PEX Crimp Fittings vs. Expansion PEX Fittings

PEX Crimp Fittings vs. Expansion PEX Fittings

PEX Crimp Fittings vs. Expansion PEX Fittings

PEX tubing, also called crosslinked polyethylene, is a popular piping material for residential hot and cold water. Plumbers choose this piping material based on the fact that it’s corrosion resistant, lightweight, very bendable, easy to join, and competitively priced. In fact, PEX is the newest and fastest-growing material in common use for supply piping today. However, the effectiveness of the piping itself is also dependent upon the technique used to connect the tubing together. Two popular connection methods include PEX crimp fittings and expansion PEX fittings.

Pipe fittings are components of a piping system that join the sections of pipe together. While commonly made of brass, this solution also comes available in plastic, bronze, and even stainless steel. PEX fittings are available in many different connection methods which vary from manufacturer to manufacturer. Common solutions would include the following:

  • Crimp fittings (most common)
  • Push-fit or push-to-connect fittings
  • Expansion fittings
  • Press Fittings (A.Y. McDonald Press Fit Fittings are not compatible with PEX)

While the features, benefits, and connection process of press fittings and push-fit fittings are self-explanatory, those new to the industry may not quite grasp the differences between PEX crimp fittings and expansion PEX fittings. Continue reading to learn how these two methods compare and what makes their installation processes stand out:

PEX Crimp Fittings

Expansion PEX Fittings

  • Brass fittings must conform to ASTM F1807 standard while plastic fittings conform to the ASTM F2159 standard
  • Installation requires the use of a crimping tool
  • Testing of the connection can occur immediately after installation
  • Tools require calibration with the use of a special go-no-go gauge
  • Compatible with all PEX tubing types (A, B, C)
  • Readily available
  • Not all crimp tools work well in tight spaces
  • Fittings must conform to the ASTM F1960 standard
  • Installation requires the use of an expansion sleeve
  • Testing of the connection must take place 24 hours after installation
  • Can be used only with PEX-A tubing
  • Generally only sold to trained, professional plumbing and HVAC installers
  • Temperatures can affect the number of expansions needed for a fitting


PEX Crimp Fittings Installation:

The standard method for connecting PEX pipe to PEX crimp fittings uses a crimp ring and a PEX crimping tool. The crimp ring is inserted over the pipe, the fitting is inserted inside the pipe, and the ring is crimped over the pipe and fitting using the PEX crimping tool. One common PEX crimping method is the Oetiker style.

When connections are done properly, PEX crimp fittings should be a relatively fast and inexpensive way of connecting PEX. This technique has been in the industry for a long time and considered the most common connection method. There are many different tools and crimp ring manufacturers, making these parts easy to purchase at a variety of suppliers.




Expansion PEX Fittings Installation:

The expansion PEX fittings installation process includes first sliding the PEX-reinforcing ring over the end of the pipe. Most rings should have a stop on the end of it but, if they don’t, a small space has to be left at the end of the ring before starting the connection. Using an expansion tool, the pipe will expand per the manufacturer’s instructions. This should be done until the pipe is expanded wide enough to receive an F1960 fitting. The fitting must then be inserted into the pipe until the shoulder of the expansion ring touches the shoulder of the fitting.

The installation process for expansion PEX fittings is a completely visual connection, unlike other types that require tool calibration or go-no-go gauges. The fittings have virtually the same inside diameter as the pipe, creating less restriction and often allowing for smaller pipe sizes. This connection method is impossible to dry-fit and tools are one size fits all, with the exception of the expansion heads, which need to be changed out for different pipe sizes.


Now that you’ve been schooled on the topic, test your knowledge by taking our PEX Crimp Fittings vs. Expansion PEX Fittings AYU course. For information on A.Y. McDonald’s product offerings, fill out our contact form or call Customer Service at 1-800-292-2737.