The Problem with Epoxy
Epoxy pipe lining, a process involving coating the inside of pipes with an epoxy resin to seal off pinholes and corrosion, is often lauded as a viable alternative to a repipe project. However, while epoxy lining can claim numerous benefits to extending the life of an aging piping system, there are many challenges with the process.
Challenges with Epoxy Lining
In typical epoxy lining applications, the first step is to clean the interior of the pipe. Often times it’s impossible to clean the pipe interior without having a permanent negative structural impact on the pipe itself.
Clients who have previously used epoxy lining as a solution have frequently noted that during the process of cleaning the pipe, pipes are dried, then heated with compressed air, while an abrading agent is pushed through the system via a sand blaster. The epoxy solution is then blasted through the piping system, and coats the interior of the pipe, resulting in a “re-lined” pipe. While this reflects the “typical” lining process, varations occur in the application of the epoxy solution:
Cured In Place
This method includes the insertion of a non-structural material lining often referred to as a “bladder”, which is then coated with some form of epoxy.
Challenges of Epoxy Pipe Lining
- For one, there is no way to know how well the epoxy adhered to the inside of the pipe, and if an even coat was achieved, without cutting into the pipe.
- Second, if a leak occurs at a future date, repairing an epoxy-lined pipe is very difficult. The resin cannot take heat, and application of a torch to try and solder in a new piece of pipe or a fitting ruins the integrity of the lining at that location.
- Likewise, use of a “press-fit” connection (the solution by many epoxy companies for epoxy-lined pipe repairs) may crack the epoxy lining at the point of the repair, allowing water to get between the pipe and the lining, further corroding the pipe.
- The initial epoxy lining process itself creates a certain amount of pressure on the pipe walls, and may blow out at weak spots or threaded areas.
- And lastly, critical elements of the piping system are often excluded in an epoxy lining job.
Does your property have a failed epoxy lined system?
If your property has an epoxy lined system, it’s possible there are sections of the pipe suffering from improper adhesion. Epoxy is permanent. If adhesion fails, properties will find it difficult to make changes, cuts, and repairs, resulting in pipe replacement, which could have been addressed prior to epoxy, without the added cost.
The below examples were taken from a property that was unsuccessfully lined with epoxy just two years ago. As you can see, the lining did not adhere evenly to the inside of the pipe, resulting in settling of the resin at the bottom of the pipe. Likewise, you can see the de-lamination that is occurring on the pipe walls, which may be the result of improper cleaning prior to the installation or an improper installation of the resin itself. Regardless of the cause, the epoxy did not adhere as intended, and corrosion is coming through the lining, causing the installation to fail.
Visit SageWater’s Potable Supply Drinking Water Repipe page for more information about how our One Call Repipe solution works for replacing epoxy lined piping systems.