Your Fundamental Guide to Plastic Piping: PEX, PE, and Multilayer Pipe

When it comes to piping, there is no perfect material. Traditional metal pipes have their own issues just as plastic materials have their own. They also have their own benefits which make them ideal for certain applications.

When choosing the material for your pipes, the best way to go is to understand them – how they are made, their advantages and disadvantages, and other essential information. Once you do, the next step is to understand your needs and the options you have.

To give you a head start, here are some important facts you should know about the different plastic piping materials.

The Basics of PEX

Cross-linked polyethylene, widely known as PEX, is a type of plastic that is currently the preferred material of many industries over traditional galvanized steel and copper for water supply in new construction and renovation projects.

Let’s find out why.

A. What Is PEX?

PEX plays an integral role in a water supply system. It is known to offer more advantages compared to metal pipes, like lead, copper and iron, and rigid plastic pipes, like ABS, PVC, and CPVC.

PEX pipes are made from cross-linked high-density polyethylene or HDPE polymer. The crosslinking of HDPE makes bridges among each polyethylene molecule. The resulting material is more stable under extreme temperatures, chemical attacks, and better resistance to creep deformation. The HDPE polymer is melted and continually squeezed into the tube.

You may have noticed different colors of the pipes. However, these do not indicate the distinctions of each. The main purpose of these colors is to make it easy for installers to determine if the line is carrying hot water or cold.

• Red PEX pipes carry hot water.
• Blue PEX pipes carry cold water.
• White PEX pipes can either be used for cold or hot water.
• There are also gray PEX pipes that serve the same function as the white ones.

It comes in varying lengths. It can come in 10-ft. pieces for minor repairs and over 500-ft. long for residential water supply installation. PEX pipes range from ⅜ to an inch in diameter and their color coding make it easy to determine the function of a particular pipe.

B. Are There Different Types of PEX?

There are three types of PEX. They differ in what manufacturing process was used in making them. When buying PEX, you’ll notice labeling with either A, B, or C. Choose the pipe that will meet your requirements best.

• PEX-A

PEX-A is made using peroxide. Among the three types, it is the most flexible. This makes it ideal for residential water supply lines. It can expand to an immense degree when exposed to freezing water. This means it has the highest resistance to cracking in extreme temperatures.

It’s simple to work with. However, it’s the most expensive among the types. Except for its flexibility, PEX-A has no other important advantage over PEX-B.

• PEX-B

PEX-B is made through the use of a moisture-cure technique. It is a bit stiffer compared to type A. It has a specific “coil memory” that will make the pipes want to go back to their initial coiled state.

This memory, however, is not an issue when installing. This type is a common choice for home plumbing. It’s cheaper compared to type A and can also expand to withstand cracking in freezing water.

PEX-B is also highly resistant to chlorine, making it suitable for areas that have highly-chlorinated water.

• PEX-C

PEX-C is made through an irradiation procedure. It’s the most challenging to work with as it’s the stiffest among the three. Its stiffness makes this type most prone to kinking and cracking in freezing water.

These downsides make the type C most suitable for minor repairs and replacements wherein bending around the sharp corners is not needed. The good thing about this type is it’s the most affordable.

Here is an informative video that will give you more insights into the different types of PEX pipes

C. What Are the Applications?

Due to its strength, flexibility, and resistance to harsh temperatures, PEX is ideal for the following applications:

• Hot and cold water plumbing systems
• Hydronic cooling and heating systems
• Service lines
• Residential fire sprinkler systems
• Snow melting utilization
• Outdoor lawn conditioning
• Permafrost protection under chilled warehouses
• Systems in ice rinks

D. What Are the Advantages?

PEX is known to possess a lot of advantages. Here are some of them below.

A main advantage of PEX is its flexibility. This allows PEX pipes to connect their ends to PEX manifolds, otherwise known as the main water control system. Then, they will wind through floors and walls to the individual fixtures without any interruptions.

