In the old days plumbers had to work with messy (and heavy) cast iron pipes to run water and and drain pipes in a home. Then, copper replaced cast iron and was the material of choice for a number of years (primarily up to the 1970's), but while copper was easier to work with than cast iron, it was still inflexible and heat was required to join pipes and fittings. During the 1970's plastic pipes that were light an easy to join (no heat required) were developed, making plumbing a much cleaner and less labor intensive trade.
Nowadays, plastic pipes made from materials cush as PVC (poly vinyl chloride), CPVC (Chlorinated Poly vinyl chloride), ABS (Acrylonitrile-Butadiene-Styrene so ABS for short), PB (poly butylene) and PEX (cross linked polyethylene) have essentially replaced cast iron and copper and are the material of choice in new construction. That's a lot of different letters so, if you're wondering what the differences are between all these plastic pipes and how you can tell them apart, here's a quick primer on plastic pipes.
- PVC is the most commonly used plastic pipe in home construction today. It's light, inexpensive and easy to work with so plumbers love it. Homeowners love it as well since it's resistant to corrosion and temperature changes and will never rot, so it can be used in water systems, underground wiring and even sewers.
- PVC is white in color and can be used in all kinds of applications since it's available in a wide range of diameters from 1/8" all the way up to 24" and possibly even beyond.
- The pipe comes in three grades, schedule 40, 80 and 120. Schedule 40 (the lightest grade) and schedule 80 are commonly used in residential construction, while schedule 120 is primarily for industrial high pressure applications.
- Is PVC pipe with chlorine added during in the manufacturing process to increase the pipe's strength strength.
- CPVC is primarily used in industrial applications.
- This pipe is easy to recognize because it's black in color. It has similar characteristics to PVC pipe (resists corrosion, won't rot, can handle temperature changes), but it less flexible than PVC so is less commonly used in new construction.
- In some areas of the country building codes no longer allow ABS pipe to to be used in new construction.
- Was commonly used for hot and cold water systems during the early 1980's primarily because it was easier to work with than copper pipes however, inmost new construction PB pipe is now being supplanted by PEX tubing. You can recognize it by it's gray color.
- Is the newest type of plastic pipe used in construction. Developed in Europe in the 1970's and only introduced into the US in the 1980's PEX has quickly become extremely popular.
- PEX is light, extremely flexible (it can be run right through studs the same way as electric cables) making it easy to install.
- PEX is also resistant to heat and cold and easy to work with. Simply cut it to length with a utility knife and join runs by clamping them together with a PEX clamp (no heat required).