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Line Stop Repair Keeps Water Flowing To Customers
By Dan Brooks, PE
Pipe fittings are installed (above) on either side of a valve to enable the line stop (below) to isolate the area for repair.
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Interrupting water service to customers is something that no water utility looks forward to. Yet, it is often a
necessary part of routine maintenance and repair work that keeps a water system operational and reliable.
Water main valves are the primary method used to control the flow of water. Typically, when a water main break occurs
or a repair is needed, the valves on either side of the repair area are shut off so the work can be performed.
Critical parts of a water system, valves require regular maintenance and operation and eventually replacement due to
age or inoperability.
In Garden City, Michigan, six inoperable valves along the City’s 16-inch main transmission line had complicated water
main repairs for several years. Without the ability to use the valves, breaks in the water system required shutting
down water service to two or three blocks at a time for repair work. Concerns were also growing that a break in the
16-inch transmission line would severely impact the supply of water from two meter pits that connect to the City
of Detroit’s system. A valve replacement project was needed to restore the full operability of their water system.
Traditional valve replacement methods require suspending service to all customers located between the valves used to shut
down a main. This shutoff area typically covers a distance of over 1,000 feet. This method also changes the flow of water
in the water main breaking loose mineral deposits and other sediments that can lead to rusty water complaints. In addition,
most shutoffs require closing multiple valves, increasing the chances of breaking other water mains.
An alternative valve replacement method called line stop repair overcomes several limitations of traditional methods. The
line stop method enables repair work to be performed without affecting large areas of the water system. Temporary plugs are
installed just upstream and downstream of the broken valve to isolate it for repair. The need to take customers out of
service is limited or eliminated and water service for emergency needs can be maintained. After the repair is complete,
the temporary plugs are removed restoring the water main’s original flow.
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Based on the City’s desire to expedite the project and minimize further impacts on its residents, Wade Trim engineers
recommended the line stop approach for the City’s valve replacement program. In fall 2006, the City replaced six valves
over a six-week construction period. Wade Trim assisted the City with prequalifying contractors, provided full construction
administration services, and worked with the line stop manufacturer to prepare contract documents.
“Line stopping enabled us to replace our 16-inch valves with minimal impact on residents,” says Jack Barnes, Garden City
DPW Director. “Now our crews can make water main repairs more efficiently.”
Line stop technology has numerous applications for pressurized pipes from making emergency repairs to performing required
maintenance while minimizing service interruptions.
Dan Brooks, PE, is a Project Manager with extensive roadway, water and wastewater systems experience. He provides
day-to-day engineering services and design support to the City of Garden City and other municipalities. He can be reached
in our Taylor, MI, office at 800.482.2864 or dbrooks@wadetrim.com.
Originally published in Innerview Vol. 21, No. 2, 2007
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