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Poly B, The Failed Plastic Pipe

A common problem found in houses built in the late 80’s or early 90’s is Polybutylene or Poly B piping. Poly B can be identified by it’s grey colour and it is a plastic pipe. It was very popular in that era and is the early prototype of today’s cross linked polyethylene or “Pex” pipe. Due to a bad reputation and numerous class action lawsuits, it is no longer manufactured.

Domestic Water Uses For Poly B

Poly B was most commonly used in domestic water systems. The main problem with it in these systems is that it does not handle high temperatures or high pressures well. We see a lot of leaks at the piping near the hot water tank. As far as high pressure goes, if the home’s pressure reducing valve fails the risk of leaks spreads through out the whole house. It was also used for underground water mains which is always high pressure. There was two types of fittings used with Poly B: copper and plastic. The plastic fittings are even riskier since the grooves on the fittings deteriorate and they will just shoot off. We’ve been to floods were the fittings can easily be pulled out of the pipe by hand.

Hydronic Heating Uses For Poly B

Poly B was also used in radiant heating applications as well. This can be a problem because the piping does not have the barrier on the piping walls that Pex has. This allows air to enter the system. This causes wear and tear on the metallic parts of the system such as pumps, valves and boilers. The water will turn to a black sludge and the system will not work very well.

What To Do About It

There’s only one way to deal with Poly B in a domestic water system and that is to cut it out and re-pipe it in Pex. It’s always best to be proactive and most insurance companies now will not insure homeowners who have Poly B in their house. When it comes to Poly B in a radiant system its a little more tricky because the pipe is inside the concrete. The options are using a boiler, pumps and other components made of metals that are resistant to rust such as pumps with stainless steel impellers or boilers with brazed plate heat exchangers. The piping can also be separated from the boiler with a heat exchanger. There are also some less costly methods like adding air and dirt seperators and adding chemicals to inhibit the rust and sludge.

If you have Poly B in your house and you would like a free consultation contact us at Boundary Bay Mechanical.