What Is PEX Plumbing?

PEX has created quite a buzz in the plumbing industry and has left most people wondering what is PEX plumbing. PEX or Cross-linked Polyethylene is a revolutionary product that has only recently been introduced to the market. PEX is like a breath of fresh air in a market once dominated by galvanized pipes. If you are wondering about the nitty-gritty of PEX plumbing, we suggest you read this article till the last word. So, let’s get started!

History of PEX Pipes

The origin of PEX pipes dates back to 1968 when the German scientist Thomas Engle discovered it. He found that a much supple form of the already existing common plastic or polyethylene could be created through radiation. This plastic was first introduced to the US in the form of PEX pipes during the 1980s.

In the initial days, it was mostly used for radiant floor heating systems. Here, the PEX tubing was embedded in concrete slabs and had hot water passed through it. This would heat the concrete and radiate the warmth through the rest of the rooms. Although first popularized through this form, PEX applications still remain popular in the floor heating sector.

In Europe, however, PEX has been more popular for its utility in the water supply systems ever since the 1980s. But, due to the high chlorine content in most of the US water supply systems, a few early versions of PEX were corroded.

With modern innovations, scientists found out that adding antioxidants to PEX during its manufacture made it suitable for transporting drinking water. Regular testing has concluded that after this treatment, PEX meets its potable drinking water standards. As a result, PEX is now being widely used all over America to serve drinking water for over two decades.

Although PEX was already on the path to fame, leaks in the fittings and loose connections were some of the complaints received in its early days of being used in water systems. However, with the subsequent improvements, such complaints gradually died down, and the popularity of PEX increased significantly. As a result, PEX has become such an essential part of the plumbing industry that it is being used in 60% of residential water supplies.

Types of PEX Pipes and Their Uses

PEX is highly versatile in nature. It is available in various lengths, ranging from pieces of 10-foot length each to rolls of PEX reaching up to the length of 500 feet. While the former is used for small repairs, the latter is used for installing the entire water supply system of a home.

Its diameter can be anywhere between ⅜ to 1 inch to suit your various needs, and its color-coding system clearly helps you understand what each pipe is used for. PEX can be classified based on two systems- color and the type of labeling.

Classification Based on Color

Although this is not exactly a proper classification, it can still be considered one because it tells the user which pipe carried hot and cold water.

1. Red PEX- This pipe carries hot water.
2. Blue PEX- Pipes that are blue colored carry cold water.
3. White PEX- They can be used to carry either hot or cold water.
4. Gray PEX- Similar to white PEX pipes, they can also carry hot and cold water.

Classification Based on Manufacturing Procedure

PEX rolls are generally labeled as either A, B, or C type, based on the manufacturing process they undergo. The following are the main classifications of PEX-

1. PEX A- This type of PEX is manufactured using peroxide, and it is the most flexible out of all the PEX types. Widely used in all water-supply needs in most homes, they expand a lot when subjected to freezing water and hence are actively resistant to cracking in severely low temperatures.

Although more expensive than the B and C types, they are mostly worth their price. Depending on the brand and diameter, a PEX measuring 10 feet in length can range from $3.50 to $7.50. Flexibility is one of the only advantages that PEX A has over the other two.

2. PEX B- This type of PEX is manufactured using moisture-cure. It is not as flexible as PEX A, and its coil memory returns this type to its original coiled state. However, despite its coil memory, PEX B is the more popular choice when it comes to residential plumbing. This is because it expands significantly on freezing and is also quite less expensive than PEX A.

Depending on the brand and diameter of the tube, PEX B ranges in price between $2.50 to $5.50. Besides that, one of the premier qualities of this type is its greater resistance to chlorine. This is an added benefit when it comes to transporting highly chlorinated water.

3. PEX C- This type is the cheapest version of PEX available in the market, ranging between $1.75 to $3.50. PEX C is manufactured using an irradiation method, and as a result, it is the stiffest out of all the other versions. So, it becomes extremely difficult to mold it according to the needs.

In addition, its stiffness also makes PEX C more susceptible to developing cracks when water temperatures reach below the freezing point. All of these features make PEX C an ideal choice for only short repairs where bending the pipe to fit sharp corners of buildings is not necessary.

Available Sizes of PEX Pipes

The available sizes of PEX pipes can be distinguished according to their diameters and lengths.

The Most Common Diameters of PEX Pipes

Half Inch: Mainly used for making branching lines for supplies, it is the most common diameter that DIY plumbers use for their projects. Branch lines in plumbing supply water from the main pipe to bathroom and kitchen sinks, showers, flushes, and bathtubs.

Three-Quarter Inch: This type is specially designed for transporting water from a water heater, although it also supplies cold water to residential homes. However, the initial 18 inches of the PEX pipe cannot be used to supply water from a water heater.

