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Before we talk about PEX fittings a bit about What is PEX?
PEX is cross linked or polyethylene (polyethylene cross). It is very flexible plastic tubes consisting of individual molecules which are constantly connected to each other and respectively are very strong and that will not change or melt. No corrosion, freezing damages or abrasion ever been noticed in PEX tubing. High energy efficiency with low heat loss of water.
The first PEX tubing material was presented back in last century 30s. In those years it was very expensive. In 70s-80s new methods like Engel cross-linking and Sioplas process where patented and producing of PEX tubes became much more cheaper and popular. Not so long time ago PEX tubing become as alternative to CPVC (chlorinated polyvinyl chloride), PVC or cooper tubes and pipes for use in buildings and other residential water pipes.
It’s shortly about wonder PEX. Tubes are really great. It can be used for underground cold water services or used up to 200° Fahrenheit (93° Celsius) for heating or 180° F (82° Celsius) limit for plumbing.
No any tubing or piping without its fitting can exist. PEX fittings are used to make PEX to PEX connections, to connect PEX to a manifold and to connect to another material. There are different Heat Fittings can be used.
PEX tubes could be mounted using only mechanical fittings no any glues, solvent cement or heat fusion to be used for PEX fittings.
There are couple of approved standard specifications for PEX connections: ASTM F 1807 and ASTM F 1960. Both are mechanical insert fittings. The crimp fittings specified in ASTM F1807 are the most common used. Insert and outside diameter compression fittings, are also available.
PEX fittings generally are easy to install and obviously decent amount of time and money can be saved using this material.
One of fitting method is Expansion.
Use special expansion tool to increase the diameter of tube. Insert tool in PEX tube, expand it after tube shrinks back and shaping around the fitting and fix with a plastic ring.
Other one is stainless steel clamp or SSC method.
SSC fastens tube with scrimping tool to tighten the clamp around PEX and fitting.
And I almost forget about standard connection method.
Insert cooper crimp ring over PEX pipe.The copper crimp ring is inserted over the pipe and fitting is inserted inside the tube. Crimp ring over pipe use PEX crimping tool. The fitting is inserted inside the pipe, and the copper ring is crimped over the pipe and fitting using the PEX crimping tool.
When selecting PEX fittings it is important to match the size of PEX tubing to the size of fittings. With PEX to Copper or PEX to Thread transitions, always connect the PEX part of the fitting last. If it is a sweat connection, cool off the fitting prior to connecting it with PEX pipe.
Main PEX fitting materials are brass, bronze, copper and engineered plastic fittings for PEX. General tools to work with PEX tube fittings are crimping tool, pipe cutter and a de-crimping tool. There are ½” or ¾ ” crimping tools. De-crimping tool is as stated, to remove the crimp ring.
When you looking to purchase PEX fitting tools the smarter choice is to buy all tool kit together, prices will be significantly lower.
In conclusion, when we look and compare pros and cons for PEX tubing with PEX fittings it is coming clear that that advantages over metal and rigid plastic systems are more than cons-easier to install, resistance to corrosion and longer life are just main some of reasons to use PEX fittings.
