PEX pipe is a relatively new product for plumbing and heating systems. It is constructed from cross-linked plastic for strength and flexibility. A lot of builders and homeowners like PEX instead of the more rigid materials because it is easier to work with, costs less and lasts a long time.
What Is PEX Pipe?
PEX is short for cross-linked polyethylene. It begins as just regular plastic tubing. Next, manufacturers use heat, chemicals or radiation to connect the molecules of the plastic in a network. This cross-linking process increases the strength of the pipe at elevated temperatures and pressures.
How PEX Is Made
The process of crosslinking polyethylene into PEX is known to have three main systems. And each method impacts the flexibility, cost and utility of the pipe:
1. PEX-A (Peroxide Method)
- Uses peroxide and high heat.
- Produces the most pliable tubing with limited kinking.
- A pick for cramped spaces and tight runs.
2. PEX-B (Silane Method)
- Includes silane molecules and crosslinks with moisture.
- Offers a nice mix of price vs performance.
- Most popular for residential plumbing.
3. PEX-C (Electron-Beam Method)
- Crosslinks using electron beams after extrusion.
- Not as flexible as PEX-A or PEX-B.
- Frequently employed for applications where a mid-level of flexibility can be tolerated.
Color Coding for Easy Use
To eliminate errors, PEX piping is available in three primary colorations:
- Red: Easily identify lines intended for hot water.
- Blue: Indicates lines intended for cold water.
- White or Gray: Can be either Grey/White and is used often in color coding not required situations.
The color-coded feature allows plumbers and homeowners to easily identify the right pipe, reducing the possibility of mistakes during installation and even making repairs.
Key Benefits of PEX Pipe
There are a few very good reasons for choosing PEX in general over traditional metal or hard plastic lines.
- Lower Material Cost: PEX pipe is much more affordable than copper pipe.
- Fewer Fittings: It can reduce elbows and fittings to better maintain water flow.
- Faster Installation: Since it takes less labor time, people pay less for installation.
- Flexible Runs: PEX tubing can twist and turn around walls and through floors without any elbows or couplings.
- Lightweight: One set of coil is easy for one person to carry without heavy lifting.
- Simple Tools: Most fittings can be installed with simple crimp or clamp tools and an open-end wrench.
- Freeze Resistance: PEX can expand slightly when water freezes, which decreases the likelihood of burst pipes.
- Corrosion-Free: It will not rust, pit or scale like a metal pipe.
- Chlorine Tolerance: PEX is prohibited from being damaged by chlorinated water in public water systems.
- Quiet Flow: Water travels more silently and with less “water hammer” through PEX than metal piping.
- Insulating Properties: The plastic wall acts as an insulation and helps hold the water temperature saving energy on hot water systems.
Common Applications of PEX Pipe
PEX tubing is an extremely versatile pipe based on its composition and use. The flexibility, strength, and easy installation make it an ideal product for new construction or remodelling. Here are just a few of the many ways in which PEX can be used:
Residential Water Supply
PEX pipes transport hot and cold drinking water between faucets, showers and other water fixtures in homes. It is rated for potable water and can be used in most building codes, and it functions well in kitchens, bathrooms, and laundry rooms.
Radiant Floor and Wall Heating
When loops of PEX tubing are installed under the floor or in the walls, warm water circulates through these loops, heating spaces uniformly and quietly. The plant may have an energy savings output resulting from the use of reduced water temperatures by the system.
Remodeling and Retrofits
In remodeling projects, PEX can be snaked into existing plumbing with little or no demolition. Plumbers can find PEX through ceilings, walls and floors and connect the tubing to old copper or PVC pipes with transition fittings. This is far less time consuming and messy.
Underground Service Lines
PEX is also used in some water service lines but is not used in the same region of the water service line where it is connected to the water main. It is resistant to corrosion in soil. Pipes are also laid low so they will drain properly.
How to Join PEX Pipe
Seals are critical for a system without leaks. The following three approaches will satisfy the majority of residential and light commercial applications:
1. Crimp Rings
- A copper or stainless steel ring goes over the pipe and fitting.
- When mated, a half-round piston pushes the ring down over the pins, Hogging the hole out and then locking in place.
- Verify the crimp on each connector is within tolerances using a gauging tool.
2. Clamp (Cinching) Method
- A stainless-steel clamp band wraps around the pipe and the fitting.
- A cinch tool applies tension to the band in such a way that it tightens evenly around the pipe.
- Provides a dependable seal and strength on all PEX types.
3. Push-Fit (Expansion) Fittings
- It expands the pipe as it is inserted.
- The pipe now contracts back, squeezing tightly around the fitting.
- No extra rings or clamps are required.
Standards and Building Codes
There are some safety and quality rules to follow for PEX installations so they last a long, and save time:
- ISO 15875: Specifies the requirements for PEX used in hot and cold water supply systems in Europe.
- ASTM F876/F877: Sets forth PEX pipe sizing, pressure ratings and testing in North America.
- CSA B137.5: Canadian standard for PEX tubing and fittings used in plumbing applications.
- Local Plumbing Codes: Always check local plumbing codes for certification requirements, installation practices, and no-lead usage regulations.
Maintenance and Longevity
Properly installed, PEX piping can last 50 years or longer. Key care tips include:
- UV Protection: PEX should be stored and installed out of direct sunlight. Collected UV light can eventually break down the plastic.
- Regular Inspections: Inspect visible runs for wear, damage or signs of leaks at connections.
- Temperature and Pressure Limits: Do not exceed the pipe’s rated 200°F (93 °C) or 160 psi.
- Proper Support: Fasten long runs every 32 inches to avoid sagging and wear.
Conclusion
PEX pipe is cost effective, flexible, durable and easy to install. In many ways, it's better than its conventional counterparts, including easier installation and resistance to freezing and corrosion.
Professionals and amateurs alike can design systems that work dependably for decades when they know the types, benefits, joining methods, and care needs for each. The right choice of PEX, along with its installation and upkeep, helps owners make PEX a top preference in many homes and buildings worldwide.