I can’t remember if this is a myth or for real…but due to the recent tornados (in Maryland) I was wondering about this concept: (this is how I heard it) A tornado will produce extremely low pressure outside your house, the pressure inside your house then becomes much greater in comparision to that and thus burst open the house into flying pieces… So if you leave a window or door open, the pressure inside the house stays relatively the same as the outside pressure; so that, there is no burst of the house. I realize a dead center hit with a tornado - this wouldn’t matter…but is this true for perhaps a near miss?
Neither. The old wives tale says you should open windows, because of the pressure thing, but that’s not true. In fact, if anything, an open window during weak tornados may actually increase damage to your house. In a 250+ mph tornado though, a thin pane of glass makes as much difference as a sheet of paper does to a speeding truck.
The only thing to remember about windows and tornados is to stay the hell away from the former if you are ever caught in the latter.
Sheer piffle. The pressure drop inside a tornado is only about 10%; if you’re far enough away from the tornado to avoid getting your house ventilated by debris, the pressure drop is insignificant. After all, houses have vents built in, which are capable of dealing with pressure changes from thunderstorms & whatnot, as well as distant tornados.
It’s more likely that the open window will let damging winds, debris, water, etc. into the house, causing greater damage than if you’d just left it alone.
Opening windows/doors helps avoid tornado damage about as well as jumping right before impact will help avoid injuries in a falling elevator.
Gives a description of what happens to a house in a tornado, its actually lift generated by air flowing over the house.
However, what if you were to open ALL the windows, yeah stuff would get tossed around but if doing so would give your house another 5-10% (just tossing a number) chance of survivng by undercutting some of the lift effect and reducing wall load since some of the air is flowing through the house rather than around it.
Opening everything you could would almost have to give it a better chance of your house surviving a near miss. Any laminar flow/fluid dynamics experts to help us out around here? Maybe someone who took more physics than me…
The lift would still be acting on the roof, windows up or down. Either way, if your house is close enough to the twister for this to be an issue, it’s gonna be torn apart no matter what you do. Opening windows will do you just as much good as making sure the refrigerator is closed when the twister hits. It just won’t make a difference.
except that this article likens the lift on a house’s roof to the lift on an airplane wing. And then the article relies on the fallacy that an airplane’s lift is solely generated by the motion of air over the top of its wings. which has been thoroughly debunked in this thread
It might also help to consider that the various materials used in constructing houses would react differently if it really were the case that the pressure difference would cause explosive decompression (proper use of the term?). It seems to me that, if a house were completely airtight and you were going to try and explode it, the windows would blow out, since glass is weaker than a house’s walls.
I realize a dead center hit with a tornado - this wouldn’t matter…but is this true for perhaps a near miss?
The above above statement and question mean the same thing, I think you mean near hit.