Choosing PEX Pipe & Fittings for Plumbing

A Pex pipe is a type of plastic plumbing pipe made from cross-linked high-density polyethylene (Pex). As a result, these flexible, durable and easy-to-install pipes have become increasingly popular over traditional copper and PVC pipes for plumbing systems among homeowners and builders. Pex pipes can withstand high temperatures and pressures, making them suitable for a variety of plumbing purposes including hot and cold water distribution, radiant floor heating, and snow-melting systems.

Whether you are planning to install new plumbing in your home or upgrade your existing system, Pex pipes offer a reliable and cost-effective solution that can save you time and money in the long run. In this article, we will explore the types of Pex pipe and Pex fittings as well as provide you with all the information you need to know about this amazing piping material. Let’s get busy!

Types of Pex Pipe

When it comes to categorizing Pex pipe, we can divide them according to their type, color, and size. For anyone who plans to buy Pex pipe, listed below are the most visible features.

Type

Generally, there are three types of Pex pipe:

1. Pex-A: First, Pex-A pipe is the most flexible and durable of the three types. Manufacturers use a high-pressure peroxide method, which gives it a consistent cross-linked structure. In addition, Pex-A pipe can withstand high temperatures and pressures and is resistant to chemical corrosion.  It also has memory properties, meaning it can return to its original shape after being bent. However, Pex-A is typically the most expensive type.

2. Pex-B: Pex-B pipe is made using a silane method that produces a less consistent, slightly less flexible molecular structure. It is still quite durable and suitable for most plumbing jobs. On the other hand, it costs less than Pex-A, and plumbers often use it in homes and businesses.

Figure 1

3. Pex-C: Finally, makers produce Pex-C with an electron beam, which gives it a more irregular structure. As a result, it is the least flexible type and has a slightly higher risk of failure. For this reason, larger commercial projects typically use Pex-C.

For example, the table below compares the three types.

Table 1

Besides these three, there are other variations, such as oxygen barrier Pex, which keeps oxygen out of the water. This type can be used in radiant heating systems. Above all, consult a plumbing professional to determine which Pex pipe type is appropriate for your specific job.

Color

Pex pipes are commonly available in three colors: red, blue, and white. In general, the color indicates its intended use and helps in the installation process.  For example, red Pex usually carries hot water, while blue carries cold. Meanwhile, white Pex works for either.

Still, it is always best to check the manufacturer’s instructions to ensure that you are using the appropriate type of Pex pipe for your specific installation.

Figure 2

Size

Pex pipe is available in ¼ to 1 inch diameters. The most popular sizes are ¾ and ½ inch but you can also find them in 1 inch as well as smaller sizes such as ⅜ and ¼ inch.  Typically, small-scale projects use the smaller sizes.

Pex Fittings

Pex fittings are used to connect different Pex pipes together and also to connect Pex to other types of pipes such as copper, providing a secure, leak-free connection. Moreover, they come in many sizes, usually in brass, plastic or stainless steel. Of course, the type of fitting depends on the specific use and Pex pipe type. There are various types of Pex fittings available, including:

1. Coupling: Joins two Pex pipes in a straight line.

Fig. 3

2. Elbow: Changes the direction of the pipe. It is available in different angles such as 45 degrees or 90 degrees.

Figure 4

3. Tee: Connects three Pex pipes in a T shape.

Fig. 5

4. Reducer: Connects pipes of different sizes. One end is larger than the other, allowing for a transition between two different pipe sizes.

Figure 6

5. Valve: Controls the flow of water. There are different types of valves such as ball valves, gate valves, and angle valves.

Fig. 7: Pex Female Brass valve

6. Adapter: Connects Pex to other pipes, such as copper or PVC.

Figure 8

7. Cap: Seals the end of a Pex pipe.

Fig. 9

8. Cross: Connects four Pex pipes.

Figure 10

How to Connect Pex Fittings

Next, you can connect these fittings in several ways.  The method used depends on several factors including the Pex type used.  The following explains the most common connection methods used for Pex fittings.

1. Crimping

First, crimping is one of the most popular and cost-effective methods for connecting Pex fittings. A crimp ring made of copper or stainless steel slides over the Pex tubing, Then a crimping tool compresses the ring around the tubing and fitting for a leak-proof seal. This method can be used with Pex-A, Pex-B, and Pex-C.

