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Poly-Butylene Pipes


Poly-Butylene Pipes

Poly-Butylene pipes, also known as Poly-B, is a gray plastic pipe used to supply domestic water and hydronic heating.  This type of pipe was greatly used in the late 1970’s till late 1990’s due to it being cheaper than copper and easy manoeuvrability.  However around the mid-80’s, many Poly-B plumbing systems began to leak.  At first, it seemed to be a problem with the fittings.Many of the fittings used were made of plastic which cracked and leaked over time.In some instances, fittings were installed too tightly and would slowly start to crack leading to leakages.  Water pressure was also a problem as areas with high water pressure could cause a joint to rupture.  And lastly, it turned out that Poly-B pipes had trouble handling hot water and chemicals such as chlorine and began to break down quite quickly.  This made identifying the problem difficult as Poly-B pipes may look fine on the outside but inside they are slowly deteriorating waiting to break open.  Typically, Poly-B plumbing lasts around 10 to 15 years after installation.Poly-B pipes were also used for in floor radiant heating and baseboard heating.Nowadays, Poly-B is no longer approved for new plumbing installations under the National Plumbing Code.  Though it may seem expensive to replace the plumbing and heating in your home, you are actually investing in its resale price.


Poly-Butylene history and information

In the 1980’s thousands of home owners across Canada and the US found themselves in a house full of water leaks.Behind drywall, underneath tiles and in other places you’d never expect, were faulty pipe connections all caused by Poly-Butylene pipe.  Widely used for their cheap price and flexibility, thousands of houses found themselves in similar leaky situations.  This document will outline general information surrounding how to identify Poly-B, where it came from, what happened to it and what is used today.

Poly-Butylene pipes can be found both outside and inside your home.  To identify Poly-B outside, look for your water main.  This is located underground and is usually constructed from ½” or 1” blue Poly-B pipe but may also be gray.  These pipes may be found entering your house through the basement wall or floor, concrete slab or through your crawlspace.  Attached to this pipe should be a shut off valve.  This shut off valve is your building’s main water shut off.  Inside your house Poly-B is typically gray and can be found near water heaters, in unfinished basement ceiling space and exiting walls to feed plumbing and heating fixtures such as sinks and toilets.  In some instances, houses may be equipped with copper “stub outs” where pipes come out of walls to supply a fixture; however this does not mean your house does not have poly.  When looking directly at the Poly-Butylene pipe and depending on where the pipe was cut, you should find words printed on that describe its diameter size, manufacturing and the words “POLY-B”.  If you cannot find this label anywhere then you might not have Poly-B.Poly-B systems can also be identified by the type of fittings used.  Like the pipe itself, the fittings too are made of plastic and are gray in colour but are called Acetal fittings.

Manufactured by Shell in 1970, Poly-Butylene pipes were introduced to the market as a new copper substitute that was light weight and flexible.  Plumbers across North America began using it as it was new and easy to install.  However, it wasn’t until ten years later that homeowners began to experience leaks behind walls, inside ceilings, and even under floor panels.By then, it is estimated that at least one in every four homes were built using Poly-B pipe leading some experts to believe an estimated 6 to 10 million homes contain Poly-B.  Frustrated with their homes slowly turning into water parks, they took action and began to sue.In response, Shell claimed it was the result of poor installation that had lead to leaks.  Mainly, the Acetal fittings, made from a similar by-product of refined petroleum that would often crack and burst due to over tightening.  In response, copper fittings were introduced and more plumbing projects were done and installed with Poly-B.  Though this could have been the case, it does not account for the other problems related to poly-B.For example, many cities use small amounts of chlorine to disinfect drinking water.  However, over time, the small fragments of chlorine build up and deteriorate the inside walls of the Poly-B pipe.  This would lead to broken pipes that would spring leaks behind drywalls.  On top of all this, Poly-B pipes were also known for allowing oxygen to penetrate into boiler systems.  Due to the structure of the pipe surface, oxygen would slowly seep through the walls of the pipe and into the hydronic heating system.  This build up of oxygen in the hydronic recirculation water would cause metal components of the boiler and heating system to rust and plug up.  Thus, both the pipes and boiler would slowly become unusable and in need of replacement.  Though newer models of the Poly-B are said to be coated with an oxygen-barrier coating, they only reduced oxygen permeability to 0.1 grams per cubic meter per day or less.Meaning that oxygen still enters the system, just at a largely reduced rate.  Towards the 1980’s, home owners across both Canada and US were looking to sue Shell.  And in 1995, a class-action law suit was launched in the wake of thousands of claims upon an agreed settlement of $950 million, one of the largest settlements in US history.

Today, pre-existing Poly-Butylene systems must be serviced and altered to include non-ferrous components.As mentioned above, it was due to their manufacturing that pipes would allow penetration of oxygen into the system, often causing rapid corrosion to many metal components.  Even with coated Poly-B pipes, systems were still at risk to oxygen penetration.  Components such as pipes, valves, pumps, and boiler’s heat exchangers would often need replacing and or servicing due to being constantly plugged up with corrosion.  Typically, most components in a boiler system can last up to 30 years; however poly-b systems are known to break down after 3 years.  Pre-existing Poly-B systems can either have their entire system replaced, including pipe and boilers or they can replace their current boiler for one without ferrous metals such as a copper or stainless-steel boiler.  This however does not completely solve the problem.  Though it is more costly to replace the entire system, it can save the building from many other potential leaks and damages.

Alternatively, systems that relied on the benefits of Poly-B such as its flexibility now use PEX pipe.Also known as Poly-ethylene, PEX pipe is manufactured by cross-linking the plastic fibres to maximize structural stability.  They are able to perform all the uses of poly-B pipe without risk of air penetration, internal corrosion and can withstand chlorine.  On top of that, PEX fittings are made of brass therefore are less susceptible to cracking as they are of non-ferrous metals instead of a plastic.

Nowadays, Poly-Butylene pipes are no longer used in installations and have been replaced by Poly-ethylene.Pex pipe is able to compensate for all problems Poly-B pipe suffered from while still maintaining its flexibility.Systems that contain Poly-B are typically replaced entirely.  Suppliers no longer sell Poly-B and so no new buildings are built with it anymore.  If your building currently uses Poly-B then you should look into having it changed to PEX or replace your boiler system with non-ferrous metals such as copper or stainless steel.

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