Science in action!
--T

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Inexpensive roof vent could prevent billions of dollars in wind damage
April 28, 2008

Hurricanes often lift the roofs off buildings and expose them to havoc and damaging conditions, even after the worst of the wind has passed. A local roofer, Virginia Tech faculty members from architecture and engineering, and a graduate student have devised an inexpensive vent that can reduce roof uplift on buildings during high winds, even a hurricane.

Low-sloped roof buildings around Wytheville, Va., where Virginia Tech alumnus Chuck Johnson and his brother, Pat Johnson, operate a roofing business, have sprouted foot-high plastic structures that look vaguely like alien technology – a flying saucer connected by three narrow columns to a dome.

The Venturi Vent Technology system could revolutionize the way roofing is done, Johnson said. “We are using physics instead of mechanical fasteners or adhesives. The harder the wind blows, the better it works.”

The physics is the Venturi effect. You know – wind forced through an opening speeds up. Covered porches create a breeze. Winds blow harder through mountain passes and between city buildings. Cars at any speed split the air, so when you crack the car window to get rid of cigarette smoke, the lower pressure outside sucks the smoke out the window.

Sitting at their kitchen table about six years ago, the Johnson brothers asked, “What if we could split the wind blowing over a roof and create a vacuum to suck the roof down instead of up?”

...More

The video clip says it all.

If they put a latched lid on the top portion of the vent you could also use it as a hibatchi while you wait for the power to come back up.

I don't see how generating a vacuum inside those domes does anything to hold the roof down. It just sucks the dome against the roof structure.

If you stuck a bunch of toilet plungers against the roof, it won't help hold the roof down.

Now if they could do something to let the pressure balance out above and below the roof, like vents, it would be less likely to tear off.

Oh wait, they already do that.

I guess there thing could help keep the roofing surface on on a commercial building with a sealed roof surface and a sealed roof deck (doesn't exist), but it won't keep the roof structure from getting blown off. I didn't know commercial roofs had problems in high wind, there's not much to come loose. Many of them are using built-up roofs that are sprayed on, more durable and energy efficient.