Whether you’re building or remodeling your home, choosing the most suitable piping material is critically important in order to have a functional plumbing system without encountering any problems for many years to come. Although there are many piping materials available on the market today, PEX is being increasingly used in residential and commercial plumbing applications.
Reasons for Using PEX Piping
PEX, which stands for cross-linked polyethylene, is a plastic material that offers some notable advantages over other plumbing options, including copper, galvanized steel, PVC, and CPVC. In order to understand the reasons why more and more professionals and homeowners choose PEX over other piping materials, let’s take a closer look at its characteristics.
Flexibility of PEX Pipes
PEX is flexible enough to be bent 90 degrees without requiring any fittings. Conversely, rigid piping materials, like copper, galvanized steel, PVC, and CPVC, cannot be bent around structural elements. Besides extending the duration and increasing the overall cost of your project, cutting pipes and installing fittings increase the chances of leaks behind your walls. The risk of these occurring can be reduced with PEX. To minimize the risk of water leaks even more, plumbers can use PEX plumbing manifolds and separate, uninterrupted PEX lines to connect the main water supply line to each fixture or group of fixtures. Using a manifold and continuous PEX piping, for instance, separate water lines can be run to your kitchen, laundry room, and each of your bathrooms.
In addition to easing the installation process, PEX is compatible with many piping materials, including copper, galvanized steel, PVC, and CPVC. This allows you to switch from other materials to PEX and vice versa, according to your project specifications.
Because in a plumbing system pipes are also used to transport hot water, it’s important to make sure that the piping material you choose can withstand high temperatures. To begin with, ASTM doesn’t approve PVC pipes for applications that involve temperatures above 140°F. For hot water applications above that value, professionals recommend using copper, galvanized steel, CPVC, or PEX piping, which can easily withstand water temperatures up to 200°F.
In addition, metals are good conductors of heat. For example, uninsulated copper and galvanized steel pipes can lose between 22 and 34 BTUs per linear foot an hour. Therefore, metal water pipes that aren’t properly insulated can lose a lot of heat, increasing your energy bills. Although PEX can lose some heat to the surroundings as well, it has a lower coefficient of thermal conductivity than metals. However, the heat transfer from the hot water flowing through PEX pipes will depend not only on the thermal resistance of the material but also on the pipe wall thickness and insulation chosen.
Cost of PEX Pipes
PEX is significantly less expensive than copper and galvanized steel pipes, and about the same price as that of PVC and CPVC pipes. However, “PEX piping” is a generic term, which includes three pipe categories with different characteristics and price ranges.
- PEX-A piping, which is manufactured using the “hot” cross-linking method. This method involves cross-linking the polyethylene molecules at temperatures above the melting point of the polymers used. PEX-A piping is more flexible than PEX-B and PEX-C piping, expanding or contracting to a greater degree when subjected to hot or cold water. This type of piping also has the highest resistance to cracking when temperatures drop below freezing. Considering its unique characteristics, it’s easy to understand why PEX-A is more expensive than PEX-B and PEX-C piping.
- PEX-B piping, which is produced by placing the pipe in a hot-water bath, after using a catalyst during the extrusion process. Because the degree of cross-linked molecules ranges between 65% and 70%, PEX-B is stiffer than PEX-A. As a result, PEX-B doesn’t expand as much as PEX-A.
- PEX-C piping, which is manufactured with the help of an electron radiation beam, which breaks the existing bonds between molecules and creates new cross-linked bonds. Having the smallest degree of cross-linking, this is the stiffest piping option, susceptible to kinking and cracking under freezing conditions.
Durability of PEX Pipes
Compared to copper and galvanized steel pipes, which tend to corrode, rust, and accumulate mineral deposits due to exposure to water for prolonged periods of time, PEX provides resistance to rust, corrosion, scale buildup, and other damage that water may cause. As a result, PEX piping prevents problems like discolored water, metallic taste, noisy pipes, low water pressure, and burst pipes.
PEX Piping Limitations
Similar to PVC and CPVC, PEX breaks down under UV radiation. Additionally, PEX piping is susceptible to damage by extreme heat, flame, high concentrations of chlorine, and contaminants. For example, certain oil- or mineral-based products can alter the chemical composition of PEX, damaging both pipes and fittings.
If you’re unsure about choosing PEX for your piping or repiping project, our experienced professionals can help you assess whether this material is the right option for the unique requirements of your plumbing system. If you have any questions about PEX piping, contact us today!