Walk down any plumbing supply aisle in the country, and you’ll find the colorful plastic pipes made of cross-linked polyhelene (PEX) are gaining popularity. PEX is easier to work with than copper, less expensive, and more resistant to scaling and corrosion. And unlike metal pipes, PEX expands as it freezes and thaws, which reduces the risk of cracked or burst pipes and water hammer.

While PEX pipes are safer and more durable than copper, there are some important things to consider before installing it in your home. Make sure you read the manufacturer’s label and check for proper installation standards. You should also choose a reliable, well-known manufacturer, and ask to see the manufacturing process used for the pipe you are buying.

There are three main types of PEX, based on the method used to create the cross-linking: PEX-a, PEX-b, and PEX-c. However, these designations do not indicate a quality rating. All three types meet or exceed minimum ASTM requirements and are safe for plumbing and heating installations.

PEX-a is manufactured using the Engel method, and has the highest resistance to long-term oxidation. It is the stiffest of the three types, and has a coil memory, which makes it difficult to bend. It also has a lower resistance to kinking and is only repairable with a coupling.

PEX-b is produced using electron beam processing, which uses a “cold” cross-linking method below the crystal melting point. This produces a more uniform, but lower-degree of cross-linking than the Engel method. It has a lower bursting pressure and a higher tolerance to kinking than PEX-c, but it is still safe for residential use. pex tubing