Pex Pipe and Fittings

PEX Pipe and Fittings

PEX is a flexible plastic pipe that installs very quickly and easily.

Extruded polyethylene (PEX) pipe has taken the place of polybutylene (PB) pipe, which does not meet current codes because of its tendency to spring leaks. PEX is flexible and can take moderate freezing without splitting.

Different manufacturers make PEX for specialized purposes, such as in floor radiant heating and for outdoor use, so be sure to purchase a product that meets your needs. PEX installs quickly and easily with specialized fittings and crimp bands and even more easily with push on fittings.

Like CPVX, PEX is not affected by acidic water. However, you should not use it to plumb directly to a water heater, either on the cold or the hot water outlet sides. Plastic and metal have different expansive rates, and such a connection will leak.

For hot water heater installations, use a 12 inch to 18 inch length of ¾ inch flexible stainless steel braided connector to interface the two.

PEX fittings have barbed ends and come in brass and plastic. The plastic versions are made to resist chlorine and acid water, which will corrode copper.

Fittings are available for almost any situation, including water line taps to refrigerators and various types of valves. However, PEX fittings allow only a 90 degree corners, there are no PEX degree fittings. If one is required, you can make it by inserting to male adaptors in a galvanized or brass 45 degree fitting.

Small brass splitters that change the direction of the water flow are available when you need extra taps beyond what a common T fitting will provide.


Use push on fittings to speed installation.

Keep PEX at least 6 inches away from all heat sources, such as hot water heater vents.

Do not plumb directly to a water heater.

Do not make severe turns without an elbow, sharp turns will kink PEX.

Install crimped fittings per manufacturers instructions as most leaks come from improperly crimped fittings.

Crimper must be held at 90 degrees to the pipe.

Crimper jaws must cover all of the ring as it is crimped.

PEX Crimp Rings

PEX pipe is commonly installed using black copper crimp bands. The black colour differentiates the PEX bands, which are no longer allowed by National Plumbing Codes. To crimp the bands, you will need a crimping tool, either a long or short handled model.

Long handled crimpers provide good leverage, which makes crimping easy.

Short handled crimpers can be use in tight locations, where the others won’t fit but the handles on most models are hard to close.

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