PEX Plumbing 101
Although available for decades, PEX often appears new to homeowners because many municipal plumbing codes have yet to approve its use for residential plumbing. PEX, or cross-linked polyethylene, is essentially a flexible, plastic tube. However, unlike standard plastics, PEX is exceptionally resistant to punctures and withstands both high and low temperatures. While most home improvement stores stock PEX and PEX accessories, you should check with your local building authority before plumbing with PEX. Does this Spark an idea?
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About PEX
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Like standard drip irrigation tubing, PEX consists of a polyethylene plastic. During the PEX manufacturing process, polyethylene molecules become linked, lending PEX the name "cross-linked" polyethylene. The resulting material exhibits resistance to a wider range of temperatures than standard polyethylene, particularly residential hot water temperatures. Additionally, cross-linked polyethylene is more physically and chemically durable than standard polyethylene. Despite its increased durability and temperature resistance, PEX remains flexible and easy to route through structural framing.
PEX Connections
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Unlike traditional water supply piping materials, which usually join via glue-like solvents or soldering, PEX tubing and fittings join only by mechanical joints. The most common type of PEX connection is a crimp sleeve fitting. This fitting consists of a ring that slides over the outside of the tube and a sleeve that slips into the tube's interior. To join the fitting with the tube, plumbers compress the ring with a crimping tool, causing the ring to pinch against the sleeve and create a tight seal.
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PEX Tools
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Cutting tubes and installing fittings are the basic tasks of PEX installation. To cut tube, plumbers typically use a PEX tubing cutter. Like PVC pipe cutters, PEX tubing cutters consist of a sharp-edged blade connected to a pair of hinged handles. As with scissors, plumbers compress the blade over PEX tubing to create a straight, clean-edged cut. Installing fittings requires a specialized crimping tool, simply called a PEX crimper. Like the swaging tools that compress ferrules around metal cable, PEX crimpers clamp over PEX to crush the fitting's metallic ring. Additionally, PEX plumbers use a specialized ring removal tool to loosen and remove PEX connections.
PEX Applications
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PEX is a multipurpose water supply system material. Plumbers install PEX for both hot and cold water lines in residential and commercial applications. Radiant flooring piping is an important secondary application of PEX. In radiant floor systems, hot water pipes run through a concrete slab or other subfloor and radiate heat into the room's interior. While metal supply pipes, such as copper, easily corrode in buried applications and break under the stress of structural movement, PEX remains intact and flexible as a below-ground or underfloor piping material.
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