PEX-AL-PEX: A Basic Ultimate Guide for Beginner

In this blog post, you’ll read:PEX-AL-PEX pipes revolutionize plumbing with their composite structure of PEX layers bonded by aluminum, offering flexibility, durability, and high resistance to temperature and pressure. Ideal for potable water, underfloor heating, and solar thermal systems, they combine strength and ease of installation. This guide covers their composition, uses, advantages, and how to find reliable manufacturers.
Table of Contents

Polyethylene Aluminum Composite Pipe is known as PEX-AL-PEX. With diversified strength and durability, it brings a revolutionizing change in plumbing technology. Thus, this guide is tailored to help you learn about PEX-AL-PEX pipes. It covers everything from composition to installation methods. Additionally, it explores their advantages in plumbing systems for beginners.

1. Introduction to PEX-AL-PEX Pipes

This is a composite pipe with layers of PEX bonded by thin layers of aluminum. It is a combination of materials to give flexibility, corrosion resistance, and high pressure. It provides high-temperature resistance, structural stability, and oxygen impermeability. This allows it to be used in all water applications, including cold and hot water and radiant heating systems.

2. Uses of PEX-AL-PEX Pipes

2.1. Water Drinking Systems:

PEX-AL-PEX pipes find maximum applications in the potable water supply. This may be attributed to their ability to withstand corrosion and scaling. The middle layer of aluminum provides an oxygen barrier. Thus maintaining the quality of the transmitted water. These pipes work well with both cold and hot water in domestic and industrial uses.

2.2. Underfloor Heating Systems:

underfloor heating systems
underfloor heating systems

Due to flexibility and resistance, PEX-AL-PEX pipes are applied in underfloor heating systems. The incorporation of the aluminum layer enhances heat conduction. This increase in radiant heating efficiency meets high demand. It’s ideal for new constructions and retrofitting processes. These applications focus on even heat distribution and energy efficiency.

2.3. Hydronic Heating Systems:

hydronic heating systems
hydronic heating systems

PEX-AL-PEX pipes use water for the conveyance of heat in hydronic heating systems. They maintain great strength and baptize well to thermal expansions and shocks. They connect boilers, heat pumps, and radiators without a hitch. It allows effective heat transfer while the systems remain intact over time.

2.4. Solar Thermal Systems:

More often than not, PEX-AL-PEX pipes are used in solar thermal systems. They show very high temperature and UV resistance. In such systems, the aluminum layer acts as an oxygen barrier. This preserves the efficiency and life expectancy of solar heating components.

2.5. Renovation and Retrofitting:

PEX-AL-PEX pipes are flexible and installable in tight spaces. They are preferred for renovation works, which involve retrofitting existing plumbing systems. In this case, their ability to bend and adapt to existing structures reduces labor costs. Also, it lessens disruption during their installation.

3. Types of PEX-Al-PEX

3.1. PEX-Al-PEX A:

Using the “Engel” technique, this material is cross-linked. Before forming the polyethylene material, we incorporate peroxides.

The most versatile of the three, this form of cross-linked polyethylene can satisfy the infrastructure needs of your home’s water supply. The most cracking-resistant material in frigid conditions is the one that expands the most when subjected to frozen water. This option is more expensive than options B or C but is also simpler to manage.

  • PEX-Al-PEX B:

This pex-pipe is a material that undergoes cross-linking through the silane process, also called steam or moisture.

  • PEX-Al-PEX C:

Cross-linking this substance includes subjecting it to gamma or electron beam radiation. Out of the three cross-linking methods, the technique is least frequently used.

4. Pex-al-Pex: Dimensional Data and Specifications

PEX-AL-PEX Size (Nominal) Minimum wall thickness Outside Diameter
Inside Diameter
Weight lbs/100ft Volume gal/100ft
3/8″ 0.063″ 0.472″ 0.346″ 6.37 0.49
1/2″ 0.065″ 0.630″ 0.500″ 6.98 1.02
5/8″ 0.075″ 0.787″ 0.637″ 10.02 1.66
3/4″ 0.089″ 0.984″ 0.806″ 15.12 2.65
1″ 0.114″ 1.260″ 1.032″ 23.21 4.35

5. Material of Pex-Al-Pex

PEX-AL-PEX pipes are made of an aluminum strip in the middle of two layers of PEX. The welded metal functions as an oxygen barrier to prevent the corrosion of metallic components within the encircling heating system. The tube can be shaped due to the rigidity of the thin aluminum layer.

