Thermography is a tried-and-tested and popular technique for inspecting live, energized electrical equipment. To carry out tests and inspections, the thermographer usually requires a clear line of sight to the equipment. This can prove dangerous, not least because of the hazards posed by arc flashes.
One of the best ways to minimize the risk is by installing an infrared window. An infrared window (IR window) is a data collection point for infrared inspections. It allows an infrared camera or thermal imager a direct view of the equipment without the necessity of the thermographer having to open the panel. Allowing a closed-panel inspection, an IR window eliminates over 99% of arc flash triggers during inspection. Acting as a solid barrier between the thermographer and the live equipment, it provides him a safe working environment.
An IR window helps to follow the standards laid down by the National Fire Protection Association. This authority on fire, electrical and building safety has laid down the standards for electrical safety in the workplace in its NFPA 70E.
Combined with growing awareness on workplace safety, ensuring safety by installing IR windows should be priority for a manufacturer.
While selecting your IR window, it is important to select the right material to transmit infrared radiation safely. While numerous materials can transmit this radiation, ranging from economical film plastics to high-end germanium optics, the most durable among these is crystal. It is crystal, therefore, that is used in infrared windows.
A suitably coated crystal optic can:
- Maintain flexibility of the infrared camera
- Allow visual inspection
- Enable corona inspection
- Provide greater resistance to arc flashes
An additional safety measure to crystal optic material for arc flash protection, which protects the infrared thermographer in case of arc flashes during scheduled, periodic inspection; is to lock security covers. Locking ensures that only trained and authorized personnel can unlock the covers to conduct an inspection. In addition, locking also protects the crystal optic from impacts. Most importantly, it offers further protection from arc flashes.
Installing IR windows in your equipment would ensure lesser damage caused by arc flashes to both people and property and assist in complying with NFPA 70e.