Different schools of thought maybe? When I was in Boca last year, one of the tips that the news people kept repeating was do not open windows or doors to prevent your roof from being torn off. The pressure equalization thing sounds more like a tornado situation.<br><br>
<blockquote><font size=1>In reply to:</font><hr><p>The pressure equalization thing sounds more like a tornado situation.<p><hr></blockquote><p>Living in the heart of Tornado Alley, I grew up opening windows during violent Thunderstorms where Tornado Warnings were issued. The only thing that ever happened by opening windows were wet floors and furniture. <br><br>It was only in my late 20s that I remember watching a tornado documentary on the Discovery Channel which dispelled this myth . . . Here's some info . . . <br><br><blockquote>Myth or Misconception #4 .... Opening windows to equalize air pressure will save a roof, or even a home, from destruction by a tornado.<br><br>The idea that moving one thin pane of glass is going to protect a roof or house from one of the most violent natural forces on the planet has a certain absurdity about it. It is probably born of wishful thinking and faulty logic, stemming from the need to do something .... anything. In reality, opening windows is a dangerous and useless waste of time, and could actually be harmful to the house.<br><br>To get to the very center of a mature tornado (where the pressure may be low enough to cause some explosive effects), the windows would have to endure 100-200 mph winds in the walls of the vortex. Those winds would be laden with boards, stones, cars, trees, telephone poles, and the neighbor's roof shingles as well as wind pressure of more than 100 pounds per square foot. This barrage would blow more than enough ventilation holes in the building to allow any pressure difference to be equalized.<br><br>Even with the windows closed, most houses and commercial buildings have enough openings to vent the pressure difference in the time that it takes for a tornado to pass. The engineering team at Texas Tech's Institute for Disaster Research (Minor et al., 1977) point out that the pressure drop inside a tornado with 260 mph winds is only about 10%, or just 1.4 pounds per square inch. Most buildings can vent this difference through its normal openings in about three seconds. That is sufficient time even if the tornado is moving forward at a very rapid 60 mph. In the real world, the discussion is pointless. That violent a tornado would totally blow apart a house before the central low pressure ever arrived. Venting of air to relieve pressure would not be an issue.<br><br>If the home owner opens the wrong window, air can rush in and exert pressure on the structure from the inside--like blowing air into a balloon. It is unlikely that the resident knows where the construction weak points are. In addition, the wind fields in a passing tornado are very complex and constantly changing. It is not possible to predict the strongest direction of attack. The best advice from every engineer with whom the author has ever discussed this is to leave the windows alone and get into the basement or other shelter as fast as possible. One should not think first of the house roof, but of the impact of one's death on one's family, or of one's self unnecessarily crippled or scarred for life.<br><br>I don't recall the exact origin of the "window opening" advice, but do recall that the original advice was to open windows in both the front and the back of the house. Theoretically, this would allow air to move through the house, and reduce any buildup of interior pressure. Somehow, the advice was altered to include only the windows on the north side of the house, (away from the tornado). There is no evidence that any opening of windows ever helped to hold a roof in place. The best advice is still to forget the windows and get to a shelter.</blockquote><br><br>link<br><br>Then again, my parents had good reason to fear the twisters. They survived the violent Palm Sunday Tornado Outbreak of 1965.<br><br>* * * * * * * * * * * * * *<br>I [censored] bigger than you.<br>
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News People - no wonder, they got it backwards as normal.<br><br>Its with any strong wind.<br>There was a video of Hurricane Ewa back in 82 showing a roof being blown off - when they ran the video in super slow motion the home "expanded" first sorta popped the roof right off the walls and then the wind took it away. <br><br>
Hey Trey good to hear you are ok. You may be seeing some friends of mine very soon. The reports coming out of New Orleans are very bad. The last email I got from our taskforce is that they have been discussing flying rescue squads in helicopters to perform vertacle breaches through roofs to rescue people. From my training I can tell you that, for them to even think about pulling that option out of the trick bag, things have got to be very very bad.<br><br><br>Salus populi suprema lex
Salus populi suprema lex
Loc: Hampstead, MD, USA
<blockquote><font size=1>In reply to:</font><hr><p>one of the tips that the news people kept repeating was do not open windows or doors to prevent your roof from being torn off.<p><hr></blockquote><p>Funny the wives tales that go around, isn't it? <br><br>I find it amazing that people would open or close windows at all. Guess what? The nice curteous tornado or hurricane is going to open it for you anyway! Unless you have a really really good set of heavy duty shutters.<br><br>I remember a study a few years ago finding that homes with garages that survived a tornado often had really heavy expensive garage doors. The ones that didn't had the garage doors blown in, and the wind simply lifts the roof off from below and the house explodes. The ones with the heavy doors stayed intact for the most part, the roof might actually have some of the plywood taken off but the house survived.<br><br>And speaking of power, we were out for nearly 3 weeks when Isabel came through last year. Kind of sucked since we're on a well so we couldn't shower or flush the toilet unless we filled it with store bought water. But I actually found it kind of refreshing as well. It was nice just to come home and sit out in the yard with nothing to do but relax.<br><br>
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