Los Angeles Is Fighting the UCLA Flood with a Giant Inflatable Pipe Plug

20 million gallons of potable water later, the massive double "trunk line" break that's resulted in spectacular flooding in the streets of Los Angeles and throughout the UCLA campus has finally been sealed off and crews have this bulbous blockage to thank for it.

The water main break, which began Tuesday afternoon along Sunset Boulevard involved the rupture of not one but two high pressure 30 inch-diameter "trunk lines"—the plumbing version of an electricity company's high power transmission lines—right at their junction point. The LADWP first attempted to cut off water to the rupter through conventional upstream valves, however they immediately ran into issues. According to the LADWP:

Water flow into the work area has slowed as LADWP water crews carefully work valves in the area to fully close off water to the site of the rupture. Valves are located near the break and along the two trunklines that connect at the point of a "Y" juncture where the break occurred, and connect to Stone Canyon Reservoir. Closing aged valves that operate at high pressure is a complex operation to ensure additional breaks on the lines do not occur.


When the valves proved ineffective at stopping the leak, LADWP crews turned to a more direct method. They dug down to the rupture and inflated a "balloon" similar to what NYC is developing to halt chemical attacks and flooding in its subway tunnels, which temporarily stopped the flow of water, giving crews a chance to engage the valves and begin patching the ruptured pipe. Up next: draining the flooded UCLA parking garages and beginning damage assessments, which some estimates already put in the hundreds of thousands of dollars. [LA Weekly]

Image: LADWP


This Giant Tube Stopper Will Plug Flooded Subways and Choke Off Gas Attacks

Numerous metropolitan subway systems around the country include spans that pass under bodies of water. If one of those lines were to spring a leak, the resulting flooding could be catastrophic. The Department of Homeland Security might have developed the answer—a giant, inflatable tube plug.

Earlier this year, the DHS Science and Technology Directorate, led by Dr. John Fortune, working in conjunction with teams from Pacific Northwest National Laboratory, West Virginia University (WVU) and ILC Dover, successfully demonstrated the new Resilient Tunnel Project (RTP) system.


The RTP is a large inflatable cylinder 32 feet long and 16 feet wide. It's designed to store in the tunnel's ceiling, then descend and expand to seal that section of tunnel. The plug, filled at 17 to 25 psi, is strong enough to hold 35,000 gallons of water—enough to fill a medium-sized residential swimming pool. Local authorities would be able to remotely activate multiple plugs along the impacted line.

The RTP is constructed of three layers of material. The outermost layer, made of webbed Vectran polymer fiber, provides the overall shape of the plug. The two inner layers are made of solid Vectran and polyurethane, respectively. They are designed to provide the actual seal—not just for the flood waters on the outside, but also the air and/or water used to inflate the device.

"We used the same design and manufacturing techniques we use in space suits and inflatable space habitats," Dave Cadogan, Director of Engineering at ILC Dover, told Physorg. "The webbings and underlying layers form a tough barrier that is strong and resilient."


Since a tunnel's walls aren't perfectly smooth cylinders (they're typically veined with piping and train tracks), the plug is actually designed to expand to slightly larger than the circumference of the tube. It's built with just enough extra material to fill in the gaps, but not so much as to cause the material to fold over itself and permit fluid to leak past.

The plugs can also be deployed to prevent the spread of fires, smoke, or a bioweapon like Sarin gas. They'll be positioned near emergency exits (hopefully ), so disaster victims will be able to quickly evacuate once they reach the stopper. [Physorg - DHS - ILC Dover]