Why Do CPVC Pipes Turn Brittle?

When CPVC pipes are first manufactured they are highly ductile. You can hit them with a hammer or bend them and they will not break. However, after a short time in service they can become brittle and break like glass - why???  CPVC is tough because it consist of long CPVC molecules which are entangled with each other like spaghetti noodles. However, the pipes lose their strength if the molecules become disentangled from each other. The water pressure inside the pipes are trying to pull the molecules apart but the molecules are locked in place because the pipes are rigid. Exposure of the pipes to certain chemicals cause the CPVC to soften. When this happens, the molecules are no longer locked in place and they start to disentangle from each other causing the pipes to become brittle. Since most hydrocarbon chemicals will absorb into and soften CPVC and there are hydrocarbon chemicals everywhere, it is no wonder why there are so many brittle failures of CPVC piping! For example, I have CPVC drain pipes in my home. One day my wife accidentally spilled a bottle of detergent into the sink. She thought nothing of it and did not flush the detergent through the drain system but allowed it to set in the sink-drain for several hours. The next time she when to use the sink, water flowed from the drain. When I investigated, I discovered that the entire drain system had turned brittle and had to be replaced. Plumbers are becoming aware of this problem and are starting to turn away from using CPVC piping products - see http://www.plumbermag.com/how-to-articles/corporation_lubrizol_pipe_materials/potential_plumbing_problems_lurking_in_walls .

If you have CPVC piping in your building and are concerned. let us know and we will be pleased to investigate to determine if your pipes are becoming brittle.