PEX Tubing Installation - How to Install PEX Tubing

PEX is formed from a chemical called polyethylene that consists of cross-links. Links connecting polymer chains are called cross-links in the chemistry terminology. This chemical structure of PEX makes it extremely suitable for tubing that is used in radiant heating systems and for insulating high tension electric cables. Insulated PEX tubing ensures high performance even in the most extreme conditions and environments. More recently, PEX has started replacing Polyvinyl Chloride(PVC) and Chlorinated Polyvinyl Chloride (CPVC) for tubing in water pipelines. PEX is the obvious choice for many such applications as it is robust and has better capacity to perform optimally even in high temperature conditions. Plumbing with PEX tubing is also convenient as PEX is highly resistant to corrosive chemicals that are usually present in a typical plumbing environment. PEX tubing repair is also easy thus making it more desirable for diverse tubing applications.

How to Install PEX Tubing

The following procedure demonstrates the installation of PEX tubing for water lines.

Step 1: Measure the length of PEX tube that is required for the water pipe. Cut a PEX tube of equal length from the main PEX tube using a specially designed PEX tubing cutter. Ensure that the cut is made without causing any protruding edges on the surface of the tube. To avoid the formation of such rough edges, hold the tube straight while cutting it.

Step 2: Now insert a copper crimp ring into the pipe. After that, insert the PEX tubing into the fitting of the pipe. The PEX tube should be inserted in such a way that the tubing bottoms out at the shoulder of the fitting.

Step 3: Now shift the copper crimp ring upwards so that it is at a distance ranging from 0.125 inches to 0.25 inches from the tubing.

Step 4: Hold a ring crimper at an angle of 90 degrees to the copper crimp ring. Bend the crimp ring by closing the the ring crimper completely over it. If the crimper is not at an angle of 90 degrees, it might lead to an uneven cut and even cause the plastic to dent. Also, if the crimper does not entirely cover the crimp ring, it might result in a non-uniform crimp which will eventually lead to a situation where the tubing is unable to cover the ribs of the fitting.

Step 5: This step involves the Go-NoGo gauge test. The Go-NoGo tool is used to check the acceptable tolerance levels of the particular work piece under test. As the name suggests, the tool has to check if the work piece qualifies the test, indicating Go and fails the other one indicating NoGo.

The Go gauge, in this case should be capable of sliding easily through the fitting while the No-Go gauge must not be able to pass over the fitting. In case the No-Go gauge manages to slide over the fitting, it indicates that the tubing was not cut properly. In this case, the tubing must be cut again as described in the steps above.

Step 6: PEX has a tendency to contract by about one inch for a temperature change of 10 degrees Celsius. These one-inch contractions are usually located after every 100 feet on the pipe. The PEX tubing installation should be done in such a way that it is able to accommodate these contractions of the pipe.

To cater to this problem of contractions, create a loop in the PEX, which is about 8 times the diameter of the tubing. Employ straps and hangers to support the PEX at every 32 inches, if the tubing is installed alongside a joist and at every 6 feet if the tubing is supported by a beam. In case of a vertical installation of the pipe, support should be provided at every floor. However, it should be ensured that the support hangers are loose enough to allow the movement of the PEX.

Thus PEX tube installation is quite an easy process and the next time the plumber is busy installing one in your locality, you will surely be in a position to supervise his work, if not teach him a thing or two.