The installation of IR (infrared) windows, panes, or ports enables thermographers to inspect live electrical equipment without removing protective covers and the resulting exposure to equipment. An arc-resistant window, unlike a port or pane, provides additional protection in the event of an arc flash resulting from unexpected component failures or work on other parts of the system. This substantially reduces hazard ratings and, in most cases, allows the thermographer to work more safely, minimizing the need for excessively bulky and cumbersome protective clothing.
The additional protection afforded by IR windows comes from their being constructed of crystal optic materials designed to better protect the infrared thermographer under an arc-flash condition during inspection of internal equipment.