Widely known as the “home run plumbing,” this setup uses one length of PEX for both cold and hot water supply fixtures in residential buildings. This will greatly reduce the risks of leaks in numerous connection sites.

PEX pipes don’t corrode, which is common in both steel and copper pipes. Corroded pipes will potentially lead to leaks and water contamination.

Since it is resistant to corrosion, there is no longer a need for protective layers and finishes. This will help save expenses.

PEX installation doesn’t require soldering.

Through PEX, water flows quietly. This prevents the “water hammer noise,” which is connected with metal pipes.

PEX can expand. This means it has high resistance to freeze-cracking compared to steel and copper.

Through the proper fittings, PEX pipes can connect to an existing metal supply line.

The color-coding makes it easier to identify the cold and hot water supply lines.

E. What Are the Disadvantages?

While PEX is a top choice for water supply lines, it still comes with it a few disadvantages.

Even though DIY installation is possible, special tools and connectors are still needed.

PEX is not ideal for outdoor use. Ultraviolet (UV) rays can lead PEX pipes to break down right away. Exposed pipelines could harden and will potentially crack in just a few months.

As for now, PEX is not recyclable as it can’t melt like the other recyclable types of plastic. The good news is since the demand for PEX is continually increasing, the effort to find a way for recycling it will surely increase.

A Closer Look on PE

Polyethylene is a feasible material and one of the most competitive compared to traditional piping materials. Let’s find out more and see how sustainable this type of plastic is.

A. What Is PE?

Polyethylene, or PE, is a type of thermoplastic material and a product of ethylene polymerization. PE plastic pipes are made through an extrusion process in sizes that range from ½” to 63”.

PE comes in rolled coils of different lengths. It is also available in straight lengths that can reach up to 40 ft. It is made from a material that can both be reformed and melted.

B. What Are the Applications?

PE pipes are a cost-efficient solution for a wider range of pipe challenges in industrial, mechanical, agricultural, mining, and maritime applications. It’s already proven that these pipes are ideal for surface, above ground, buried, floating, sliplined, and subsurface marine operations.

PE pipes can transport the following medium:

• Potable water
• Slurries
• Wastewater
• Hazardous Wastes
• Compressed Gases
• Chemicals

For so many years, PE pipes are known to serve the mining, oil, gas and other industries. It’s popular to have the least repair frequency per kilometer of pipe each year as compared with other pipe materials utilized for urban gas applications.

C. What Are the Advantages?

PE also possesses several advantages making it a top choice of material for many customers.

• It is corrosion-resistant. Corrosion is an expensive issue most metal pipings encounter. It can happen both inside and outside the pipes and will affect hydraulic performance.
• Many areas will treat water to slow down pitting and rusting, which are hard to avoid with metal piping. Other prefer more expensive means like plastic coating, cathodic protection, and sleeving to help extend the lifespan of the pipes.
  Unlike traditional metal materials, PE doesn’t corrode, rust, or rot. It also has resistance to biological growth. This means the pipes will last longer and there is a significant cut on the costs.
• The joints are leak-free. Traditional piping is connected with spigot and bell or mechanical joints. All of these are associated with a particular leakage factor. Not only are areas losing water, but unnecessary costs are also increasing. PE pipes can be connected with heat fusion to create joints that are leak-free permanently.
• It is resistant to fatigue. PE pipes are both ductile and flexible. PE is designed to withstand fatigue, which is a bit common in water supply systems. In many occasions, this allows people to use a thinner wall of PE pipes compared to other plastic piping types.
• Environment-friendly. PE has minimal effect on the environment. It only requires less energy to make it compared to other plastic types. Compared to traditional metal pipes, it is both lightweight and cost-efficient.
• It is adaptable. PE pipes can be connected with mechanical and stab fittings. There are a variety of fittings available, which are specific to the size and application of the pipes. However, PE pipes can easily transition to and from non-PE pipes through the use of stab fittings, flanged and mechanical connections, and mechanical joint adapters.
• It is fully recyclable. PE pipes can last more than a hundred years and even after their service life, they can be recycled. They may be collected and reformed into other PE products. This feature is both cost-efficient and eco-friendly.
• It’s suitable for trenchless installations. Due to its flexibility and durability, PE is a top option for trenchless installations. This type of installation method is good for the environment to protect natural habitats, plant life, and root systems underground from getting disturbed.

