Poly-B

Information on Polybutylene Piping

Polybutylene pipe (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 it was discontinued. 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 affecting some 700,000 homes across Canada.

Poly-B supply piping was the first generation plastic piping system designed as a substitute for copper supply piping. Escalating copper prices made Poly B pricing attractive, and because it was less labor 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

All plumbing supply systems experience failure, but some fail prematurely and without warning. Contributing factors that cause premature Poly B failures center around connection failures, pipe failures, water quality, age, and faulty installation.

The factors that cause Poly B failures include:

• Using acetal (grey or white plastic) insert fittings to connect the pipe rather than preferential metal ones.
• Over crimping the aluminum bands that result in hairline cracks in the fittings.
• Poor installation near heat sources, and with excessively high temperatures.
• Improper installation that caused stressed piping.
• Applications with high levels of chlorine used.

The Canadian experience with the two primary Poly B components was much different than the United States consumers. Home owners 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 where the piping was in areas with excess heat and using water with excessive 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. On the other hand, our counterpart in the States used mostly the plastic insert fittings with either aluminum or copper bands which were more susceptible to failure.

Hydronic heating systems using Poly B had instances of oxygen entering the system through the walls of the piping reported. The problem here is that oxygenated water circulated through the system because it rusts out the metal components expeditiously.