Pex Plumbing & Pipe
PEX is a common name that is used for cross linked high density polyethylene. PEX is formed into tubing and is most used hydronic application, chemicals transportation and a transportation of sewage and sludge. It has become a strong alternative to PVC/CPVC or copper pipe for use on water pipes.
PEX plumbing has become a visible plumbing type in residential water plumbing because of its flexibility. For example, it can turn 90 degrees by using a wide turn or an adapter, PVC, CPVC or it may require copper elbow joints. It has the ability to run tubing straight from a distribution point and then to the desired outlet without cutting it. What this does is it reduces the need for weak and very expensive joints.
The use of PEX will also lower the cost of materials you will need. PEX is now using PEX with Oxygen Barrier and it is used on Radiant Floor Heating Application and replacing the corrosive copper pipes. One of the best things about PEX is that it makes a good choice for a certain type of progressive replacement of metal and thermoplastic pipes. This is good for the pipes that are used in a long life application so the expected life of PEX is 50 to 200 years.
A good percentage of PEX Plumbing is made from a high density polyethylene or HDPE. Remember PEX has cross link bonds that are introduced into the polymer structure. Cross link is achieved during the extrusion of tubing. The degree that is required by the ASTM standard is 876-93 which is between 65 and 89 percent. Anything higher would cause pipe to break because it would be too fragile.
PEX was first introduced in 1930 by getting rid of extruded tube with an electron beam. In the 1960?s cross linking was perfected by creating a method of peroxide and HDPE before extruding and the cross link was taking place during the passage of the melted substance through a heated die. The process was actually doable in the 1970?s but it was very expensive .
PEX is made and tested with the approval of the national consensus standards the ASTM F 876 and F 877. These products were created separately by a separate third party testing agency. These are tested to make sure they are coded with ASTM and NSF Standards. It has also been approved by HUD for hot and cold drinking water plumbing applications.
PEX is an approved material in all current edition national model plumbing codes. It does have some jurisdiction using older versions of these codes and may not have changed the code to include PEX tubing.