The city of Decatur needed to insert a 12-in. valve as part of a pavement removal and resurfacing project.The area where the installation occurred had numerous fast food restaurants, a strip mall and other businesses near it, which would all be affected if the water were turned off.
Time was also a major factor. Between excavating the hole, exposing the pipe and making the repair, the availability of crew workers, the need to issue boil orders and the interruption of service made a conventional shutdown impractical.
The solution
The city of Decatur hired Advanced Valve Technologies (AVT) to install the 12-in. valve from EZ Valve.The complete operation took less then 11⁄2 hours to complete, leaving an AWWA-specified (C-509-01) valve installed under pressure. The city was so impressed with the first installation that it hired AVT to install two more valves several weeks later. Decatur’s water superintendent, Jim Inskeep, called the product the “eighth wonder of the world.”
The second installations involved 6- and 12-in. valves.The main ran parallel through the southeast section of the distribution system, with no valves on either the 6- or 12-in. mains. Furthermore, none of the connecting mains had any valves. In order to make the necessary repairs, the feeder main needed to be shut down, resulting in more than one-third of the city being out of water.
The results
Using the EZ Valve insertion system, both the 6- and 12-in. valves were installed in less than 21⁄2 hours with no disruption of service.
“We [the city] had tried another insertion system several years ago, and we were not impressed,” Inskeep said.“We were surprised to find out that the valve installed did not have the correct number of turns to open and close it. The 12-in. valve required 220 turns—that was not acceptable.”
The EZ Valve insertion equipment uses a unique cutting system. Instead of the traditional method of tapping a size-on-size hole in the main, EZ Valve mills a slot only 15⁄8-in.-wide (to accommodate the valve’s resilient gate) by 120 degrees across the top of the main. The valve does not weaken the pipe’s integrity as other insertion or line stopping systems do. It is rotated during the milling process by a manual feed drive chain. It can then be operated as a standard AWWA valve with the same number of turns.
The EZ Valve, with a 250 psi rating, can be operated with pneumatic, hydraulic or electric power sources. It features an all-ductile iron construction coated to NSF Standard 61 and a resilient wedge gate that is designed to expand and seal the inner diameter of the pipe, regardless of tuberculation buildup.
RSS: Roads & Bridges Articles