D. What Are the Advantages?

Even how great PE is, it still comes with some disadvantages.

• They are not fire-resistant. Although PE pipes can withstand high temperatures of water, they are not resistant to flame. They can melt easily at over a hundred degrees of temperature.
• Varying sizes are limited. PE pipes are only available in a few sizes between ½ and 2 inches.
• They are not suitable for outdoor use. Like most types of plastic, PE is not ideal to work for extended periods of time outdoors.

Exploring More About the Multilayer Pipe

A. What Is a Multilayer Pipe?

A multilayer pipe also termed as PEX-AL-PEX/Pex-Al-PE/Pe-Al-PE(it depend on the material), is a pipe made up of an aluminum layer that is “sandwiched” between two layers of cross-linked polyethylene or PEX. The metal layer will function as an oxygen barrier, prohibiting the diffusion of oxygen through the polymer pattern. This stops it from dissolving into the water in the pipe and cause corrosion to the metal elements of the system.

The aluminum layer is slender, usually one to two mm. It offers some sternness to the pipe. This causes the pipe to retain its shape when bent. It also offers more structural sternness making the pipe ideal for higher safe-operating types of pressure and temperature.

Multilayer pipes come in NPS or nominal pipe sizes that range from ⅜ to 2 ¼. They are also labeled as DN or diameter nominal sizes that range from 12 to 75. These pipes have pressure ratings of 200 Psi at 73º Fahrenheit or 1380 kPa at 23º Celsius and 125 Psi at 180º Fahrenheit or 860 kPa at 82º Celsius. Multilayer pipes are usually sold in straight lengths and coils.

B. What Are the Applications?

Multilayer pipe was introduced first in North America back in the 19000s. Today, it is used in several applications including plumbing, ice, and snow melting systems, and hydronic cooling and heating among others.

• Refrigerated water piping
• Hot and cold water plumbing systems, both commercial and residential
• Outdoor ice and snow melting
• Radiant cooling and heating systems including ceilings, walls, and floors
• Pitch heating and turf conditioning
• Hydronic piping systems including fan coils and radiators

C. What Are the Advantages?

Multilayer pipes is also a growing favorite of many due to the following benefits:

• Lightweight and compact.
• Easy and fast to transport.
• Highly reliable and safe for potable water.
• Durable enough to withstand demanding site installations.
• Highly resistant to deposits, corrosion, and tuberculation.
• Flexible but stiff enough to retain its form.
• No flame is required to join it. There are also many options for connecting and fitting available.
• There is less longitudinal contraction/ expansion compared to the standard PEX and PE.
• The aluminum layer will prevent oxygen from infiltrating the pipes.

D. What Are the Advantages?

Just like the other materials, multilayer pipes also has some drawbacks.

• It is highly sensitive to UV light. This means that this material is also not ideal for outdoor use. Not only sunlight, but multilayer pipes should not be exposed to UV lights inside homes and buildings as well.
• It can be damaged easily by pests and chemicals. Since it is made from plastic, this material is more prone to damage made by pests and chemicals compared to metal pipings like copper.
• It is not suitable for high-heat areas. This means you cannot connect multilayer pipes to a water heater directly. However, this can be made possible through a connecting material.

At The End

With all the material options you have, it could get overwhelming. The good news is, you now have a pretty good picture of the different types of plastic piping. All you have to do now is to weigh them all in and figure out the best one that will meet your requirements best. Also, you can always consult professionals so you can make an informed decision. You can start by checking out Tubomart today to get the best plastic pipe materials for your project!

Good luck!