Authorities are investigating the break of a 66-in. prestressed concrete-cylinder water pipe that flooded busy State Route 190 in Bethesda, Md., on Dec. 23. The pipe, which carries 150,000 gallons per minute, sent water rushing down a nearly half-mile section of the road, stranding more than a dozen vehicles. At least 15 people were plucked from their cars by rescue workers in boats and helicopters.
Ross Contracting Inc., Mount Airy, Md., was awarded a $1.3-million contract by Washington Suburban Sanitary Commission for emergency repairs to the main and several damaged sections of road.
WSSC inspected more than 1,800 ft of pipe near the break and determined that four 16-ft sections need to be replaced. Crews discovered “considerable corrosion of the pipe where the break occurred,” according to a WSSC statement.
The break happened as local temperatures dipped below freezing for the first time this winter.
The pipe was manufactured by now-defunct Interpace Corp. and put into service in 1964. It had a roughly 75-year life expectancy, according to WSSC. In the 1980s, several of Interpace’s pipes that used class-IV wire corroded and prematurely failed. White says the pipe that burst used class-II wire.
Problems with Interpace class II pipe are limited, says Mike Leathers, president of Hanson Pressure Pipe, Las Colinas, Texas. Hanson is providing replacement pipe for the break.
On Dec. 22, Pure Technologies, Columbia, Md., discovered a dozen 96-in. Interpace pipes in a “similar state as the 66-in. pipe that broke,” says Michael Higgins, vice president of Pure Technologies.