Homebuilders Embrace PEX as the preferred tubing for hot and cold water distribution systems
All on its own, polyethylene (PE) tubing is an excellent product that has the valued benefits of other plastic tubing/piping systems. It’s durable, easy and safe to install, environmentally sound and cost effective. But when PE polymer chains are linked together by a physical or chemical reaction, a transformation happens. The tubing becomes a completely different material. It’s called PEX (polyethylene cross-linked—sometime the acronym XLPE is also used). PEX is like PE on steroids.
Compared to un-linked PE tubing, PEX is superior. It has greater temperature resistance, greater pressure holding capability, tensile strength, corrosion resistance, creep resistance, abrasion resistance, impact strength and chemical resistance.
PEX tubing was used in Europe in the mid 1970s, but wasn’t introduced to North America until 10 years later. There are three distinct methods of manufacturing PEX: Radiation (E-beam), Peroxide (Engel) and Silane. No matter which method a manufacturer uses, all PEX tubing for use in hot and cold potable water distribution systems in North America must comply with ASTM standard F876/F877 and/or CSA B137.5. These standards list, among other things, that PEX tubing must adhere to particular temperature and working pressure ranges, for example, 180°F @ 100 psi. In addition to ASTM standards, PEX tubing meets NSF potable water health and safety requirements.
PEX offers tremendous versatility. Depending on the application, small diameter PEX is available in coil lengths from 100 to 1,200 feet or more, in colors of red, blue, white and natural. There are several types of joining connections, allowing the installer to select the best joining method for a particular installation as well as for crew experience. For fasteners, contractors can select a system of copper crimp rings, or stainless steal clamps or caps with insert fittings of metal or an engineered polymer. Making PEX even more versatile is a system of expansion fittings, which allows the PEX tubing to shrink around the insert fitting. Last but not least, there is a push-fit system that minimizes labor requirements.
So why specify and replace rigid tubing/piping such as copper and steel with PEX? Here are convincing reasons:
Durable
- More corrosion resistant allowing tubing to be directly installed in concrete
- Resistant to electrolysis and poor water quality
- Freeze damage resistance enables pipe wall expansion avoiding costly ruptures
- Water hammer resistance absorbs hydraulic shock in flexible tubing walls
- Excellent chemical resistance
- Resistance to impact
- Less chance of leakage due to fewer joints required
Easy and Safe to Install
- Can be transitioned to other tubing/piping systems
- Lightweight and flexible allowing ease of use
- Connections made quickly using inexpensive joining tools
- No flames or torches used in installation
- Three installation methods: conventional, remote manifold or home run
- Tubing coilability simplifies handling and installation
- Color-coded to easily identify hot and cold water lines
Environmentally Sound
- Doesn’t amplify noise, making operating system more quiet
- Uses less energy in production, shipment and use
- More sanitary, using no fluxes or lead in joining
- Non-toxic and odorless
- Can be recycled into other products
- Life Cycle Assessment is favorable compared to other materials
Cost Effective
- Low purchase price
- Less material price fluctuation
- Less labor to install
- Fewer fittings
- Less on-site theft
- Remote manifold or home run installations cut costs and uses less energy
With so many features and benefits inherent in PEX tubing systems, there are applications for which PEX is becoming the material of choice: hot and cold water distribution systems, hydronic radiant heating systems (recirculation of hot water in flooring, ramps, driveways), radiant cooling (circulate chilled water instead of hot water), municipal water service pipe, turf conditioning, permafrost protection, reverse osmosis, deionized water and residential fire suppression systems.
The next time you are determining what tubing/pipe to use for smaller diameter applications, think PEX, the fastest growing tubing material in the world.
David A. Chasis
Chasis Consulting, Inc.
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