Pittsburgh Suburb Uses CIPP to Address I/I Issues
The Municipality of Penn Hills, Pa., and The Gateway Engineers Inc. recently addressed heavy inflow-and infiltration (I/I) issues of its sanitary sewer system using a ultra violet cured-in-place pipe (CIPP) lining system.
The installer of the Reline America system was Abel Recon of Mountville, Pa., a certified installer of the patented system for Pennsylvania, and northeast Maryland, Delaware, and southern New Jersey.
The project, one of many for the municipality, was aimed at eliminating the heavy infiltration in the sanitary sewer system. The Blue-Tek lining system was a perfect fit for the issues present onsite. With heavy I/I in the pipes, some of the leaks were addressed ahead of the lining by grouting, and in one instance, a CIPP sectional liner. This work was completed by State Pipe Services of Evans City, Pa., which also rehabilitated the manholes with the Strong Seal product.
Addressing the Problem
Once the I/I issue was addressed, Abel Recon went to work on lining the 8- and 10-in. VCP sanitary sewer main. On one section of the 8-in. diameter main, Abel Recon relined the sanitary line in the backyards of several homes with no disturbance to the properties involved. The Blue-Tek lining system uses ultra violet light to cure the liner, and therefore no access to water (fire hydrants, tanker trucks etc.) was required. This process also does not require direct access to the above manhole for the boiler cure truck used in the traditional lining process.
On another 8-in. diameter line, a buried manhole was located and exposed for Abel Recon’s crew to work from. Abel Recon lined the 8-in. diameter sanitary main, with access to the manhole about 50 ft away from the truck with the liner. The residents involved in the project were extremely happy with the ease and speed of the Blue-Tek lining process and the minimal surface disturbance. The Blue-Tek UV CIPP lining can be cured at speeds of up to 10 ft per minute.
The 10-in. diameter sanitary lines presented their own set of issues to deal with during the lining contract. With access to manholes tight, a dry creek bed was the only place to access the upstream manholes. A pathway was cut out of the creek bed to get access for a winch at the upstream manhole. Curing was accomplished from the lowest manhole from which access was possible. A double pull was used on the uppermost lines and approximately 450 lf of liner was cured at once. Bypass pumping was setup for 1,000 lf on the jobsite to the lowest manhole onsite. Even with the bypass in operation, flows from I/I were still at 7 to 10 percent capacity of the pipes. Abel Recon relined the sanitary lines without the use of a pre-liner — traditionally used when heavy I/I is present — because the Blue-Tek lining system uses an inner and outer film to protect the liner from resin loss or contamination due to wash out from infiltration. A slip sheet is installed prior to the liner being pulled in place, to protect the liner from any damage during pull in.
Once in place in the line, the liner is inflated and the light train (the light train is equipped with a camera for inspection purposes) is inserted in the liner. A pre-inspection of the liner before curing is completed with the owner’s representative in the truck, as the light train is pulled from manhole to manhole. This pre-inspection is another option that traditional lining systems do not afford the owner. After pre-inspection is completed, the lights are turned on and curing begins. The whole process is able to be viewed while the cure is taking place at speeds of up to 10 lf per minute. During the curing process, every foot of the liner is monitored by a Quality Tracker System, which is both tamper-proof and has the ability to track the entire process (seven critical aspects continually) with a data logging and retrieval system. This is another aspect unique to the Blue-Tek lining system.
For the Penn Hills project, Abel Recon used the standard 2.8-mm thick liner for the 8-in. diameter lines and 3.5-mm thick liner for the 10-in. diameter lines. These thicknesses are roughly half the normal thickness required for traditional liners. The Blue-Tek UV CIPP liner can be used on pipes diameters from 6 to 48 in. in nearly unlimited wall thicknesses and liner shapes using the ultraviolet light combination curing technology and the unique seamless spirally wound fiberglass liners.
The end result of the Blue-Tek UV CIPP lining was noticed almost immediately, as the dry stream bed used for access to the manholes was actively flowing within hours of the lining process. Monitored flows in the downstream manhole post-lining, show significant reduction in flows, particularly during rain events. The 7 to 10 percent flow that had been present while the bypass pumping was in operation was effectively eliminated from the sanitary sewer system and the flow returned to the creek that it had originated from. This project was a win–win situation for the owner and the Blue-Tek lining system installed by Abel Recon.
Pat Godwin is business development manager for Abel Recon.
