What is Poly B plumbing?
Polybutylene pipe, or its common name, Poly B, is a flexible grey pipe used in residential plumbing and hot water heating systems. Poly B was manufactured from 1978 until 1998 when the resins that the piping was made out of with were discontinued. Although available for quite some time, Ploy B was used more heavily in BC and Canada when residential construction was strong during the 1980’s and the early-to-mid 90’s. Unconfirmed estimates cite that there are in excess of 200,000 homes in BC with Poly-B water systems and some 700,000 homes across Canada that have been affected. Independent reports indicate that Poly B has been installed in more than six million homes during the 80's and early 90's.1 I inspect several homes every month with Poly B piping.
Poly-B supply piping was the first generation plastic piping system that was designed to compete and be a substitute for copper supply piping. The demand for Poly B was driven by escalating copper prices making Poly B pricing attractive, and because it was less labour intensive to install than copper. Here in Canada, Poly B was tested and certified by the Canadian Standards Association (CSA) as an acceptable product for potable water systems. As of 2005, the NRC-CNRC National Plumbing Code does not list Poly B as an acceptable plumbing piping material. NRC-CNRC plumbing codes are not retroactive, so previously acceptable products that are not currently listed still remain acceptable as long as the product does not pose a health/safety hazard.
There are two primary components to the Poly B plumbing system, the grey piping and the connection fittings used to join the pipes.
Poly B plumbing problems
It is important to realize that all plumbing supply systems experience failure. All systems may fail without warning and in some cases cause interior damage, however contributing factors that may cause Poly B failures centre around connection failures, pipe failures, water quality, age, and faulty installation.
Contributing factors that may cause Poly B failures include:
- The use of acetal (grey or white plastic) insert fittings to connect the pipe rather than preferential metal ones.
- Over crimping of aluminum bands that result in hairline cracks in the fittings.
- Poor installation near heat sources, in areas of excessively high temperatures.
- Improper installation that caused stressed piping.
- Applications where relatively high levels of free are used.
The Canadian experience with the two primary Poly B components has been much different than that of consumers in the United States. Consumers in the southern United States have experienced problems due to installation related issues and product performance. Many U.S. failures occurred in southern areas where plumbing was run in attics (a practise not used in Canada) where the piping can be literally baked by excessive heat and in areas with excess chlorine or chemical content. Consumers in BC and Canada had their Poly-B piping installed correctly using copper or brass metal insert fittings and soft copper crimping rings, not the plastic insert fittings with either aluminum or copper bands which are reported to be more susceptible to failure like they used in the States.
Where Poly B has been used with hydronic heating systems instances of oxygen entering the system through the walls of the piping has been reported. The problem here is that oxygenated water circulated through the system can rust out the metal components expeditiously.
For more information on Poly B, home insurance and Poly B, buying a home with Poly B, and what you can do if you have Poly B click here.