How to Install Pex Plumbing

pex plumbing in ceilingDeveloped in the 1960’s, PEX is plumbing tubing that is more formally known as ‘cross-linked polyethylene’. Without blinding you with science, what it means is that a chemical process takes place to create molecules that are more durable under extremes of temperature and chemical attack, making it the ideal material for hot water installations. It is commonly used in the U.S. and many European countries not just for plumbing but also for radiant heating and snow melting applications.

PEX is ideal for use in hot and cold water systems and is even used in refrigeration warehouses and ice skating rinks, very versatile indeed. If you want to install PEX plumbing, you need to first check with your local authority because some building codes have not been amended to include the product.

PEX can be used under slabs and for sub terrain cold water service applications. It is not suitable for outdoor, aboveground use as it needs to be kept out of direct sunlight exposure.

Since PEX plumbing is easy to handle and requires fewer directional fittings, it is easier and quicker to install than other products. That also means less man hours if you are employing a licensed plumber, therefore lower costs. Also, a great proportion of plumbing problems originate at joints but with PEX, there are less places for this to occur in the system.

Joint Systems

PEX is not able to be joined by heat fusion methods or by solvent cements. Joints involve mechanical fittings including two approved standard specifications: ASTM F 1807 (the most commonly used) and ASTM F 1960. There are also insert and outside diameter compression fittings.

How to Install PEX plumbing

Installation is by a crimp-ring system and assists in making tightly sealed connections that are leakproof and permanent. Strong brass fittings are inserted into the end of the PEX pipe and, using a crimp tool with a positive interlocking jaw action, a copper ring is crimped onto the pipe.


It’s important to also have on hand the following tools:
• A cutting tool for even and smooth cutting. Fit the jaw firmly over the piping to make a square cut, free of burrs.
• A crimp ring removal tool will ensure crimp rings and PEX tubing are removed with causing damage to the fitting. After using a crimp ring removal tool, the fitting should be able to be safely reused.
• A flat steel “Go/No-Go” gauge is used to determine if the crimped connection was made properly.

Connecting pipes

    • First, measure and cut the tubing, taking care not to create burrs (a good cutting tool will help prevent these). Improper connections are caused by ineffective tools.
    • Fit a copper crimp ring – not a hose clamp – onto the tubing.
    • Insert the fitting into the tubing, to the fitting shoulder. Place the crimp ring about 1/8" to 1/4" from the tube’s end. Weak connections result from improperly positioned rings.
    • Using the crimping tool, completely cover the crimp ring by the tool’s jaws. Maintain a 90° angle and close the ring completely.

PEX plumbing is easily installed by home owners doing small jobs and using the prescribed methods, but as always, a licensed plumber should be contracted for more comprehensive jobs. Always use quality tools that are in good condition to ensure an efficient end result. Plumbing problems are best avoided in the first place.

photo by pdz house / CreativeCommons