PEX Information – Everything you need to know about PEX Plumbing

What Is a PEX Pipe?

PEX (or crosslinked polyethylene) is part of a water supply piping system that has several advantages over metal pipe (copper, iron, lead) or rigid plastic pipe (PVC, CPVC, ABS) systems.

It is flexible, resistant to scale and chlorine, doesn’t corrode or develop pinholes, is faster to install than metal or rigid plastic, and has fewer connections and fittings.

PEX tubing is made from crosslinked HDPE (high-density polyethylene) polymer.

The HDPE is melted and continuously extruded into the tube. The crosslinking of the HDPE is accomplished in one of three different methods.

PEX plumbing has been in use in Europe since about 1970 and was introduced in the U.S. around 1980.

The use of PEX has been increasing ever since, replacing a copper pipe in many applications, especially radiant heating systems installed in the slab under floors or walkways.

Interest in PEX for hot and cold water plumbing has increased recently in the United States.

Additional Information on PEX Plumbing

1. Types of PEX and Their Applications

PEX comes in different types that are suited for various applications:

• PEX-A: The most flexible type, best for tight spaces and cold climates where expansion is needed.
• PEX-B: More rigid than PEX-A, but highly durable and widely used for residential plumbing.
• PEX-C: The most affordable option, but less flexible and more prone to kinking.
• PEX-Al-PEX: Features an aluminum layer for added durability and shape retention, ideal for high-temperature applications.

Each type of PEX is best suited for different applications:

PEX Type	Flexibility	Durability	Best Used For	Other Notes
PEX-A	Most flexible	High	Residential plumbing, cold climates, and places needing expansion	Expands to resist freezing
PEX-B	Less flexible than PEX-A	Very high	General residential and commercial plumbing	Strong resistance to chlorine and oxidation
PEX-C	Least flexible	Moderate	Budget-friendly projects where bending isn’t required	More prone to kinking
PEX-Al-PEX	Rigid	Very high	High-temp applications, radiant heating, and municipal water systems	Aluminum core helps it maintain shape

2. PEX vs. Other Plumbing Materials

A comparison table showcasing the differences:

Feature	PEX	Copper	PVC/CPVC
Cost	Lower	Higher	Lower
Flexibility	High	None	Low
Corrosion Resistance	Excellent	Prone to corrosion	Excellent
Installation Ease	Easy (fewer fittings, no soldering)	Hard (requires soldering)	Moderate (gluing required)
Freeze Resistance	Excellent	Poor	Moderate
Lifespan	40-50 years	50+ years	25-40 years
Noise Reduction	Quiet	Can be noisy	Quiet

PEX tubing is quieter than copper pipes, as it does not create “water hammer” noise when valves are shut off quickly.

Advantages of PEX Plumbing

Flexible PEX tube is manufactured by extrusion and shipped and stored on spools, where rigid plastic or metal piping must be cut to some practical length for shipping and storage. This leads to several advantages, including lower shipping and handling costs due to decreased weight and improved storage options.

PEX plumbing installations require fewer fittings than rigid piping. The flexible tubing can turn 90-degree corners without the need for elbow fittings, and PEX tubing unrolled from spools can be installed in long runs without the need for coupling fittings.

Attaching the PEX tube to fittings does not require soldering and so eliminates the health hazards involved with lead-based solder and acid fluxes; PEX is also safer to install since a torch is not needed to make connections.

PEX resists the scale build-up common with copper pipe and does not pit or corrode when exposed to acidic water.

PEX is much more resistant to freeze-breakage than copper or rigid plastic pipe.

PEX tubing does not transfer heat as readily as copper and so conserves energy.

PEX plumbing installations cost less because:

• PEX is less expensive than copper pipe.
• Less time is spent running pipe and installing fittings than with rigid pipe systems.
• Installing fewer fittings reduces the chances of expensive callbacks.
• PEX requires fewer tools than copper installation.

PEX Tubing

The terms PEX pipe and PEX tube have been used interchangeably, however, some manufacturers distinguish between the two by manufacturing to different inside/outside diameters.

