THE VIRGINIAN-PILOT
Copyright (c) 1996, Landmark Communications, Inc.
DATE: Thursday, April 11, 1996 TAG: 9604090163
SECTION: NORFOLK COMPASS PAGE: 19 EDITION: FINAL
SOURCE: BY SCOTT McCASKEY, STAFF WRITER
LENGTH: Medium: 56 lines
It may be hard to imagine the city doing extensive underground pipe repair without any digging or major disruption to the surrounding neighborhood.
But thanks to an emerging technology, fixing water and sewer lines under Norfolk's streets is now easier and with much less noise and mess.
Called trench technology or lining, Norfolk is the first city in South Hampton Roads to begin using the method on a large-scale basis. Instead of digging up the street, deteriorating underground pipelines are repaired by threading high-tech plastic tubing from manhole to manhole through existing pipe. Hot water or steam then is forced through the tube, causing the plastic lining to adhere to the pipe, essentially replacing it.
The no-dig approach was applied in Campostella Heights recently and now is ongoing in West Ghent and along Hampton Boulevard.
``The method is just kicking off in this area,'' said Dan Riley, a civil engineer with the Department of Utilities. ``Forms of the technology have been around for several years, but it has recently become more widely used because it has become more cost efficient.''
Riley says trench technology is faster and cheaper because digging inherently is more labor intensive, requiring more machinery, and that the plastic tubing is less expensive than new pipe. One street may be done in a day as opposed to a week with the traditional digging method. The utility department estimates a 40 to 50 percent savings compared to replacing a total line by digging. Expensive street repaving is eliminated.
Lining also is much more resident friendly, taking less time, with minimal traffic detours, blocked roads, and accumulation of mud and dirt.
``It's quicker and less disruptive to the community, and nine times out of 10 more cost effective,'' said Sam Elmore, vice president of Pipelining Products Inc. of Mamaroneck, N.Y., which is doing the work for the city. ``We can get out 350 to 600 feet of street a day instead of 150 with digging.''
Although not exclusively used with lining, TV camera inspection also plays an important part in the technology. Cameras are inserted prior to any work to search for structural problems and afterward to ensure that the pipe is clean and free of blockage.
In some cases, however, old pipe cannot be replaced. In those instances, pipe-busting often is used, which does involve some digging. A cutter is sent through and breaks up the existing line, which is replaced by high-tech plastic tubing. Traditional digging still has to be employed when old pipes have sagged or deteriorated into severe disrepair.
Riley says that the city plans to expand its lining operations, eventually using it for all sewer repair where applicable. Neighborhoods are being studied to determine where the next project is needed most. The lining method was first developed in Europe, where it is used extensively. by CNB