The Most Common Lengths of PEX Pipes

PEX pipes are found in a large variety of lengths- both short and long. PEX pipes of 4 to 10 feet, which are ideal for DIY home plumbers, are widely available in the market. Apart from that, PEX pipes of lengths ranging from 100 to 500 feet are also available for use by professionals.

These lengthy pipes are instrumental in building the entire plumbing system of huge residential homes. They run through numerous supply points and branches to meet different supplies throughout the building.

Pros and Cons of PEX Pipes

Pros

1.  While copper and steel pipes require soldering to fit them together, PEX pipes do not need to undergo any such procedure. Instead, it is way easier to install them.
2. PEX is a compound that expands on reaching freezing temperatures. This makes them more resistant to cracking and damage at low temperatures that become a reality during winters. However, compared to this, copper and steel crack more easily.
3. PEX, being a plastic compound, is free from weathering and corrosion, something that copper and steel pipes are highly prone to. This might increase the risk of contamination.
4. The “water hammer” noise, largely associated with metal piping, can be conveniently removed by using PEX pipes for plumbing.
5. PEX pipes are available in various colors that express their type very clearly. Red and blue pipes are easy to distinguish between and minimize confusion, something that was a problem for copper and steel pipes.
6. With the appropriate fittings, PEX can be conveniently connected to the existing metal pipes. This is a result of their flexibility.

Cons

1. Although highly flexible, PEX should not be exposed to ultraviolet rays. Exposure to UV rays when PEX pipes are fitted outdoors leads to the rapid breakdown of the plastic compounds. This leads to the eventual hardening and cracking of the plumping system within only a few months.
2. PEX pipes are not environmentally friendly because they cannot be melted as easily as other plastic. This makes it more difficult to recycle. However, as PEX pipes become more popular, their need to be recycled will also rise and propel innovation in that direction.
3. Installing PEX pipes require special equipment and connectors, even though DIY enthusiasts can do it.

Application of PEX Pipes

Although introduced in the 1960s and accepted by most major codes for plumbing and building, there might be a few problems. According to the law of the area you are located in, there might be particular requirements or restrictions regarding PEX installations.

For correctly installing the PEX tubing, the standard procedure is to fix it with special metal crimps and barbed fittings. They are then secured using a special crimp tool. Once crimped into place, the ring is checked by the installer, ensuring its correct diameter. The PEX pipes, being DIY-friendly, can also be installed using push-in fittings. It can also be conveniently cut using a tubing cutter, especially for PEX pipes.

The following are a few applications of PEX pipes:

1. Portable distribution systems like pipelines are meant for supplying water.
2. In applications for radiant floor heating.
3. Applications where heat is transferred like floor cooling, protection from permafrost, and snow melting functions.
4. Applications for distributing hot water, like radiators.
5. Fire or sprinkler systems for residential areas.

Labeling Information on PEX Pipes

The following are a few of the most vital labeling to be found on PEX pipes:

1. The pressure or temperature rating according to each pipe
2. Pipes meant for potable drinking water must be marked with something appropriate.
3. Designations for ASTM fittings of the pipes to be approved and marked by the PEX manufacturers.
4. The trademark of the PEX pipe manufacturer
5. The designation code for the plumbing pipes.

How To Make PEX Connections

As discussed above, you will need the fittings and connections to exactly match the size of your PEX pipes. The following five methods are mainly followed to make connections watertight:

1. Copper Crimping Rings- With the help of a special PEX crimping tool, PEX pipes can be connected to copper crimping rings. To achieve this correctly, the copper ring is slipped over at one of the PEX pipe end to which a fitting is inserted next. After this crimping ring is pushed to the tube’s end and over the fitting, this PEX crimping tool is used to crimp the ring securely into place.
2. Expanding PEX- This method of connecting PEX pipes together includes a particular PEX expander tool. It stretches the diameter of the pipe, after which the end of the other fitting can be conveniently inserted. Once this process is conducted, the PEX tube shrinks back to its original diameter, creating a watertight connection between the pipes.
3. The SSC Method- The SSC method or the Stainless Steel Clamping method involves using a clamping tool to make the stainless steel rings around the PEX pipes watertight. Before inserting the fitting, the stainless steel ring is inserted on one end of the PEX pipes. Then, the clamping tool is used to squeeze the ring and tighten it so that the fitting is securely held in place.
4. Compression- In this method, a brass nut is slipped over one of the ends of a PEX pipe. It is followed by a plastic compression ring and a hollow brass tube, all of which are inserted into the same end. Finally, after placing it inside a threaded fitting, the brass nut is screwed onto it. With the tightening of the nut, the plastic ring gets compressed against the brass ring, forming a seal at one end of the PEX pipe.
5. Push-fit Method- This is one of the quickest ways to fir PEX pipes together. Here, push-fit connections need to be purchased. They grab the end of the PEX pipes when inserted. Although exclusive tools are not required for this connection, to remove the push-fit fittings from the end of the pipes, a particular removal ring is required for it.

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