Cross-linked polyethylene pipe or more commonly referred to as PEX tubing is now the typical option for potable and hydronic radiant heating systems. Due to its high percentage of usage within the plumbing industry, many distribution companies have created an assortment of different types of fittings in which PEX can be connected to. Each type of fitting specializes in a different range of application, and connection methods. The most popular fittings used today are crimp style PEX fittings, followed by Push-Fit, Press, Expansion, and compression type PEX fittings.
Type of materials:
Crimp fitting are installed with a PEX crimp tool by causing a 360 degree compression while the crimp ring is properly positioned on the tubing.
Clamp fittings are installed by a PEX clamp tool. The process is started with the ring being properly placed over the PEX tubing, allowing the user to grasp onto the ear of the clamp ring and press down, tightening the connection securely.
The push-fit fitting are designed to be used without any tools. They come equipped with a built in mechanism that allows the PEX tubing to be pushed into the fitting to make a tight and secure connection. These fittings are compatible with all types of PEX and usually come in brass or poly.
These fitting are installed without any tools to provide a secure connection. Simply insert the tubing inside of the fitting until it is firmly in place. No more work has to be done. In order to remove the fitting a special tool must be used. At the bottom of this page are the ASTM (American Society for Testing and Materials) standards and their full descriptions as listed by the ASTM.
Another type of fitting commonly used for PEX connections is compression type. This fitting can be connected to all types of PEX tubing including PEX-Al-PEX. This fitting utilizes the compression method to connect the PEX through an O-ring, and can be installed without using any PEX tools.
Compression PEX fittings are installed by sliding the brass compression nut over the tubing followed by the compression sleeve (O-ring). The next step is connecting to the fitting and tightening your compression nut by hand at first, then finishing with a wrench or nut driver.
Press PEX fittings are installed with PEX press tools and press sleeves. This fitting are used through the insertion of a sleeve into the PEX tubing allowing a tight and secure fit onto the fitting. These fittings are sold for all types of PEX tubing, including PEX-Al-PEX.
Press fittings are installed by simply placing the fitting which has a mechanism already installed onto the tubing. Then a PEX press tool corresponding to the size of the fitting is used to make a secure connection.
Expansion PEX Fittings
Brass or poly expansion fittings are unique in their method of connection, only allowing connection once the PEX tubing is expanded using a PEX expansion tool and ring. They are only applicable with PEX-A (Engel method) tubing, and meet the standards of F1960 and F2080 set by the ASTM.
Expansion fittings can only be installed with a PEX expansion tool. This tool is used to expand the tubing until it has reached the point in which a fitting will properly be placed and secured within the tubing. The tubing then retracts making a secure connection around the fitting.
Watch our video about PEX plumbing tools