I think the confusion is that whether the door is an emergency exit or not, the issue is that the staff would like the door open for fresh air, the manager says no, and is giving the excuse that it’s a fire door and must remain closed…. And to clarify his position, he’s padlocking it shut.
I asked earlier whether there was adequate ventilation…. If not, it’s an HSE issue.
My 17yo daughter is working at a factory for summer and I just found out there’s only 2 toilets… (1 unisex, 1 disabled) for over 50 staff…. So I might be reading up on HSE more than I should recently.