Developed in Europe in 1968 and introduced to the United States in the mid-80s, PEX piping has become one of the most commonly used materials in residential plumbing systems over the past 15 years.
When you see PEX-A, PEX-B, and PEX-C, you may be wondering what the difference is between them and which one should you choose. Below, we analyze why there are three PEXs, what characteristics they share, and how they differ.
How PEX piping is similar
As we all know, PEX stands for cross-linked polyethylene. The latter letter simply indicates the type of manufacturing method used to cross-link the polyethylene, not the grade of PEX.
If you look at the International Plumbing Code, you'll only see references to PEX, not the different types. This is because, in general, all PEX pipes are very similar.
1. They must all meet the same performance criteria. There are certain requirements that apply to all PEX pipe used in commercial and residential plumbing applications. Others apply to the PEX used in a particular system or application. Some examples include:
ASTM F876, which is the performance standard for PEX pipe.
NSF/ANSI/CAN 61 when installed in water distribution systems.
Application-specific standards such as UL 1821 for PEX pipe for multi-purpose fire suppression systems.
2. They are identical in size. PEX dimensions do not vary between PEX-A, -B, and –C, as defined in ASTM F876. They are all Copper Tube Size, or CTS.
3. They all have material designation codes. All PEX pipe is assigned one of these codes based on its chlorine resistance, UV resistance, and hydrostatic design basis (HDB) level, or pressure rating.
So what's the difference between the PEX types?
The truth is, not many. Again, the main difference is the manufacturing method, which is the method of assigning A, B, or C to the PEX.
1.PEX A is manufactured using peroxide or Engel method.
2. PEX B is formed using silane or moisture cure methods. This is the most common type of PEX piping.
3. PEX C is created using electron irradiation or cold crosslinking methods.
There may be slight differences in density, burst pressure levels, and bend radii between PEX pipe types, but they are negligible. However, no matter which PEX pipe you use, there are a few key differences to be aware of.
About IFAN PEX Pipe
There's no hard-and-fast rule for which PEX pipe — A, B or C — you should use. Given all the similarities and easily identifiable differences, your selection will be based more on your relationship and experience with a particular PEX tubing, your budget and the pipe’s availability in your area. Please contact IFAN if necessary.