New Technology – Applied In Place Pipe (AIPP)

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Coating 2″ Pipe

Last summer I spent 3 weeks in Europe investigating new technologies for the drain waste and vent rehabilitation industry. The problem we have with applying our CIPP products to drain, waste and vent piping, primarily inside the building walls, floors and ceilings is multiple tie ins and multiple dimensions. Trying to use a woven or non-woven material to hold resin in place while curing where multiple connections and diameter changes are common is difficult to impossible depending on the pipe orientation.

Over the years several attempts were made to spray on epoxy to the walls of the host pipe, but the efforts to successfully accomplish this were elusive. While several tried coatings that gave the thickness needed for a fully structural repair, the resin tended to pool at the bottom of the pipe leaving little if any on the upper portion of the pipe. Others tried to apply a thin layer of epoxy on the pipe after cleaning it with chain knockers and sand blasting made a nice looking coating, but missed the structural thickness many were looking for in a fully deteriorated pipe. Finally, water trapped inside piping would dilute and render the epoxy worthless if all of the water were not removed prior to coating the pipe. With those challenges in mind, many went to work both in the US and in Europe to solve the problems encountered to produce a fully structural coating to drain, waste and vent pipe found in most households and businesses throughout the world.

After spending several hours on job sites in Europe observing the process and the challenges encountered, we believe we’ve solved all of the problem getting a thick enough fully structural coating on fully cleaned and dried piping that is used in drain, waste and vent piping.

While spraying sounds like the most usable method of delivery, we observed that the thickness varied on turns and direction changes from a spray type application. The inside turns would get a build up of resin while the outside of the turns would be resin thin. Additionally, spraying equipment would plug if the movement of the equipment stopped for any reason during the application of a particular stretch of pipe. Changing spray heads could become a cost issue over time. We found that continuously applying a two part resin to a brush system worked well in both mixing the resin parts and distributing it evenly over all of the pipe wall, even in turns. We even found a solution to clean the brushes between applications for reuse.

The resin of choice in Europe is modified polyurea that has an adjustable cure time between 10 and 30 seconds. With resin that has that fast a cure time, it eliminates the pooling at the bottom of the pipe that epoxy, polyester and vinyl ester resins give. In reviewing the specifications of the polyurea, the type we chose meets the same standards outlined in ASTM F-1216 for cured in place pipe resins. Using the formulas in that ASTM you can determine a design thickness that will provide a structural thickness for a fully deteriorated pipe and apply your coating accordingly.

As with all things, cleaning the host pipe before coating is critical. Also critical is the dryness of the pipe. These are accomplished with all of the tools we currently stock and sell including a heater dryer for the section of pipe that is going to be coated.

We also learned the “art” of applying the product. Allowing too much resin could become a nightmare if it plugged the pipe while applying too little didn’t accomplish a structural pipe that we were looking for. To accomplish the balance between too much and too little, the applicator could adjust flow and apply an initial coating of about 0.5mm thickness. The applicator would watch a televised view of the process as it was going on and would maintain a bead of resin in front of a brush that serves as both a static mixer and a device to spread the resin to the wall of the pipe. If the brush got ahead of the bead, he’d push the brush back and go over the surface again. His equipment would keep track of the quantity of the resin as it was applied and would give the applicator a real time amount of how much was delivered and how much more was left to get the pipe fully coated. This is a very critical part of the process in that it may take 6 or more coats of resin to insure a fully structural pipe was created. If too much build up of material was observed on the CCTV screen, the tech could place a tool on his cable to shave off the excess material. The tech would allow 5 minutes between coatings to insure that the previous coat was fully cured.

Preparation of the hoses that deliver the resin, the camera and the brush tool are taped in an assembly for

a particular section of the pipe you are going to line. We wanted to eliminate disposables as it drove the cost up on the pipe to rehabilitate. We developed a non-disposable hose configuration that allows the resin to flow independently from the pumps to the pipe, a brush that acts as both a static mixer and a simple method to package the resin in disposal inexpensive containers. This cuts costs and provides a great finished product that gives a structural leak proof fix to deteriorated DWV. Call us at 888-354-6464 for more details.

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