6. Composition of PEX-AL-PEX Pipes

PEX-AL-PEX pipes consist of three layers:

• Inner and Outer Layers of PEX:

These layers give flexibility and chemical resistance to the pipe. It allows it to work with a wide range of water qualities and environments.

• Aluminum Core:

The aluminum layer acts as an oxygen diffusion barrier. At the same time, it provides the necessary strength and stability to the pipe. It enhances thermal conductivity and thus makes PEX-AL-PEX pipes suitable for heating applications.

7. Advantages of PEX-AL-PEX Pipes


  • There are many options for joining the pipes, and no flame is used in the process
  • They are light-weight and easy to transport, hence reducing transportation costs
  • The aluminum layer in the pipe prevents oxygen from entering the pipe
  • They are flexible and also stiff at the same time; hence can maintain their shape
  • They are safe for use and can be used for a long period
  • They are strong and very durable, thus reducing long-term costs
  • Resistance to corrosion and deposits

8. Installation Methods

installation methods
installation methods

8.1. Compression Fittings:

Normally, compression fittings are used for PEX-AL-PEX pipes. It will attach the pipe to the fittings with the use of a compression nut and ring. This is quite easy and needs very few tools; hence, it can be done by any DIY person or professional. Compression fittings seals and do not need glue, heat, or soldering. Thus, change at installation time is easier.

compression fittings
compression fittings

8.2. Expansion Fittings:

PEX-AL-PEX pipes can also be installed using expansion fittings, yet another method that is used. This involves the expansion of the pipe’s end with some special tool whereby the fitting is inserted. The compression created when the pipe contracts makes it very tight and sealed to the fitting, making it secure. These fittings are preferred in areas where there is much worrying over leaks.

expansion fittings
expansion fittings

8.3. Press Fittings:

The press fittings technique is an incorporated hydraulic press tool. It crimps together the pipe and the fitting. Thus, it provides a fast installation with finality to the joint to avoid leakage. Press fittings improve the PEX-AL-PEX installation with the versatile solution. It offers residential, commercial, and plumbing applications, among others.

9. PEX-AL-PEX Vs PEX: What are the Main Differences

9.1. Structural Differences:

PEX-AL-PEX is triple-layered, with a middle aluminum layer sandwiched between the inner and outer PEX layers. Cross-linked polyethylene is used to bind this construction. So, it provides enhanced strength, durability, and resistance to temperature and pressure variations.

PEX, on the other hand, is plain one-layer cross-linked polyethylene tubing. It thus offers flexibility but low heat and pressure resistance.

9.2. Application Differences:

PEX-AL-PEX finds application in high strength, high resilience conditions, like hydronic heating systems and radiant floor heating. It is also used in applications requiring a barrier to oxygen permeation, like heating systems. Standard PEX finds its niche in applications requiring flexibility and ease of installation. It is used in potable water distribution and low-pressure plumbing applications.

9.3. Weight Differences:

A layer of aluminum makes PEX-AL-PEX piping heavier than regular PEX piping. This increased weight will affect their handling and installation at longer lengths or overhead installations.

9.4. Coil Memory:

Generally, there is less coil memory in PEX-AL-PEX than in standard PEX. The aluminum core will help the pipe hold its shape and round against being too tightly coiled, which firms up the pipe and makes it much easier to handle during installation without kinking. Standard PEX, being more pliable and elastic, may have more coil memory, and installation may be done less quickly in tight spaces.

9.5. Differences in Pressure Ratings:

PEX has ratings for use up to 200°F, or 93°C, in temperature and 80-100 psi of pressure, depending on the diameter and manufacturer. But, it is reinforced by the aluminum layer so that PEX-AL-PEX can bear higher temperatures—up to 200°F or 95°C—and pressures up to 160 psi or even more.

9.6. Different Connection Systems:

This is because of the structural composition of both PEX-AL-PEX and standard PEX connection systems. PEX-AL-PEX requires specific tools and fittings for the aluminum layer. These include compression or crimp fittings designed for this type of pipework. Standard PEX uses compression, crimp, push-fit, or expansion fittings tailored for its plastic-only composition.

10. Barrier PEX, Non-Barrier PEX, or PEX-AL-PEX: Which to Use?

The selection of Barrier PEX, Non-barrier PEX, or Pex-Al-Pex will be determined by the undertaking and the other components with which it will be used. All are polyethylene cross-linked (PEX), although more features have enhanced some.

10.1. Barrier PEX

The oxygen barrier is an additional conduit layer that ensures no oxygen will enter the heating system. The potential issue is that the components may corrode once oxygen is introduced.

