Monday, June 13, 2011

Which Style Of Pex Tubing Should I Use?

PEX Tubing: Barrier vs Non-Barrier vs PEX-AL-PEX

Once you have decided to use PEX, you have another decision to make: what kind? Barrier, no barrier, aluminum, let's get them straight. Making the decision of whether to use Barrier PEX, Non-Barrier PEX, or PEX-AL-PEX is largely based on what job you are going to use it for and what other components you will be working with. All three types of tubing are PEX (Poly Ethylene X-Linked) but some have extra features built in.

Barrier PEX

The "barrier" referred to in PEX tubing is actually an oxygen barrier. This extra layer in your tubing will assure that no oxygen gets into your heating system. Oxygen in your system can be a problem that causes your system components to rust. The oxygen barrier and rust prevention allows you to use cast iron components in your system instead of all brass or bronze, which makes components like pumps and flanges substantially less expensive and keeps them running smoothly for longer. Antifreeze can also break down a system with no oxygen barrier. For radiant heat applications using closed systems, barrier tubing is by far the most popular choice. This style of tubing will save you money when buying parts and will prevent rust and corrosion.

Non-Barrier PEX

Non-barrier tubing is simply PEX tubing without the oxygen barrier. For potable water applications, you will generally use non-barrier PEX. Oxygen barrier PEX is made for heating applications and has thus not been approved for plumbing and drinking water. When using tubing without an oxygen barrier, you must be careful to assure that each and every component in your system is non-ferrous (meaning that it contains no iron). Non-barrier PEX Tubing is rarely seen in radiant heat systems, the few systems that do utilize non-barrier PEX are open systems. Non-barrier PEX for plumbing is available in red, white, and blue. Typically, red is used for hot water and blue is used for cold so that you can immediately see which line goes where when looking at a manifold.


PEX-AL-PEX is a three-layer PEX Tubing that also has an oxygen barrier. PEX-AL-PEX is a layer of PEX, a layer of aluminum, and another layer of PEX. The main benefit of PEX-AL-PEX is that it holds its shape. Where traditional PEX is flexible, there is nothing that keeps it in place unless you tie it down every few feet. With PEX-AL-PEX, once you bend it, it will hold that shape until you bend it again. PEX-AL-PEX also has less expansion than standard PEX with the layer of aluminum assuring that it keeps its shape. PEX-AL-PEX is frequently used in outdoor heating applications, warmboard systems and for high temperature systems like baseboard and fan coils.

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