March 11, 2022

By Chad Miller

In the capital city of Helena, Montana, nearly 50 percent of the homes were built more than 80 years ago. The aging sewer laterals that run under the streets – including the tap at the city main – are the sole responsibility of the property owner. Almost all of these sewer drains start as 4-in. cast-iron pipe inside the home, which then transition to 6-in. clay pipe after exiting the foundation.

Because of the City’s history of sewerage back-up issues, Ed Kerins, owner of 3B Rehabilitation Services LLC, was called out to a single-occupancy home built in 1918 and located near the downtown district. The owner had been addressing drainage issues for the past 10 years by having a local service company snake the line. The homeowner repeated this every two years (instead of replacing it) to avoid destroying the beautifully manicured lot with lush landscaping and mature trees.

As if 2021 wasn’t difficult enough for most, the homeowner began noticing another issue – this one being a significant loss in water pressure. After checking with the City, it was determined that this issue was not only on the property owner’s side of the stop box, but it was also her responsibility. A plumbing company was called in to diagnose the problem and found a leak located at the base of her basement steps near the foundation wall. The plumber busted out the concrete floor and rerouted the waterline to exit the west-side of the historic home, around the side of the house, and connect back at the sidewalk. This was done to eliminate the previous line, and required excavation of the front yard.

Now that the waterline was replaced (costing nearly $15,000), the property owner’s ongoing sewer issue resurfaced. When the plumber replaced the waterline, they paid no attention to the sanitary sewer pipe located in the same trench. The property owner’s new issue was sewerage leaking out of the cast iron and filling the hole left open in the basement. She researched sewer repairs and learned of 3B Rehabilitation Services’ trenchless repair option – CIPP lining. Once Ed was called in, he performed a CCTV inspection of the entire pipe. It was then determined that the cast iron was deteriorating through the foundation wall and that the six-inch clay was damaged near the property line during the waterline repair. Apparently, the crew that connected the new waterline to the existing service damaged the clay sewer pipe, then used a piece of 4-in. SDR-35 PVC pipe as a spot repair.

Kerins’s No Dig Team, (a 3B Rehabilitation Services licensee) recently purchased a small diameter lateral lining system and a Picote high-speed drain cleaning machine with tooling from MaxLiner.

“What made the No Dig Team’s initial job so challenging was the need to have a liner that could be installed from inside the confined space of the basement, starting from an existing 4-in. PVC cleanout, transition to 4-in. cast iron pipe, transition to 6-in. VCP, transition back down to 4-in. PVC, then transition back to 6-in. VCP,’ Kerins said. “My newly formed No Dig Team consisted of experienced underground guys with pipe drilling and pipe bursting experience, but not lining experience. We installed two liners that day and felt pretty comfortable, for the most part.

“The next day the crew arrived onsite and began unpacking the lining system from a custom-built trailer. A couple days before, the crew used their Picote high-speed drain cleaning machine to descale the cast iron and remove all the roots that infiltrated most of the clay pipe. The camera was sent down the line to ensure there was nothing in the line and to get the liner measurement. After a light flushing with a garden hose, the pipe was ready for lining.

“The lightweight, all aluminum liner drum was carried down to the basement along with an air hose, and water circulation hoses. Once the equipment was set up, we tested the hot water curing unit and the crew began measuring out the liner, calibration tube, recirculation hose, and pull strap on the sidewalk. Once the liner was measured out and the information was entered into the MaxLiner Mobile App, the liner was put under vacuum and the tube, recirc hose and pull strap were staged in the basement.

“From the app, the resin and hardener were weighed and mixed before impregnating the liner. The entire wet-out process was done inside the trailer and rolled through the electric calibration roller. To gain extra work time, the impregnated liner was rolled into an ice water bath, then transported to the basement. Once the 64-ft liner was rolled into the drum, it was smoothly inverted into the pipe. After we heard the tail of the liner open up we quickly pushed the camera through the inside of the liner to ensure the end was open and we were where we needed to be.

“The camera was extracted, and the 6-in. tube was immediately sent in. Since the drum is equipped with the hose fittings, we were able to begin filling the tube with water as we maintained pressure. Once the tube was fully filled with water and held to pressure, a mobile hot water curing system was turned on to heat and recirculate the heated water. After the return temperature reached 140 F, the resin was cured in an hour and we began the cool down,” concluded Kerins.

After the water and tube were extracted from the line, the liner completely rehabilitated the deteriorated cast iron pipe and immediately transitioned at the 6-in. clay all the way to the end. Using the selected liner enabled the installer the ability to perform transitions and multiple bends up to 90-degrees without having waste.

Source: https://trenchlesstechnology.com/nassco-report-minimizing-disruption-with-a-lateral-cipp-solution/