In most cases where the air duct is certainly big enough for a small human to get through, that air duct will abruptly start to become narrow or you would run into fans or some other type of obstruction; Also, in a secure facility such as in the films where they have these big air duct systems that are used with some sort of powerful heating and cooling system, it would be likely that they would plan for advanced security measures to prevent intruders as well as pests
Do you ever watch films and shows where people are creeping around through the air duct? I wondered if all of that was even possible. I know the air duct in our little house is flimsy and couldn’t certainly hold a human being, but could it be that the air duct in various facilities is so high quality as well as so large, that it could hold people moving around in it? Well, I was so curious about this subject that I decided to do a little research on it. It turns out that in most cases, this is not really actually possible, at least not the way they do it in the films. In most cases where the air duct is certainly big enough for a small human to get through, that air duct will abruptly start to become narrow or you would run into fans or some other type of obstruction; Also, in a secure facility such as in the films where they have these big air duct systems that are used with some sort of powerful heating and cooling system, it would be likely that they would plan for advanced security measures to prevent intruders as well as pests. I did come across an article that talked about a person who was breaking into stores through the air duct, however he ended up getting caught in there and he ended up suffocating and dying. If anything, a story like that should deter people from trying to enter into buildings through an air duct system. I would be afraid of the heating unit cranking on and burning me up.