Point Repair Project in Cincinnati Nets Significant Savings vs. Open Excavation

The trenchless method of cured-in-place pipe (CIPP) point repair was used earlier this year in Cincinnati, Ohio, to rehabilitate three sections of a private sewer line, resulting in a 20 percent savings vs. using open excavation.

SWS Environmental Service (SWS) of Cincinnati, Ohio has been providing sewer maintenance services in southwest Ohio, northern Kentucky and southeast Indiana since 1977.  In the late 1990s, the industry and technology was evolving at a rapid pace to include other methods for repairing piping systems. The trenchless point or spot repair liner technology was developed from the existing manhole-to-manhole lining processes.

// ** Advertisement ** //

The new markets associated with point repairs were growing and in 2000, SWS partnered with Infrastructure Repair Systems (Infrastructure) of St. Petersburg, Fla. In today’s economic times, clients are looking for maintenance and restoration solutions at a reasonable cost in a short timeframe.

Point RepairAs a result, SWS began repairing aging sewers using Infrastructure’s patented Trenchless Infrastructure Point Repair System. Over the last decade, SWS has installed hundreds of the Infrastructure Point Repairs in the Greater Cincinnati area as a cost-effective way to rehabilitate failing sewer pipe especially in areas where open excavation is not feasible. The Infrastructure Point Repair System results in a final product that is engineer-certified to maintain the structural integrity of the piping system for 100 years.

// ** Advertisement ** //

The Project
Earlier this year, SWS was approached by a local contractor, requesting that a private sewer system be inspected for future acceptance by the City of Cincinnati. The sewer system included approximately 2,000 ft of 8-in. diameter vitrified clay pipe and serviced a large apartment complex built in 1972. During the CCTV inspection, the sewer system was found to have all the usual maintenance issues that would be expected for piping of this age such as buried manholes and accumulated grease and debris. More importantly, SWS found the system to be in good structural condition, with the exception of three defective areas that included infiltration, cracks and broken pipe.

After review of the inspections, it was apparent that something needed to be done to fix these areas before final acceptance by the City would take place. The immediate response by the contractor was that he would excavate and repair the pipe. Upon further review, it became obvious these repairs could not be typical open excavations.

// ** Advertisement ** //

There were other factors to consider that would impact and affect the methodology for repairing this sewer. Specifically, the sewer was about 18 ft deep, was in an area near an apartment building with large, developed trees and was located under a retaining wall. Based on these factors, the estimated price for open excavation pipe repair was in the neighborhood of $36,000. These challenges forced the contractor and property owner to consider other methods for repairing the pipe that would be cost-effective and not upset the surrounding environment. Subsequently, SWS proposed this sewer be repaired using trenchless technology and submitted a recommendation to install the Infrastructure Point Repair liners, a process that is a proven method for rehabilitating pipe without excavating the surrounding area and was a perfect fit for this project.

The benefits of this lining system are numerous, but in this case, lower cost, minimal inconvenience to the residents, no disturbance to the building structures, surrounding trees, retaining wall, traffic and pedestrian flow and a timely installation process were the determining factors.

// ** Advertisement ** //

The SWS proposal included technical specifications regarding the Infrastructure Point Repair System, the recommended length of repair based on the defects identified in the CCTV inspection and the methodology for installation. Specifically, SWS had identified one location with broken pipe, another with heavy groundwater infiltration coming in from a joint, and a third defective area that showed significant cracks and infiltration at a lateral connection. Due to the repair located at the lateral, it was necessary to coordinate and notify the residents of the affected apartment building to minimize flow into the sewer during the installation operation.

The Infrastructure Point Repair System met the criteria for all three of the defective areas. The kits are customized for each repair according to the pipe diameter and the length needed, most commonly up to 15 ft. Unlike other types of lining systems or patches, Infrastructure Point Repairs do not shrink, and can be applied over running inflow, completely stopping the leak. The liners form a watertight mechanical bond to the host pipe with a smooth transition on each end. 

// ** Advertisement ** //

The contractor and the property owner were impressed with the proposal and choose SWS to install three CIPP liner repairs within the 8-in. sanitary sewer servicing the apartment complex. The point repair liner kits were provided by Infrastructure for the following repairs:
1. Leaking/Infiltrating Joint — 3-ft repair
2. Broken/Fractured Pipe — 4-ft repair
3. Cracked pipe with infiltration at lateral — 6-ft repair

Point RepairRehabilitating the Sewer Pipe
Prior to the sectional liner installation, each sewer was cleaned to ensure a successful mechanical bond, forming a watertight seal within the host pipe. The SWS team of certified installers mobilized to the site to begin the pipe repair operation at the various locations. For each point repair, thermosetting epoxy resin was spread onto the felt and fiberglass liner, which was wrapped and secured around an air bladder. The air bladder or carrier is of a flow through design so that bypass pumping is not required and normal flow can be maintained during the curing process.

// ** Advertisement ** //

The carrier was pulled through the pipe using the existing manhole access points and accurately positioned at the repair point using a CCTV camera system. The air bladder was inflated to the appropriate pressure and the curing process began. After the liner cured, the bladder was removed, the lateral was re-instated and a final CCTV inspection was performed. The end product is a highly durable, permanent repair that is actually stronger than the host pipe, and more resistant to cracking and corrosion.

In this case, SWS installed the Infrastructure Point Repair liners and effectively made a permanent, structural repair in the defective areas in a couple of days at about 20 percent of the original estimated excavation price. The owner was pleased with the final results, as well as the intangible benefits and the tremendous savings to his project budget.

// ** Advertisement ** //

Sharon S. Amato is president of SWS Environmental Service Inc., based in Cincinnati, Ohio. 

// ** Advertisement ** //
// ** Advertisement ** //

See Discussion, Leave A Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.