The possible hidden dangers in PEX Pipe
Cross-linked polyethylene tubing has gained ground in residential plumbing systems. Many consumers wonders whether chemicals leach out of the material into drinking water.
Home builders and plumbing contractors have climbed on the PEX bandwagon in droves. Cross-linked polyethylene tubing is increasingly taking the place of copper in residential plumbing systems for a variety of reasons: ease of installation (saves time and money), resistance to acidic water, and the virtual elimination of leak-prone fittings.
While PEX pipe is generally considered safe, in this Best Plumbers Blog post we will address the disadvantages and concerns of PEX pipe.
Dezincification
During the manufacturing process of brass pipe fittings, used to connect the separate sections on PEX pipe, zinc is added to the copper alloy to increase the strength of the brass. Studies have shown that if the zinc levels of brass are too high (generally above 30%), dezincification can occur. Zinc leaches from the brass and creates a powdery buildup. This results in blockage within the fitting, reduced water flow, and leaks. When the zinc leaches from the fitting, the resulting copper becomes porous and weak, which leads to fitting leaks and damage.
Chlorine
Most water in the United States is treated with some level of chlorine in order to disinfect the water supply. It has been found that chlorine can cause oxidation on the inner wall of PEX piping, eventually resulting in failure.
Ultraviolet (UV) Light
As with any plastic pipe, ultraviolet (UV) light can break down the stabilizers in PEX, causing the pipe to become brittle and eventually fail. Overexposure to sunlight prior to installation can result in pipe failure. Most PEX manufacturers allow no more than 60 days of sunlight exposure for normal PEX piping and no more than six months for PEX piping with ultraviolet stabilizers added during manufacturing. Studies have shown a dramatic reduction of chlorine resistance after even one week of direct sun exposure. PEX should not be used in exterior settings or in locations exposed to sunlight.
Permeability
Exposing PEX to certain petroleum products and oxygen increases the permeability of the piping. In closed-loop systems, such as radiant floor heating systems, oxygen can cause heating element corrosion. If PEX piping is installed underground in soils contaminated by pesticides or petroleum products such as methyl tertiary butyl ether (MTBE), these can permeate through the pipe wall and contaminate the water supply.
Chemical Leaching
Potential chemical leaching is another downside of PEX piping. Due to the chemical composition of PEX pipe, the pipe material may leach toxic chemicals including bisphenol (BPA), MTBE, tertiary butyl alcohol (TBA), and others.
Drinking Water Quality
While PEX has passed many water quality tests, there have been studies showing that various brands of PEX piping affect water quality and that it may contain enough material contaminants to affect the smell and taste of water. In order to address concerns about PEX’s impact on water quality, many states, like the State of California, require plumbing contractors to flush PEX piping after installation.
Rodents
There have been instances of damaged PEX piping following the attempt to exterminate rodents. Rodent poison typically causes dehydration, and the sound of water moving through the piping has been known to cause rodents to chew through the PEX to access the water.
Lawsuits
PEX-related lawsuits have involved both the piping itself and the fitting utilized between piping sections. The Kitec® plumbing system manufactured by PEX Inc. and IPEX USA, LLC have been subject to lawsuits. Kitec® piping is typically colored blue for cold water and orange for hot water. Brass pipe fittings used in PEX systems, including those by Uponor, Wirsbo, and Aquapex have been subject to lawsuits due to premature deterioration and leakage.
If you suspect defective PEX pipe or fittings at your home or business contact an experienced plumbing professional from Best Plumbers.