should consider the following ten suggestions:
1. Understand the application scenarios and requirements.
Different gas leaks require different thermal imagers for detection. In other words, a single thermal imager may not be able to detect all gases, so the inspector must know exactly what gas is being detected. For example, a VOC/hydrocarbon optical gas thermal imager cannot detect sulfur hexafluoride, and a carbon monoxide optical gas thermal imager cannot detect refrigerants.
2. Consider environmental factors.
The success of optical gas imaging depends on environmental conditions. A greater background energy difference makes it easier for thermal imagers to visualize gas leaks and pinpoint their location. Active optical gas imaging (using laser-based backscattering) relies on the reflective surface of the background. This is particularly pronounced when detecting high-altitude compounds and pointing towards the sky. Rain and strong winds also need to be considered. Rain increases the difficulty of detection, while wind actually aids in gas visualization because it promotes gas movement.
3. Remember: Optical gas imaging is a qualitative, not a quantitative, detection method.
Due to environmental variables, background energy differences, and energy variations, OGI infrared thermal imagers cannot detect the amount or type of gas leaks.
An exception to this basic rule is combining an OGI infrared thermal imager with accompanying technologies such as the QL320 from Providence Photonics. This product (such as the QL320), when used with the FLIRGF320 and FLIRGFx320, can measure mass leakage (lb/h or g/h) or volume leakage (cc/min or L/min) for most hydrocarbons.
4. Fully utilize the functions of the optical gas thermal imager.
Learn how each function of an optical gas imaging thermal imager works, such as automatic GPS tagging or image enhancement features, and utilize these features. Sometimes, even with an optical gas thermal imager, it can be difficult to detect low concentrations of gas. High Sensitivity Mode (HSM) enhances images, enabling the detection of even low gas concentrations. Annotation features (such as GPS tagging) are crucial for ensuring that staff properly repair the correct assets.
5. Measure the temperature correctly.
Many optical gas thermal imagers are temperature-calibrated, making them dual-purpose systems. They are suitable for industrial maintenance inspections because they can measure and record on-site temperatures and save the data as JPEGs or videos. These thermal imagers can be used to detect hot spots or electrical problems in high and low voltage electrical equipment or machinery, or to locate insulation faults in pipes, boilers, etc.
The thermal imaging capabilities of optical gas thermal imagers also help improve the visual contrast between gas clouds and the background scene. Unlike other thermal imaging applications, the object being detected (gas) has no visual representation. Gas clouds can only be seen by rendering a radiative contrast between them and the background. The clouds themselves reflect almost no radiation. The key to making gas clouds visible is to increase the temperature difference (∆T) between the gas cloud and the background.
6. Make full use of the thermal imager's functions to ensure safety.
Gas imaging infrared thermal imagers are rapid, non-contact measuring instruments capable of detecting leaks in hazardous or hard-to-access areas. They are highly sensitive, capable of detecting small leaks from several meters away and large leaks from hundreds of meters away. Many gas imaging infrared thermal imagers offer visual enhancement features (such as HSM) to improve the detection of minute or low-concentration leaks.
Optical gas imaging allows you to detect gas leaks from a safe distance, ensuring your safety. First, perform an initial scan outside the main work area to determine if any large gas leaks are present. Then, gradually move closer to conduct more directional scans. Always wear appropriate safety gear and store and transport the optical gas thermal imager in its accompanying packaging. Regular maintenance of the thermal imager ensures it does not become a safety hazard itself.
7. Must be certified to work.
Overall, OGI thermal imagers are not ATEX certified for Zone 1 locations. Therefore, you will need to apply for a Hot Work Permit or comply with the requirements of a Work Program Permit when using OGI thermal imagers in a Zone 1 location.
The use of OGI thermal imagers in Zone 2 locations also requires a license, with the possible sole exception being the FLIRGFx320—a Zone 2 certified, intrinsically safe, explosion-proof optical gas thermal imager specifically designed for detecting hydrocarbons. Some company guidelines permit the use of this thermal imager in Zone 2 locations without a hot work permit.
Please remember that a top-of-the-line optical gas thermal imager enables you to observe large-scale hazardous gas leaks even in safe areas or beyond the perimeter of the site.
8. Track your return on investment.
In most cases, the cost of an OGI thermal imager is recouped during the initial detection and investigation. Studies show that optical gas thermal imagers are generally nine times faster than traditional leak detection techniques and can help detect leaks that sniffers might miss.
Furthermore, optical gas imaging is a non-contact method that can be performed without interruption of operations, so the company will not lose revenue due to downtime. Moreover, early detection and rapid repair of leaks can help the company avoid fines and retain profitable gas for sale.
9. Carefully consider future industrial emissions regulations.
Escape gas emissions contribute to global warming and pose deadly risks to workers and residents near facilities emitting such gases. FLIR optical gas thermal imagers can detect dozens of volatile organic compounds, such as benzene, thus contributing to a healthier environment while enabling companies to comply with existing industrial emissions regulations. These regulations are not static: government regulatory agencies, such as the U.S. Environmental Protection Agency or the EU Industrial Emissions Directive, are always pushing for stricter regulations on escape emissions. Having the right tools to comply with these regulations helps your company gain a competitive edge.
10. Participate in appropriate training.
Learn from experienced and qualified OGI users to maximize the effectiveness of your thermal imager. You can attend training courses offered by reputable organizations such as the Infrared Training Center ( www.infraredtraining.com ).
The ITC Infrared Training Center's 3-day Optical Gas Imaging Certification Course covers the setup and operation of the FLIRGF series thermal imagers, the types of gases these imagers can detect, and how environmental conditions affect gas leak detection. The training includes classroom instruction and laboratory exercises, and upon completion, participants will receive 2.0 IACET Continuing Education Credits (CEUs).
