Pex pipes have gained popularity in recent years due to their flexibility and resistance to freezing temperatures.
They are made from cross-linked polyethylene (PEX), a type of plastic that is resistant to corrosion and scaling.
Pex pipes are also known for their long lifespan, with some lasting up to 50 years or more.
However, the safety of Pex pipes for drinking water applications has been a topic of debate.
Types of PEX Pipes
There are several types of PEX pipes, each with its own unique characteristics and benefits.
Cross-linked PEX pipes are flexible and resistant to freezing temperatures. They can withstand extreme pressure and are often used for hot and cold water distribution.
Al-RAYAN PEX pipes are made from a type of cross-linked polyethylene and are known for their durability and resistance to corrosion. They are also resistant to scaling and are often used in high-temperature applications.
Other types of PEX pipes include PERT, PE-RT, and PEX-AL-PEX, each with their own specific features and advantages.
Cross-Linked Polyethylene
Cross-Linked Polyethylene (PEX) pipes are a popular choice for plumbing due to their flexibility and resistance to corrosion. They are made from a type of plastic called polyethylene that has been cross-linked to improve its properties.
PEX pipes are joined using a variety of polymer and metal fittings. Unlike other types of plastic pipes, PEX pipes cannot be recycled into new pipes, so their end-of-life options are limited.
Some studies have identified known carcinogens like benzene and the potential endocrine disruptor 2,4-di-tert-butylphenol in water passing through PEX pipes. These chemicals may result from the degradation of antioxidants or other additives used in the pipe manufacturing process.
PEX pipes are susceptible to degradation by UV rays and if exposed to sunlight, the molecular structure disintegrates. This causes the piping to become brittle, rupture, and leach plastic compounds into water.
There are different types of PEX piping, namely PEX-a, PEX-b, and PEX-c. Of the three, PEX-a is considered the most preferable due to the fact that it is the most flexible with no weak links in the molecular chain.
The leaching of chemicals from PEX pipes is a concern, as some studies indicate that more chemicals can leach from PEX than from other types of plastic pipes.
Plastic Types
Plastic pipes have been used for water supply since the 1950's.
During World War II, the expansion of plastic production was argued by industry and politicians as a necessity, leading to the increased use of plastic pipes.
The most popular types of plastic pipes for water are PVC, HDPE, PEX, and CPVC.
These types of plastic pipes have been widely used in the US due to their popularity and availability.
Here are the most common types of plastic pipes used for water supply:
- Polyvinyl chloride (PVC)
- High-density polyethylene (HDPE)
- Cross-linked polyethylene (PEX)
- Chlorinated polyvinyl chloride (CPVC)
Types of PEX Pipes
PEX pipes are made from a type of plastic called polyethylene. This material is inert, meaning it doesn't react with water, and gives water no odor or taste as it flows through PEX tubing.
PEX pipes come in different types, including PEX-A, PEX-B, and PEX-C. These types differ in the way they are connected, with PEX-A being the most common.
PEX pipes are widely used in plumbing due to their flexibility and resistance to corrosion. They are also relatively inexpensive compared to other types of pipes.
Here's a brief overview of the different types of PEX pipes:
Each type of PEX pipe has its own advantages and disadvantages, and the choice of which one to use will depend on the specific needs of the project.
Safety Concerns
Safety concerns surrounding PEX pipes are a topic of ongoing research and debate. Researchers have found 158 compounds in drinking water associated with plastic pipes, and a recent study on PEX discovered highly variable impacts on tap water quality, taste, and smell.
Testing your water for plastic chemicals that may be leaching into your water is the best way to protect yourself. This can be done through in-laboratory water tests, such as Tap Score's SVOC Water Test, which analyzes for a broad range of plastic-related, semi-volatile organic compounds.
Some argue that even tighter regulations on new plastic piping are needed to inspire confidence in their safety. Potential enhanced safety testing could include multi-year real-world water monitoring, additional toxicological data, and evaluation of safety factors like temperature and exposure duration.
Here are some potential health risks associated with plastic pipes:
- There is limited scientific research on the effects of plastic on the quality and safety of drinking water.
- Research into plastic pipes in water has identified at least 158 contaminants as potential leachates.
- Toxic pollutants such as benzene and toluene can permeate certain types of plastic pipes as they age.
- Plastic is a non-renewable resource and is often difficult to recycle.
Plastic Piping Dangers
Research has identified at least 158 contaminants as potential leachates from plastic pipes in water.
These contaminants can include toxic pollutants like benzene and toluene, which can permeate certain types of plastic pipes as they age.
Testing your water for plastic chemicals is the best way to protect yourself from potential health risks.
A recent study on PEX discovered highly variable impacts on tap water quality, taste, and smell.
Some argue for even tighter regulations on new plastic piping to inspire confidence in their safety.
Here are some potential enhanced safety testing ideas:
- Multi-year real-world water monitoring from actively used PEX systems
- Additional toxicological data and risk assessment focused specifically on PEX
- Evaluation of safety factors like temperature, exposure duration, and simulated aging of PEX
- Analysis of PEX formulation differences on safety
- Environmental impact data regarding PEX life cycle, disposal, and recycling considerations
The limited scientific research on plastic pipes in water means we can't confidently argue that plastic should be the material-of-choice for drinking water infrastructure.
Plastic is a non-renewable resource and is often difficult to recycle.
Is Insulated Safe?
Insulated PEX pipe is safe for drinking water applications, meeting international safety standards such as ISO 15875 and ASTM F876/877.
Our PEX B Non-O2 barrier pipes are designed to transport safely both cold and hot water in domestic hot and cold water distribution systems.
These pipes are specifically suited for potable water systems, assuring that the materials used don't emit lethal chemicals into the water.
However, it's essential to note that O2 barrier PEX is not meant for potable water and would be inappropriate in a drinking system.
Using insulated PEX pipe for underground water lines gives added protection to the water supply and prevents outside contamination of the pipe.
The insulation also acts as a barrier against heat loss, ensuring the water contained remains safe and at a constant temperature even with changing weather temperatures outside.
Frequently Asked Questions
What is the safest pipe for drinking water?
For safe drinking water, copper pipes with lead-free joints are a reliable choice, but consider their higher cost and environmental impact.
Where should you not use PEX?
PEX piping is not suitable for high-temperature areas or direct sunlight exposure. It's also not recommended for outdoor plumbing without proper protection
Sources
- https://informed.habitablefuture.org/product-guidance/13-water-pipes
- https://www.greenbuildingadvisor.com/question/pex-tubing
- https://mytapscore.com/blogs/tips-for-taps/is-plastic-piping-safe
- https://www.bignewsnetwork.com/news/274753030/is-insulated-pex-pipe-safe-for-drinking-water-applications
- https://www.ifanfittings.com/is-pex-safe-for-drinking-water/
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