[Giraffe (He/Him)]

Originally Posted by Mick

One thing most people "know" but never really think about is that you can't see water vapor in air, it is completely invisible. That is why even though there is pretty much always some water vapor in the air around you (humidity), you can't see the air. Let the air drop below the "dew point", and you get fog, which is condensed water vapor.

Back in ancient times when I was a young engineer, we didn't have fancy infra-red detectors like that. If we sprung a high pressure steam leak, you could hear it, but could not see it because it was so hot, it stayed as vapor until it cooled down. So we would hear a steam leak, and the outer portions of the building were fogging up as the steam condensed, buy you couldn't see exactly where the leak was. The common method to finding it is a guy would walk around with a broom stick, and when he saw the end of the stick disappear (because the live steam had sheared it off), that's where the leak was.

Thankfully, in my job, I never had to be the "broomstick guy".

40 year Steamfitter. I'm familiar believe me.