What is PEX A Tubing?
PEX-A or crosslinked polyethylene-A pipes are becoming a fixture in the plumbing industry, and for good reason. In order to appreciate the appeal of these pipes, let's delve into its distinctive structure, benefits, and where they are most commonly used.
The manufacture of PEX-A pipes involves a process called the Engel method, which enables a high degree of cross-linking. Cross-linking is the process where polymer chains are connected, forming a three-dimensional network of linked molecules. This complex structure is the backbone of PEX-A's standout features, contributing to its flexibility and durability.
What is PEX-B Pipe?
PEX-B pipes, also known as Crosslinked Polyethylene Type B, are produced using the Silane or moisture cure method of crosslinking. This process involves introducing silane compounds to the polyethylene, followed by exposure to heat or a catalyst that induces crosslinking, thereby forming a three-dimensional molecular network.
pex b vs pex a
Compared to PEX-A, the crosslinking of PEX-B occurs after the pipe is extruded, providing a distinct structure that differentiates it from other PEX types.
How to choose?
The choice between PEX-A and PEX-B pipe really depends on the specific application and personal preference, and market usage habits. But let's evaluate both based on their characteristics:
Property | Other PEX-A | PEX-B | |
Manufacture Method | Peroxid / Engel | Silane | |
Cross-linking Degree | 85% | 65% | |
Flexibility | Better flexibility than PEX-B | Stiffer to work and bend | |
Strength | Meets ASTM | Meets ASTM | |
Homogeneity | Not very good | Good | |
Thermal Memory | Good | Decreases after heating to transparency | |
Kink Reparability | Excellent | Decreases after heating to transparency | |
Kinking resistance | Good | Fair | |
(More vulnerable to be Kinked) | |||
Barrier property | Meets DIN 4726 | Meets DIN 4726 | |
Thermostability | Better than ASTM requirements | Better than ASTM requirements | |
Memory effect of being coiled | Fair - Better than PEX-B | Poor | |
Minimum bending radius | Good - Better than PEX-B | Poor - The worst of all PEX types | |
Kinking resistance | Good - Better than PEX-B | Poor | |
Density | 0.938 - higher | 0.941 - highest | |
Cost | Expensive | Cheaper |
Flexibility:
PEX-A is more flexible than PEX-B, which means it’s less likely to kink and easier to install. It can be bent and configured more easily around tight corners, which allows for fewer fittings and less potential points of leakage.
Durability and Strength:
PEX-B is often considered more durable and able to withstand high pressure. It also provides a higher burst pressure.
Resistance to Chlorine:
Both PEX-A and PEX-B perform well when exposed to chlorine in the water at recommended levels.
Price:
In comparison, PEX-A is typically more expensive due to its manufacturing process, but you may save on fittings due to its flexibility.
Fittings and Joints:
Both PEX A and PEX B can use brass compression fittings, pex sliding fittings, brass press fittings and pex crimp fittings. Besides the fittings same as PEX-B piping, PEX-A allows for the use of expansion fittings which create a more secure, leak-resistant joint, an advantage especially in freezing conditions.
Repair:
PEX-A offers a 'shape memory' feature, meaning it can return to its original shape, allowing for the repair of kinks or reshaping the expanded fittings, which isn’t possible with PEX-B.
Conclusion
To summarize, if you need a pipe for tighter corners or for more complex layouts, the flexibility of PEX-A may make it the better choice. If you need durability at a lower cost, PEX-B may be the way to go. A professional plumber can help you determine which is best for your project based on the specific requirements and local building codes. If you have any other questions or inquiry for pex tubing for plumbing or underfloor heating system, welcome to contact VPEXCO.
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