What we do.
Since June 1975, W. Walsh Company has been performing work related to upgrading and rehabilitating the aging water systems for municipalities. W. Walsh has primarily specialized in cleaning and cement mortar lining of existing cast iron municipal water mains. The techniques and methods of this process are governed and guided by AWWA standard C-602 “Cement Mortar Lining of Water Pipelines in Place – 4 in. and Larger”.
The process begins when an Owner of a municipal water system will advertise a contract for cleaning and cement mortar lining of a defined footage of water pipe in their water system. Through the competitive bid process, W. Walsh co. could be named the lowest responsible bidder and awarded a contract to perform the scope of work.
Temporary Bypass Systems
The first phase in cleaning and cement mortar lining projects for distribution water mains is the installation of a complete temporary bypass system to supply customers directly supplied by the main to be rehabilitated with safe drinking water as the work progresses. The bypass system is a complete water system, usually set along the gutter line of the road. Water is usually supplied to the bypass by attaching the bypass to any fire hydrant located beyond the limit of the rehabilitation work. The bypass is installed along the gutter line on both sides of the street. At homeowner’s driveways, the pipe is laid in the gutter and a gravel ramp is installed on both sides of the pipe to allow for access by the homeowner or customers. At larger commercial driveways and intersecting streets the pipe is located in a narrow trench, usually no more than eight inches deep. After installation, the pipe is filled with water from the source hydrant and checked for leakage. Disinfection occurs immediately afterward, in accordance with AWWA Standard – C651 “DISINFECTING WATER MAINS”, (latest revision). Once water samples have been taken and lab verified to demonstrate a clean bypass system, the customers may have their water service hooked onto the bypass system and removed from the main to be rehabilitated.
The houses and buildings are connected to the bypass by a ¾ -inch potable water hose. This hose is run from an outlet on the bypass system to a spigot on the outside of the building or directly to the meter. During the connection the water meter is removed and a second hose is attached to the water service (where the street side of the meter sits). The free end of this second hose is valved off. This allows the connection at the water main to be “blown out” after cleaning and again after lining. This installation of a water feed hose and a “blow back hose” is repeated on each of the customers on the route of the main to be improved. After all of the affected buildings are supplied water from the bypass, the targeted water main can be shut down to perform the cleaning and lining operations.
Cleaning and Lining process
The advantages of cement mortar lining in-place:
- Saves 30% to 90% over replacement
- Extends life of pipe, old or new
- Increases carrying capacity
- Reduces pumping and maintenance costs
- Stops leakage
- Preserves pipe for optimal hydraulic performance
- Eliminates red/brown water
- Raises distribution pressure
- Prevents corrosion in steel and cast iron pipe