Over the years I have been involved in the infrared industry I have seen some mistakes made and problems missed using spot temperature measurements on IR cameras, luckily these were rectified using the IR software when the reports were written… (would not have been the case had we been using “report by exception” techniques!).
A typical plant is full of equipment that requires periodic infrared (IR) inspection. The challenge, as any thermographer knows, is getting an accurate indication of equipment health. Properly compensating for the various emissivity values of all the components one encounters on the factory floor is possibly the most critical factor in performing accurate and meaningful inspections. Even slight errors in emissivity compensation can lead to significant errors in temperature and Delta T (difference in temperature) calculations. Electrical cabinets are a good example, as they may contain materials with emissivity values ranging from 0.07 to 0.95.
A simple way to check the transmission rate of any infrared window is the “coffee cup test.” Use this test before your initial installation and during regular IR window maintenance for windows with materials that are known to degrade over time.