For example, PEX pipe may be manufactured to IPS-ID (iron pipe size, inside diameter, controlled) sizes with varying thickness to meet pressure requirements, while PEX tube may be manufactured to CTS-OD (copper tubing size, outside diameter controlled) sizes, commonly with a standard thickness of SDR-9 (standard dimension ratio).

The PEX tube manufactured to CTS-OD sizes is the most common, with available sizes including 3/8″, 1/2″, 5/8″, 3/4″ and 1″. On this website, “PEX tube” refers to this common CTS-OD product.

Before extrusion, the HDPE can be pigmented to yield color-coded pipe.

PEX tubing can be:

• “Natural” (hazy clear, unpigmented)
• White
• Black
• Red (hot water)
• Blue (cold water)

The red and blue colors are used to help plumbers and homeowners distinguish between hot and cold-water supply lines. The tube will be marked outside to show which standards it meets.

As it is produced, PEX is wound onto spools for storage and shipping. A typical spool of 1/2 inch PEX will hold 1200 feet of tubing.

PEX Tubing Compatibility

Most PEX tubing is compatible with all the various connection methods, with PEX-Al-PEX being the exception.

			Compatible PEX Connections
PEX Tubing Manufacturer	PEX Product Name	Tubing Type	Standard Crimp Ring	SSC (Stainless Steel Clamp)	Proprietary Connection Types	Compression Fittings
IPEX	Kitec XPA	PEX-Al-PEX	✔	✔		✔
IPEX	CTS SDR9 PEX Tubing	PEX	✔	✔	✔	✔
Rehau	RAUPEX®	PEX	✔	✔	✔	✔
Upanor / Wirsbo	Wirsbo AquaPEX®	PEX	✔	✔	✔	✔
Vanguard	Vanex	PEX	✔	✔	✔	✔
Vanguard	COMPAX-L	PEX-Al-PEX	✔	✔		✔
Viega	Pexcel	PEX	✔	✔	✔	✔
Viega	FostaPex	PEX-Al-PEX	✔	✔		✔
Viega	Pextron (Oxygen Barrier)	PEX	✔	✔	✔	✔
Weil-McLain	Qual-Pex (Oxygen Barrier)	PEX	✔	✔	✔	✔
Weil-McLain	AlumiPex	PEX-Al-PEX	✔	✔		✔
Zurn	Zurn PEX (Non Barrier)	PEX	✔	✔	✔	✔
Zurn	Zurn PEX (Oxygen Barrier)	PEX	✔	✔	✔	✔

How To Connect PEX Pipe

1. Standard Connection Method

The standard method for connecting PEX pipe to brass PEX fittings uses a copper crimp ring and a PEX crimping tool.

1. A copper crimp ring is inserted over the PEX pipe.
2. The fitting is inserted inside the pipe.
3. The crimping tool is used to compress the copper ring, securing the pipe to the fitting.

✅ Pros: Reliable, widely used, compatible with many systems.
❌ Cons: Requires a dedicated crimping tool, risk of over- or under-crimping.

🔹 Best for: General plumbing applications, hot and cold-water supply.

Tools, fittings, and crimp rings are available from several suppliers. Information about testing standards for this method can be found on the ASTM standards page.

2. Expansion Fitting Method

The expansion method involves using an expansion tool to temporarily increase the diameter of the PEX tube.

1. A PEX expansion tool is used to stretch the PEX pipe.
2. A special expansion fitting is inserted into the expanded tube.
3. The pipe naturally shrinks back to its original shape, forming a secure connection.
4. A reinforcement ring is pressed over the fitting to ensure a tight seal.

✅ Pros: No risk of crimp failure, allows natural expansion/contraction.
❌ Cons: Requires a specialized expansion tool, limited brand compatibility.

🔹 Best for: Cold-weather installations, areas prone to pipe expansion/contraction.

This method was developed as a proprietary solution and is currently available from one company. Information about testing standards for this method can be found on the ASTM standards page.

3. SSC (Stainless Steel Clamp) Method

The SSC method uses stainless steel clamps designed for PEX connection.

1. A stainless-steel clamp is placed over the PEX pipe.
2. The fitting is inserted into the pipe.
3. A SSC crimping tool is used to tighten the clamp, securing the connection.

✅ Pros: Requires only one tool, easy to adjust before tightening.
❌ Cons: Slightly bulkier than copper crimp rings, requires precision clamping.

