WHAT IS THE DIFFERENCE BETWEEN PVC, CPVC, ABS and other types of pipe?

Generally speaking, the main types of plastic pipe fall into one of the following categories: 

PVC – This stands for Polymerized Vinyl Chloride (unchlorinated); it is a thermoplastic polymer and is generally not approved for potable water. It is biologically and chemically resistant (to most compounds) and is the leading material used in landscape and garden irrigation supply lines, ponds, pools and water gardens.

CPVC – This stands for Chlorinated Poly Vinyl Chloride; it is essentially PVC that has been chlorinated via a chlorination reaction process.  It is also a thermoplastic polymer and is generally non-toxic due to the nature of the manufacturing process.  It is also resistant to many acids, bases, salts, paraffinic hydrocarbons, halogens and alcohols. It is not generally resistant to solvents, aromatics and some chlorinated hydrocarbons.  It is one of the leading materials used in potable water systems for hoe and industry.

ABS – This stands for Acrylonitrile Butadiean Styrene; it is generally suitable for conveyance of potable water, slurries and chemicals, and is also used for chilled water applications and compressed airline systems. 

PP – This stands for PolyPropylene; it is generally used for potable waters, food handling, compressed air lines and for some uses in the pharmaceutical and chemical industries.  It is generally resistant to chemical damage, but is not generally resistant to UV radiation and should be protected when being used outdoors or in moderate to heavy sunlight applications.

PE/PEX – This stands for PolyEthelene.  PE is generally used as supply pipe in commercial and residential irrigation systems and drip irrigation systems.  PEX is simply a cross-linked polyethylene. Through one of several processes, links between the polyethylene molecules are formed to create bridges (thus the term "cross-linked). The resulting material is more durable under temperature extremes, making PEX an excellent material for hot water and other applications. (PEX) is increasingly being used to replace copper and traditional plastic piping for transporting both hot and cold water.