How Do I Know If I Have PEX A or PEX B?
Cross-lined polyethylene (PEX tubing/pipe) has become one of the most common materials used in plumbing systems: it’s a cheaper and faster-to-install option than traditional copper and steel pipes. PEX is also exceptionally flexible and durable. Like most pipes, PEX piping is of different types, with PEX A and PEX B being the common variant.
Both of the above two variants are readily available in the market and often appear to have more similarities; thus, not everyone can easily distinguish between the two. This article looks into their similarities and how to identify each one of them.
What is PEX A?
PEX A tubing is produced (cross-linked) through the Engel method, which entails continuously melting high-density polyethylene (HDPE) and adding peroxide to improve bonding. Generally, this PEX form has a high cross-linking ratio, making its chemical bond quite strong. As a result, PEX A tubing tends to be more flexible, resistant to kinking, and easily accepts expansion-style fittings.
PEX A tubing is slightly more expensive and stronger than PEX B pipes. It also has a lower bursting pressure and is more likely to burst quicker in freezing temperatures than PEX B tubing.
What is PEX B?
PEX B tubing is produced through the Moisture Cure method, which entails extruding HDPE and using Silane as a catalyst to trigger cross-linking. The HDPE formed is then passed through steam (hot water). PEX B is the common type of PEX tubing sold out there, and it is a slightly stiffer material. Also, PEX B tubing has a better resistance to oxidation and higher bursting pressure.
However, PEX B tubing has a noticeable coil memory and is not kink-resistant. It also uses a reduced-size fitting, which could increase flow restriction.
Similarities between PEX A and PEX B Pipes
PEX pipes are very similar as they all come from cross-linked polyethylene. Usually, the letter following the name “PEX” signifies the manufacturing method used to cross-link the polyethylene. Also, PEX A and PEX B are the same size and meet Copper Size standards.
These forms meet other standards, such as NSF/ANSI/CAN 61 (standard for installation in drinking water distribution systems) and ASTM F876 (performance standard). Above all, they all have the same function.
How to Identify PEX A and PEX B Pipes
As you can tell, there are many similarities between PEX A and PEX B tubing, and differentiating between the two just by a mere look is hard. Some people may buy the idea of identifying PEX pipes using color, whereby PEX A pipes often feature a white color (or slightly translucent). In contrast, PEX B pipes often feature a red or blue color (more opaque). However, counting on the color of pipes is unreliable because different manufacturers use different colors on PEX pipes. There are other variations you can use to identify PEX A and PEX B clearly, and they include:
1. Look for markings or labeling on the pipe
Looking at the marking is one of the easiest ways to identify PEX pipes since most manufacturers label them for this purpose. Usually, there are markings/printing on the exterior of PEX tubing that clearly says “PEX A” or “PEX B,” indicating the type of PEX tubing you have. The same markings are often accompanied by details such as the manufacturer’s trade name, CSA & ASTM Standards, size, material designation code, pressure rating, and length.
2. Examine the flexibility
Flexibility is another straightforward way to identify PEX A and PEX B piping. As highlighted earlier, PEX A is more flexible than PEX B, and you can easily bend it without kinking or deforming. PEX B is stiffer and easily kinks if bent into a tight radius.
3. Perform a “shape memory” test
One thing that distinguishes the two PEX tubing variants is how they retain their original form. This property is called shape memory. If you bend or expand a PEX pipe and it easily returns to its original shape (and no kinks), there is a high probability that it is a PEX A pipe. On the other hand, if you expand or stretch a PEX pipe and it can hardly regain its original shape, there is a high probability that it is a PEX B tubing.
4. Identify the style of fitting
Another way to identify the type of PEX pipe you have is to look at the style of fittings used. PEX A pipes often use expansion and contraction-type fittings. It also means you are required to use an expansion tool such as the iCrimp IWS-F1960 or IWS-1960D-34 PEX Expansion Tool Kits.
Conversely, PEX B pipes often use insert-style fittings and crimp or clamp rings. Also, these types of fittings and rings will require different tools, i.e., a clamp or crimping tool. Such tools include the iCrimp IWS-1234P PEX Crimping Tool and the iCrimp KIT-1096D Clamp Tool Kit.
Read more: Is it Better to Clamp or Crimp PEX?
Identifying the type of PEX pipe installed on your plumbing system or that you intend to install is essential. As discussed above, PEX A tubing is more flexible, maintains a good memory shape, and uses expansion/contraction fittings. On the other hand, PEX B tubing is stiffer, easily kinks if bent in a high radius, and uses insert-style fittings.
It’s worth noting that when working with these two variants of PEX tubing, it’s crucial to have the right tools. For this reason, iCrimp provides high-quality, user-friendly, and affordable tools for PEX tubing of different sizes. They include PEX pipe cutters, expansion, clamp, and crimping tools.