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Why Was Polybutylene Pipe Outlawed

In the 1970s and 1980s, polybutylene (also called Poly-B or PB) pipe was commonly used in North American plumbing. PB pipe, made of plastic resin, was popular because it was inexpensive and thought to be durable. 

However, countless homeowners discovered the hard way that the wonder plastic had one major flaw, which led to premature leaks and burst pipes. The extensiveness of the damage throughout North America led to many lawsuits, two of which are infamous and had long-lasting effects on the use of Poly-B pipes.

The mass failure of polybutylene pipes in North American homes resulted in lawsuits being brought against the manufacturers. These suits were settled, but the damage and loss had two major results. Polybutylene pipe was outlawed in Canada. Its sale in the US ceased (but it is not banned in the US).

Polybutylene Is Not Outlawed in America

Even though PB pipe was shown to be faulty, the International Residential Code (IRC) does not prohibit it. Table P2605.1 of the 2021 IRC still lists “PB pipe or tubing” as acceptable piping material.

Polybutylene Is Not Outlawed in America, Illustration of polybutylene pipes

We use the IRC for building regulations in the United States because it serves as an official comprehensive residential code that addresses public health and community safety and serves as a model that can be adapted to local needs. 

The IRC sets up the minimum or baseline code for design and construction to be safe and effective. Using the IRC base system across the country helps to create a consistent residential building standard. 

Manufacturers Do Not Sell to American Markets

Even though it’s not prohibited, polybutylene pipes are no longer used in the United States. This is because manufacturers no longer sell their products in the US to avoid similar lawsuits as those of the mid-1990s (Cox vs. Shell Oil Co. and Spencer vs. Shell Oil Co.) that resulted in the loss of hundreds of millions of dollars for damages and settlements.

The lawsuits came about after many homeowners were experiencing leaks in their pipes that would continuously occur even after being repaired. Consumers filed claims, which built up enough legal momentum to create class-action lawsuits against PB manufacturers. 

The settlement (around 1 billion dollars in the case of Cox vs. Shell Oil Co.) went to replace PB pipe and repair homes that had experienced property damage. The manufacturers are not going to risk such a loss again.

Outlawed in Canada in 2005

In 2005, Poly-B piping was removed from the acceptable plumbing piping material list in the National Plumbing Code of Canada in response to the failure of Poly-B pipes and the various class-action lawsuits in Canada and the US. 

Poly-B piping was removed from the National Plumbing Code of Canada in 2005

As it is against the building code used in Canada, PB pipe can no longer be used. However, changes to building codes are not retroactive, so existing PB pipes in Canada (that were installed before 2005) are still considered compliant with the code if they aren’t posing an active health/safety hazard

Though it is not illegal to have Poly-B pipes, it’s unsafe, costly if they fail, and may prevent insurance coverage or raise insurance premiums. You also have to disclose the presence of these pipes when selling the house, which can put off many buyers.

Why Did Polybutylene Pipes Fail?

Poly-B pipes were initially tested and determined to be useful in potable water systems (Canadian certifiers specified they “should not be used for continuous circulation hot water lines”). However, after being installed, pipes began to degrade, leak, and split, causing major property damage in some cases.

The corrosion of PB pipes was caused by chlorine in the water supply (used to prevent bacteria growth in drinking water). 

Oxidation and chlorine exposure reacted with the plastic, causing deterioration of the polybutylene in the form of chipping and flaking away inside the pipes. This created microfractures that would lead to splitting.

Effects of chlorine in water inside a pipe: chipping and flaking, microfractures and splitting or bursting

Chlorine dioxide, a dissolved gas, can diffuse into polymers like Poly-B, chemically reacting with the plastic and weakening mechanical strength and integrity (this scientific study examined the interaction).

This corrosion inside the pipes meant there was no outward warning of the pipe’s failure, which, in turn, meant that a pipe could burst out of nowhere, causing extreme flood damage. 

PB pipes would degrade in an oxidative environment, typically causing issues within 10-15 years of installation. This is why class-action lawsuits were carried out mainly in 1995, after the popularity boom of PB pipes in the 70s and 80s.

Consequences of Pipe Failure

Pipe failure not only damaged pipes and caused leaks but also caused property damage for many homeowners. 

In the best-case scenario, small leaks can add hundreds of dollars to your monthly water bill in wasted water.

In the worst-case scenario, leaking water soaks into your walls, floors, ceiling, and other parts of the home, damaging the wood and other materials and requiring water damage reclamation service. There are also associated health risks of mold growth or parts of your home collapsing from structural damage.  

The price of Poly-B plumbing replacement depends on several factors: pipe locations, number of sinks, amount of fixtures, number of levels, and general size of the home. The whole process can take a few days to a week. The cost ranges from $5,000 to $7,000 but can reach as high as $15,000.

The pre-determined pipe failure affects homeowner’s insurance.

What Replaced Polybutylene Piping?

Polybutylene piping was replaced by copper piping or more durable plastics such as Cross-linked Polyethylene (PEX (amazon link)) or Polyvinyl chloride (PVC). These materials degrade much slower than Poly-B. 

SharkBite 1/2 Inch x 300 Feet Blue PEX-B, PEX Pipe Flexible Water Tubing for Plumbing, U806B300

Copper piping is the most expensive and durable of the replacement materials. Replacing polybutylene with copper can cost $15,000 or more and can last 50-70 years. 

PEX or PVC piping is less expensive but won’t last as long as copper replacement piping. The average cost can reach $10,000 and the expected lifespan ranges from 30-50 years. 

PEX is the most similar to Poly-B as it is flexible and easy to install, but it is also more sensitive to high temperatures and chlorine content compared with PVC and copper.

PEX Crimp Rings | Will They Work on Polybutylene?


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