It's great to have a quality thermographic camera and a well-administered thermography program. But what do those images and temperatures really mean?

Certain types of testing are more relative than absolute. Insulation resistance testing is very much that way, thermography mostly that way. For example, does a 170°F reading on a motor vent mean the motor is fine or that it's overheating? How do you know what this reading is really telling you?

The key to making these kinds of tests useful is to establish baseline readings when the equipment is first put in service. These will be your reference for judging whether future readings are abnormal.