For years, Steve Allen was frustrated by his inability to effectively tackle what he believes is a large potential market for pipeline rehab work: lining vertical stack pipes that are failing in condominium and apartment buildings.

But all that changed when Allen — the owner of Allens Plumbing in Hawaii — learned about the tee liners made by Repiper AB, a Swedish-based company he ran across at a recent Water & Wastewater Equipment, Treatment & Transport (WWETT) Show. (The product is distributed in the U.S. by APEX CIPP Solutions and Pipe Lining Supply.)

“The tee joint (for branch lines off the stack pipe) is the weakest link in vertical pipe lining,” explains Allen, who’s been doing trenchless pipeline rehab since 2000. “We used to cut holes and reinstate vertical lines, but they often leaked, even when cut properly, because there’s a tiny gap between the host-pipe wall and the liner where water can enter.

“As a result, we’ve turned down multiple jobs because we just couldn’t get that part of the vertical lining right. … It wasn’t worth the long-term liability. We wanted 100% coverage without having to take invasive measures and 100% peace of mind that the connections wouldn’t leak.”

A simple process

The Repiper system offers that peace of mind for Allen, who established his business in the city of Kahului on the Hawaiian island of Maui in 1983. The Repiper technology works in much the same way as a conventional cured-in-place sectional point repair. The main difference is the felt T-shaped liner, as its name implies, has a “leg” on it that fits into a branch-line opening in the stack pipe. (The liner can be used in vertical or horizontal applications.)

When an operator inflates the bladder inside the liner, that leg of the tee pops into a branch line and seals tightly against it while the rest of the liner seals against the main host pipe, above and below the branch connection.

After it’s either heat- or steam-cured (Allens Plumbing uses steam), the bladder is deflated and removed, leaving a seamless and sealed tee connection behind.

The key to a watertight seal lies in getting the rest of the liner sections in between the tee liners to properly overlap with the tee liner. Allen says that for vertical applications, his crews typically install a one-story section of vertical liner, stopping below the branch line. The company uses the felt WovoLiner product, made by MaxLiner USA.

Then the work crew installs the Repiper tee liner, making sure that the bottom of it overlaps the MaxLiner liner below it in the host pipe, and lets it cure. Then workers install the next section of felt liner, with the bottom overlapping the top end of the tee liner.

“You just keep overlapping over and over and over, sort of like installing roof shingles,” Allen says. 

Convergence of technologies

Because the branch lines typically are too short to line, Allen instead uses a Quik-Coating System from Pipe Lining Supply to seal them. It’s important to ensure that the polyurea-based resin overlaps the Repiper tee liner, he says.

The company also relies on drain machines from Quadra Plex and Picote Solutions to prep lines for lining, SeeSnake pipeline cameras from RIDGID and Miniflex cameras from Camtronics BV for pre- and post-lining inspections, and Gvision camera monitors from EPL Solutions.

“There’s no one silver bullet that solves every problem,” Allen points out. “The Repiper just puts another arrow in our quiver that we can use in conjunction with other technologies.”

A typical tee-liner installation takes about an hour, which Allen says might sound like a long time but actually is faster than reinstating lines.

Allen is confident enough about the integrity of the Repiper tee liners to give customers a 10-year warranty against failure. “It provides a good finish and it’s seamless, if it’s all overlapped properly. There are no lips or edges: Everything works with the (water) flow.”

Another benefit: If a liner fails, it often requires invasive techniques to access the host pipe and fix the problem. But because the tee-liner installation is such a controlled process, built piece by piece, it minimizes the potential for failure.

“It might eat a little more of your time, but it saves you from the liability (of failures) in the long run.”

In addition, the deflated tee liner is flexible, so it can travel easily through pipe bends, he adds. 

Large potential market

Using the liners required a significant upfront cost — between $10,000 and $15,000 — for buying the many ancillary components required to install the tee liner, including steamers, bladders, hoses, push rods and air bleeders, Allen points out.

On the other hand, a recently completed project in the city of Lahaina on Maui demonstrates the value of the investment. Allens Plumbing won a bid to reline 116 leaking cast iron stack pipes in a 58-unit, two-story condominium complex, built in the 1970s. The revenue from that job more than covered the initial startup costs, he says.

It took five technicians three months to complete the job. “And I wouldn’t have even attempted it without the Repiper technology.”

The project also illustrates why Allen is so bullish on lining stack pipes versus sewer lines. The math is simple: There’s usually only one main sewer line for an apartment building or condo complex, but there are dozens and dozens of stack pipes in even a small condo or apartment complex, he notes.

Moreover, when crews work on a large vertical-lining project, there’s less fuel consumed and decreased truck wear and tear because they’re not driving to multiple jobs every day, he adds.

“I’ve been saying for years that aboveground pipe rehab is the holy grail of plumbing. And with the Repiper technology, it looks like we’ll be stacked up (with projects) for a long time.”