Update: I've had someone come out to see the ventilation, and it seems like it's going to be sorted. They copied me into an email sent to technicians in other schools, and questions were being asked about what needed to be done and why—questions I'd already answered for them multiple times. It sounds like they didn't believe me. This is something that happens quite a bit, and I think it's because I'm younger than most people I work with. I can't complain though; by the sounds of it, some people on here are doing without ventilation entirely, so at least it's getting sorted. I'll update again when it's actually fixed.