I think it very much depends on the equipment. I think we have multiple tiers of what we support at each type of facility, with traditional data centres having

I think it very much depends on the equipment. I think we have multiple tiers of what we support at each type of facility, with traditional data centres having less stringent requirements (maybe w.r.t noise/filters rather than temp) compared to the facilities housing big routers where -5/55C is the spec to meet. You are right, and it's arguably harder for those smaller boxes sitting in cabinets / on telegraph poles, despite being much lower power systems to start with. It might be 50C+ in there before they even turn on! Those things might have a two-stage boot process where they just run their fans for a bit to cool things down before actually booting the main system. It must be a real nightmare for entirely passive stuff, I have no experience with that.