The left picture was taken with a normal digital camera covering an area of several square kilometers (Different Pictures, original pictures not for publishing) The right one show the same in infrared technology.
When looking at the infrared picture: the entire picture there are similar same temperatures, same colors. The dome of the tanks are a little bit heated up, as well as the top not insulated pipes.
When the entire picture has 70 000 pixels, the small tank in the front right then has 436 pixels, or 20 pixels vertical and 20 pixels horizontal.
If the tank is approximately 12 meters high, then one temperature measurement covers an area of approximately half a meter.
Second example: 320 pixels are covered from left to right, for example cutting the area of all columns. In this case, the smallest column still is covered by two single temperature measurements.
Conclusion: you still are able to detect fire, or steam or any other exceeding temperatures in this whole area.
Such camera detection for example is installed in Norway, overlooking huge areas for early fire detection where no one is living normally or sleeping at night.
In chemical plants such areas are unmanned areas where no personnel shall be there, such as platforms, on and inside structures, flare and other burning pit areas, areas where public sewer systems are below walking areas, detecting leakage of burning media from nearby pipes and vessels, etc. many more application for sure are in your plant as well, saving lots of other conventional equipment, just with one camera.
Personal detection is executed often at airports, when travellers enter the airport building, leaving the plane. On ceilings there are infrared cameras to measure secretly the temperature of invoming perssengers. In case of increasing temperature into fever of a human body, this person will be take out to custonm and health department for checking/returning to their home land.