Fig. 11

Figure 12

2. Clamping

Clamping is another popular and affordable method for securing Pex fittings. A stainless steel clamp ring is placed over the Pex tubing and the fitting, Then a clamp tool tightens the ring around the tubing and fitting. One of the benefits of this method is that you can use the clamp tool for every ring and fitting size. This method can be used with Pex-A, Pex-B, and Pex-C.

Fig. 13

Figure 14

3. Compression

Compression fittings use a threaded nut, a compression ring (ferrule), and a fitting body to create a leak-proof connection. Next, you insert the tubing and tighten the nut, which compresses the ring into a seal. Also, this method needs no special tool. This method can be used with Pex-A, Pex-B, and Pex-C.

Fig. 15

4. Push-fit

Similarly, push-fit fittings install quickly without tools. You simply push the tubing into the fitting, and a locking mechanism that holds the tubing securely in place. Sharkbite fittings are a type of push-fit fitting that uses a unique design to grip the Pex tubing securely. The fitting has a stainless steel grip ring that holds the tubing in place and a specially designed O-ring that creates a watertight seal.

If your work simply requires a few connections or you are doing a small repair, the SharkBite will likely be the fitting system of choice because it is easy to use and requires no equipment; nevertheless, the fittings are more expensive per piece than the other systems. This method can be used with Pex-A, Pex-B, and Pex-C.

Figure 16

5. Expansion

For the expansion method, you need an expansion fitting, expansion ring, and expansion tool to stretch the Pex tubing, allowing the fitting to be inserted into the Pex tubing. The tubing then shrinks back to its original size, creating a tight seal around the fitting. This method is commonly used in commercial plumbing jobs and can be used only with Pex-A.

Fig. 17

Figure 18

6. Press

Press fittings use a press tool to create a permanent connection between the Pex tubing and fitting. The fitting has a stainless steel sleeve that is inserted over the Pex tubing, and a press tool then compresses the sleeve for a secure, leak-proof seal. It is worth noting that you should choose the press tool corresponding with the size of your Pex pipe and fitting. This method can be used with Pex-A, Pex-B, and Pex-C.

Fig. 19

Figure 20

Which Pex Pipe is Best for Your House?

Choosing the Pex pipe type for your house will depend on various factors, such as the specific needs of your plumbing system, budget, and personal preference. Here are a few things you should consider when choosing the Pex pipe type for your house:

1. Local building codes and regulations: Check your local building codes and make sure you are permitted to use Pex piping in your area. It is important to ensure that the pipe you choose complies with local building codes and regulations. According to the Plumbing Code 2018 of Philadelphia (adopted with amendment International Plumbing Code 2018 (IPC 2018) you are allowed to use Pex in Philadelphia.
2. Purpose: Different Pex pipe types are better suited for different purposes. For example, Pex-A may be more suitable for hot water lines, while Pex-B is a common choice for general plumbing lines.
3. Cost: Pex-A is typically the most expensive Pex pipe type, while Pex-B and Pex-C are more affordable options. Consider your budget and weigh the cost against the benefits of each type.
4. Warranty: Different Pex pipe manufacturers may offer different warranties for their products. Consider the warranty offered for each Pex pipe type and factor that into your decision.
5. Professional Consultation: A professional plumber can help assess your plumbing needs and recommend the best Pex pipe type for your house. They can also ensure that the installation complies with local building codes.

In general, Pex-A and Pex-B are commonly used in residential plumbing systems due to their flexibility, durability, and ease of installation. Pex-C is less flexible but has excellent chlorine resistance, making it suitable for areas with high levels of chlorine in the water.

In Philadelphia homes, Pex-B is the most common type because it is affordable and reliable.

Which Connection Method Should You Use?

Choosing the correct connection method for your Pex pipes is important.  Although it is not a tough decision, you should compare the pros and cons of each connection method in order to decide which one best suits your needs. The Table below compares the different connection methods from various aspects to help you choose the right one.

Table 2

Conclusion

We hope you found this article informative and helpful in understanding the features of Pex pipes for plumbing systems. Since Pex pipe is becoming widely used, it is essential to learn about the different types, the fittings, and the connection systems available. By choosing the appropriate Pex pipe, fitting, and connection system for your installation, and following the manufacturer’s instructions as well as the local building codes, you will have a safe and reliable plumbing system. However, always consult a licensed plumber or contractor.

If you are in need of professional assistance with any Philadelphia area home renovation, feel free to contact Matrix Company Solutions Corp. for a free consultation. We will be more than happy to help!