Instead of bronze and brass, the oxygen barrier permits the incorporation of cast iron elements into the system. Thus, the components, including pumps and flanges, are less costly and can operate for an extended period.

The barrier pex is the preferred option for radiant heat systems. This tubing method is cost-effective when purchasing components and will prevent oxidation and corrosion.

10.2. Non-Barrier PEX

Non-barrier PEX is merely PEX that lacks an oxygen barrier. This type is employed in applications that require potable water. Barrier PEX is approved for thermal applications but not plumbing and potable water.

It is imperative to be cautious when employing non-barrier pex to ensure that each system component lacks iron. In radiant heat applications, this form of conduit is uncommon.

10.3. Pex-Al-Pex

This particular type of conduit is observed in inner heating systems, outdoor heating systems, and high-temperature systems, including fan coils and baseboards.

The widespread use of pex-al-pex pipelines originated in radiant heating systems. These pipelines are optimal for this application because they maintain their original shape. Additionally, they are employed in many applications, such as:

  • Distribution of hot and cold water infrastructure in both residential and commercial settings
  • Radiant heating and cooling application areas include ceilings, flooring, and walls.
  • Melting of snow and ice in outdoor environments
  • Turf conditioning and pitch heating
  • The piping of chilled water
  • Piping and distribution of hydronic fluid
press brass fittings
press brass fittings

How to Find a Reliable Pex-Al-Pex Manufacturer?

Several things should be taken seriously when finding a reliable PEX-AL-PEX manufacturer to ensure that the high quality of products matches the reliability of service. Several key points have been described in detail below:

1. Pex-al-Pex Quality and Certification

First and foremost, a supplier must be able to provide PEX-AL-PEX pipes that align with international quality and safety standards. It is good if products have ISO 9001 and ISO 14001 certifications. These denote that products are manufactured following tight processes and standards. Additionally, products should bear relevant industry standards, such as ASTM, DIN, or EN.

2. Manufacturing Experience and Reputation

Check the level of experience the manufacturer can commit to manufacturing PEX-AL-PEX pipes. The longer a company has been in business, the more likely it is to be a reliable and consistent producer of fine products. Therefore, consider manufacturers with a long history and reviews from other customers or industry-recognized professionals.

3. Technical Support and Service

Also, good technical support is essential, especially when issues arise regarding the installation or performance of the pipes. Go for a manufacturer that has well-developed customer service and technical support. This could be in terms of customer service representatives who are always available, technical documentation, and even on-site support if necessary.

4. Production Capacity and Scalability

Consider the production capacity and scalability of your future manufacturer. It is needed in large or continuous projects requiring continuous supply for the PEX/AL/PEX pipes. Ensure they can meet your demand without compromising on quality or delivery time.

5. Customization and Flexibility

Depending on your needs, the product’s customization flexibility might be valuable. Some projects require tailored dimensions, colors, or other specifications. Be sure to ask the manufacturer about the possibility of providing such services and the cost and lead times.

6. Testing and Quality Control

query the testing and quality control procedures involved by the manufacturer. Quite to the contrary, reputable manufacturers conduct rigorous testing in dimensional relation to the production process to ensure that their pipes meet performance standards and durability requirements. This may include pressure testing, dimensional checks, and material composition analysis.

7. Cost and Pricing Transparency

Value for money While cost is always a factor, it need not be the overriding consideration. The low prices may indicate that he has compromised on quality or service. Ensure that the price is transparent and demonstrates the product’s quality and features. Besides that, consider the total cost of ownership, installation, maintenance, and possible repairs.

8. Stability and Reliability Of The Supplier

Assess the manufacturer for stability and reliability as a supplier. Check whether they are financially stable and discuss their supply chain management practices with them. A manufacturer with a stable supply chain is less likely to be hit by disruptions that may impact your project timelines.

9. References and Industry Connections

Get references from other clients or associates who have dealt with the manufacturer. Their experiences will give you a first-hand feel of where the manufacturer stands regarding the reliability, service, and performance of their products.

10. Environmental Considerations

Next, consider the manufacturer’s commitment to environmental sustainability. Approach those companies that work within the environmental regulations and practice responsible sourcing and production methods.


PEX-AL-PEX pipes combine PEX flexibility and aluminum strength. These pipes find broad applications in plumbing and heating. They are easy to install in various settings. Their long-term reliability suits residential, commercial, and industrial projects. Beginners grasp their composition and manufacturing easily. They benefit from versatile installation methods. Maintenance considerations ensure prolonged performance in buildings. Feel free to contact us if you have any queries.

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