Giant plug may help stop mass transit disasters.

• Author: Beidel, Eric
• Position: Defense Technology Newswire

The Department of Homeland Security has combined concepts behind bathtub drain stoppers and space suits to prevent disasters in underground transit systems.

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The DHS Science and Technology Directorate earlier this year successfully tested its resilient tunnel plug, a giant inflatable stopper that can be used to keep gushing water or chemical and biological agents from spreading throughout transit tunnels.

"No one's ever done this before," S&T Project Manager John Fortune said. "It's a completely novel technology."

The plug was developed with the help of Pacific Northwest National Laboratory, West Virginia University and ILC Dover, which makes spacesuits for NASA. It can be filled with water or air in minutes to seal off a section of tunnel and keep flooding under control. It inflates to about 32 feet long and 16 feet wide. It can hold 35,000 gallons, about the same amount as a backyard swimming pool. The plug consists of three layers--a thick webbing made of a liquid-crystal polymer fiber called Vectran, a non-webbed Vectran and polyurethane.

"We used the same design and manufacturing techniques we use in spacesuits and inflatable space habitats," said Dave Cadogan, engineering director at ILC Dover. "The...