PEX piping is an innovative new product for hot- and cold-water plumbing systems. PEX is the abbreviation for cross-linked polyethylene (PE-X). It's the result of a production process in which links are formed between polyethylene molecules (thus the name "cross-linked"), forming a network of connected molecules. The result is a material that is highly durable and can withstand high temperatures.
      History
PEX piping was first developed in the 1960s in Europe, after technicians from the German company Hoechst discovered that polyethylene (PE) could be used to produce piping that would last for decades. With further development, they were able to safely and economically synthesize an even more durable material composed of a network of interconnected molecules. It was initially called VPE (Vernetztes Polyethylene) but today is known as PEX. PEX piping was introduced into the U.S. markets in the 1980s, and there are now about 10 domestic manufacturers.
      Applications
The first application for PEX piping was for radiant heating used to warm the floors of a chicken coop. It has since been used primarily for in-floor heating systems. In recent times, however, it has increasingly been used for water supply systems as an alternative for traditional piping materials such as steel, copper and CPVC. While these widely used materials are very reliable and relatively easy to work with, the flexibility of PEX piping is making it a more popular choice among plumbers.
      Benefits
PEX piping has some advantages over traditional plumbing systems. It is a flexible, relatively supple tubing that can easily bend around corners and obstacles without the need for joints and elbows. Fewer connections mean a lower possibility of leaks and a faster response time for hot water. It can also be installed much faster, resulting in much lower labor costs. PEX piping is more energy-efficient than piping from traditional materials, because it minimizes the amount of heat lost from the water.
      Durability
As a flexible plastic, PEX piping easily expands and contracts with changing temperatures. This flexibility makes it resistant to potential bursting, even in the event that the pipes freeze solid. Since it has fewer joints and connections, there is less resistance for the water flowing through it. This piping requires very little maintenance and, being plastic, there is no concern for corrosion or pitting.
      Installation
PEX piping is typically sold in long rolls, usually 100 feet long, or in 10 foot-long lengths. Installing PEX piping is just as simple as installing copper -- perhaps even simpler using a few new tools. In particular, it is much easier to make joints in PEX piping. It does away with the hassle of soldering, cementing or using pipe wrenches, which is replaced with the use of crimps. A special crimping tool and crimping rings are used to add fittings in just seconds, error-free.