🔹 Best for: DIY installations, repairs, and areas where crimping tools aren’t available.

The fittings used here are the same as in the Standard Connection Method, but instead of a copper ring, a stainless steel clamp secures the fitting. Information about testing standards for this method can be found on the ASTM standards page.

4. Compression Method

Standard compression fittings can be used to make connections between PEX tubing.

1. A compression ring (ferrule) is placed over the pipe.
2. A compression nut is tightened onto the fitting, compressing the ferrule and sealing the connection.

✅ Pros: No special tools required, removable and reusable.
❌ Cons: More expensive than crimping or clamping methods, bulkier fittings.

🔹 Best for: Transitioning from PEX to copper, temporary or removable installations.

For moderate to large-sized jobs, this method is more expensive than using the Standard Connection Method, since compression fittings cost more than PEX fittings.

5. “Push-Fit” and Other Proprietary Methods

Several companies offer specialized fittings that will connect PEX to PEX, copper, PVC, and other materials.

These fittings use one or more of several technologies, such as:

• EPDM O-ring seals for watertight connections.
• Stainless steel gripping teeth to secure the pipe in place.
• Threaded compression nuts for added stability.

✅ Pros: Quickest installation method, no tools required, works with multiple pipe materials.
❌ Cons: More expensive per fitting than standard PEX fittings.

🔹 Best for: Emergency repairs, retrofits, quick installations without specialized tools.

These fittings are faster and easier than most competing methods but cost more per fitting than standard PEX fittings.

PEX Fittings

PEX fittings are generally made of brass, although some vendors are offering bronze, copper and engineered plastic fittings for PEX. The characteristic ridges on the “insert” part of the fitting distinguish a PEX fitting from other fittings (see pictures below).

The ridges, the PEX tube, and the crimped copper ring all work together to form a high-pressure seal.

Adapter: PEX (top) to polybutylene	Adapter: PEX (top) to MIP	Adapter: PEX (top) to copper (sweat)

PEX Fittings Compatibility

The Standard Crimp Ring method is the most popular way to connect PEX tubing. The fittings listed under the Proprietary Connection Type column are unique to specific manufacturers and often require specialized tools. Most of these are not compatible with other PEX connection methods.

• Standard PEX fittings can be used with the Standard Crimp Ring and SSC (clamp) method.
• Compression fittings can be used to make connections with PEX tubing but do not use standard PEX fittings.
• Proprietary connection types require manufacturer-specific fittings and tools, limiting cross-compatibility.

PEX Tools

To work with PEX tubing using the standard crimping method, three basic tools are needed: the main crimping tool(s), a pipe cutter, and a de-crimping tool.

1. Pipe Cutter

• The pipe cutter is used to make a clean, square cut before inserting the tubing into the fitting.
• A PEX-specific pipe cutter ensures a smooth cut, preventing rough edges that could impact the connection.
• Tip: Always rotate the cutter evenly around the pipe to avoid an uneven cut.

2. Crimping Tool

• The main crimping tool can be purchased in several configurations from various vendors.
• One popular model has the capability to crimp either 1/2″ or 3/4″ PEX tube, while another uses interchangeable crimp heads to work with any PEX tube sizes.
• Alternative tools: Some manufacturers offer ratcheting crimping tools that provide better leverage for easier crimping.

3. De-Crimping Tool

• A de-crimping tool is designed to remove the copper crimp ring from the tube and fitting.
• Various designs all work by cutting the copper ring.
• Fittings can be easily re-used if they are not damaged.
• Tip: Some models have built-in cutting guides to prevent damaging the PEX tubing during removal.

4. Additional Tools for PEX Installation

• PEX Expansion Tool – Required for expansion fittings (e.g., Uponor/Wirsbo ProPEX).
• Clamp Tool – Used for stainless steel clamp connections (SSC method).
• Go/No-Go Gauge – Ensures that a crimp ring is properly sealed.
• PEX-Bending Support – Helps maintain bends in PEX tubing without kinking.

Cost & Availability

Prices for these tools can vary widely depending on the brand. Buying all the tools together in a kit can reduce the price.

