The New “Poly”? Cali raises serious questions about PEX piping

by Feb 18, 2020Plumbing

If it’s in your house, you’ll want to read this. In a web site article forwarded to me by a concerned client an organization called the California State Pipe Trades Council (and in conjunction with a slew of other State, safety and health organizations) raised serious concerns and successfully forced a review of PEX piping for environmental, health and durability issues. And as a result, the state has adopted an unprecedented set of restrictions on the use of PEX. The new regulations dictate methods of installation whereby such weaknesses are minimalized such as:

1. PEX pipe vulnerability to permeation by outside contaminants like gasoline or solvents.
2. PEX pipe premature failure when exposed to UV or sunlight.
3. PEX brass fittings failures due to dezincification and stress crack corrosion.
4. PEX pipe potential to fail when installed in continuously recirculating hot water systems.
5. Potential adverse health impact from chemical leaching of methyl tertiary-butyl ether (MTBE).

The PEX Environmental Impact Report (EIR) found that MTBE and tert-Butyl alcohol can leach out from the PEX plastic in amounts that exceed taste, odor and health guidelines set by the State of California for drinking water. The EIR found that PEX pipes can initially leach as much as 290 ppb of MTBE far exceeding the State’s maximum standard of 13ppb.

The EIR also found that outside contaminants like pesticides, oil, gasoline and benzene can permeate through PEX pipe into drinking water. According to the web site, several studies comparing potable water pipe materials including variants of PEX, polybutylene, polypropylene, CPVC, copper and steel have found that PEX, at least initially, “displayed the strongest biofilm formation and the strongest promotion of the growth of Legionella bacteria”.

It’s just not Cali, there are apparently consumer lawsuits in Washington, Nevada, Minnesota, Colorado and numerous other areas across the United States. I could not find any information on a Florida suit. Please let me know if you have heard of any. What I have heard is that there are some insurance companies (big ones) that no longer will cover houses with PEX piping. If this behavior is contagious, it will be huge and will be felt throughout the real estate world.

Apparently some brands of PEX rely on a less stringent ASTM F2023 standard, instead of a tougher NSF P171 standard that other systems benchmark themselves by. The former only assures just more than half the life expectancy of the latter which is about 40 years. To put things into perspective, I read that polybutylene pipe passed ASTM F2023 and we all know the miserable performance history of poly.

Simple exposure of PEX to the sunlight can drastically reduce the ability of the plastic to perform as intended. The report states that even short term exposure to sunlight can dramatically reduce the resistance of PEX to chlorine and result in premature rupture of the pipe. “Studies show just a one-week exposure to sunlight may reduce the chlorine resistance lifetime of some PEX pipes by half; with a two week exposure completely depleting PEX of any chlorine resistance. The susceptibility to sunlight exposure creates a liability risk to contractors and installers because there is almost no way to tell why PEX pipe has prematurely failed or to determine how long PEX pipe has been exposed to sunlight.“

We have all seen exposed PEX at the main water shut off on the side of a house that has been there for years. If two weeks completely depletes PEX’s resistance to chlorine and there is chlorine in all of our water, what then is the life expectancy of years or decades of exposure. We all need now carefully reflect on how we report this to our clients, both agents and inspectors. The client is purpose of our business.

Incidentally, there are some identifiable codes on at least some PEX piping that can determine for us how much exposure that the manufacturer states is acceptable.

PEX is anything but green. Because it is a thermoset plastic, PEX cannot be melted down and reused. Wikipedia defines a thermoset plastic as “Thermoset materials are usually liquid or malleable prior to curing and designed to be molded into their final form… Once hardened a thermoset resin cannot be reheated and melted to be shaped differently. Reheating PEX results in reaching the decomposition temperature before the melting point is obtained. Therefore, a thermoset material cannot be meltedand re-shaped after it is cured. This implies that thermosets cannot be recycled, except as filler material for other products. A 2005 report by the San Francisco Department of the Environment found that PEX was the only type of plastic piping that no plastic recycler would accept. Contrast that to copper pipe which generally contains around 70% recycled material and has almost a 100% recycling rate.

Don’t throw it on the campfire. PEX produces toxic smoke when burned.

How ‘bout house fires.
According to the report, and pursuant to the 2010 settlement agreement, the State of California has approved the use of PEX subject to the following mitigation measures and restrictions: When PEX tubing is placed in soil and is used in potable water systems intended to supply drinking water to fixtures or appliances, the tubing or piping shall be sleeved with a material approved for potable water use in soil or other material that is impermeable to solvents or petroleum products. A pipe in a pipe? This is kinda like cut twice, measure once. It doesn’t make sense. There are other restrictions but not as pertinent to this article but would make the use of PEX very undesirable to any plumber.

This is not the first time PEX has been in trouble. There was the KITEC suit a couple years ago. This sounds reminiscent of generation 1 poly, generation 2 poly, generation 3 poly.

Now armed with new information, you are prepared to make informed decisions. If we all stick together, nobody gets burned!