I currently work in an L shaped shop and the side branch of the bay is occupied by a machinist who has fitted a wall and sliding door so he can heat his area; we welders keep the bay door open for ventilation.
It made me think of my days as an apprentice welder(resident caveman) in a machine shop. The boss really resented paying to heat the shop and woe to he who opened the door to clear out any fumes or smoke we might have produced. One cold day we opened the door for a few minutes to clear out some smoke and the boss came storming in from his office next door demanding to know why the heat was even on if we were going to need to vent the shop at ANY point during the day. I was new on the job and shaking in my boots. The machinist was working at his bench and without even looking up from his work quietly said that he needed the heat on to hold tolerances. The boss was instantly quiet, did an about turn, and walked away without making another sound. It was such a change in the boss’s demeanor that I had the ridiculous thought that maybe the machinist had incriminating pictures of him!