Lower prices are also available online using Ebay, Google, or Yahoo to search for quality vendors with discounted prices (including warranties).

PEX Tool Compatibility

Each PEX connection method requires specific tools for proper installation. Understanding which tools work with different fittings is essential for compatibility and long-term reliability.

		Compatible PEX Connections
PEX Tool Manufacturer	PEX Tool Name	Standard Crimp Ring	SSC (Stainless Steel Clamp)	Proprietary Connection Type
Mil3	Compact Crimpmaker	Yes	No
Rehau	Comboloc, Versaloc, RAUPEX	No	No	Everloc
Ridgid	Viega ProPress Tool	No	No	ProPress
Ridgid	Viega Press Tool	No	No	Viega Press
Sioux Chief	PEX Crimp Tools	Yes	No
Sioux Chief	PEX Cinch Tools	No	Yes
Tradesmen Supply	PEXCaliber™ Crimp Tools	Yes	No
Tradesmen Supply	PEXCaliber™ Cinch Tools	No	Yes
Upanor / Wirsbo	ProPEX Expander Tool	No	No	ProPEX®
Viega	Viega ProPress® Tool	No	No	ProPress
Viega	Viega Press Tool	No	No	Viega Press
Wheeler Rex	PEX Ring Crimper	Yes	Yes
Zurn	PEX Crimp Tools	Yes	No
Zurn	PEX Cinch Tools	No	Yes

PEX Installation Tips & Best Practices

Whether you’re a DIYer or a professional, follow these best practices for a smooth installation:

• Proper Cutting – Always use a PEX tubing cutter to ensure clean, square cuts.
• Avoid Over-Crimping – Crimp rings should be snug, not crushed, to prevent leaks.
• Support the Tubing – Secure PEX with plastic or metal brackets to prevent sagging.
• Expansion Gaps – Allow space for expansion and contraction, especially in hot water lines.
• Temperature Considerations – Avoid prolonged exposure to high temperatures above 200°F.
• UV Protection – PEX should not be exposed to direct sunlight, as UV rays degrade the material.
• Secure Fittings Properly – Ensure crimp or expansion connections are done according to manufacturer guidelines.

Common PEX Installation Mistakes

Avoid these common mistakes when working with PEX:

• Over-crimping or under-crimping – Can cause leaks or weak connections.
• Incorrect fittings – Using non-PEX fittings can lead to compatibility issues.
• Bending PEX too sharply – Can cause kinks and reduce flow.
• Exposing PEX to UV light – Weakens the material over time.
• Not securing the pipe properly – Can cause movement, noise, and long-term stress on fittings.

PEX Certifications & Regulations

PEX plumbing must adhere to various industry regulations to ensure safety and durability:

• ASTM F876 & F877 – Standards for PEX tubing dimensions and performance.
• NSF/ANSI 61 & 14 – Certification for potable water safety.
• Local Building Codes – Some areas restrict PEX use, so always check local plumbing codes.
• Pressure & Temperature Ratings – Typically rated for 100 PSI at 180°F and 160 PSI at 73°F.

Maintenance & Longevity of PEX

PEX has a lifespan of 40-50 years, depending on water quality and environmental conditions.

• Does not require regular maintenance – Unlike copper, it won’t corrode or develop pinholes.
• Withstands pressure and temperature fluctuations – However, extreme conditions can degrade it over time.
• If repairs are needed, cut the damaged section and replace it with a coupling.

PEX for DIY vs. Professional Use

PEX is DIY-friendly, but some cases require a plumber:

Factor	DIY-Friendly	Call a Plumber
Running new water lines	✅	❌ (for complex layouts)
Repairing leaks	✅	❌ (for major leaks)
Connecting to existing plumbing	✅	❌ (if soldering is needed)
Municipal water connections	❌	✅
Large-scale home renovations	❌	✅

Final Thoughts

PEX piping is a cost-effective, flexible, and durable alternative to copper and PVC plumbing. Whether you’re a DIYer installing a small repair or a professional designing a high-pressure water system, understanding the different types of PEX, best practices, and regulations ensures a successful plumbing project.

If you enjoyed this article, please feel free to check out the appliances, home improvement, and bathroom categories on the website.

Happy plumbing!

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