Plumbers use plastic pipes to construct water supply systems and drain systems. Each type of plastic plumbing pipe handles a different range of temperatures and water pressures. Manufacturers stamp pipes with labels that indicate the pipe's diameter, pressure ratings and plastic type. Understanding the applications, characteristics and appearance of the different types of plastic pipes will help you determine the proper pipe for your plumbing project.
Polyvinyl Chloride (PVC)
Plumbers and landscaping professionals use PVC to construct outdoor water supply lines, such as buried, irrigation systems, and waste water lines, such as under-sink P-traps. Many do-it-yourself plumbers are familiar with PVC as the white, plastic pipe available in hardware and home improvement stores. Plumbers joint separate lengths of PVC pipe with threaded or smooth fittings. Smooth fittings, called "slip" fittings, connect via a chemical welding process called "solvent welding" that resembles gluing.
Chlorinated Polyvinyl Chloride (CPVC)
The chlorination of PVC piping makes the material suitable for use among residential, potable water supply lines. However, plumbers must check building codes prior to installing CPVC in residential applications, because many municipalities prohibit the use of CPVC for residential water supply. CPVC withstands high temperatures and some manufacturers produce CPVC for fire sprinkler applications. Like standard PVC, CPVC components connect via solvent welding to threaded fittings. Because CPVC appears in greenish-blues, reds or with stripes, the most effective way to identify the pipe is by reading manufacturing stamps.
Acrylonitrile Butadiene Styrene (ABS)
ABS plastic pipes are an easy to install and inexpensive alternative to metal drain pipes. Do-it-yourself plumbers will recognise ABS pipes as the large-diameter, black pipes found in a hardware store's plumbing department. Plumbers use ABS pipes to construct drain, waste and vent systems. ABS is suitable for buried applications, such as residence to sewer treatment lines. Although ABS pipes typically connect via solvent welding, some applications call for flexible, rubber fittings.
Cross-linked Polyethylene (PEX)
Many familiar products consist of polythene plastic, such as plastic bags and packaging. A manufacturing process permanently links polyethylene's molecules and transforms the plastic into a flexible tubing called PEX. Unlike rigid plastic pipes, flexible PEX does not require 90-degree elbow fittings to make turns. PEX fittings connect via solder and glue-free compression fittings. PEX withstands high temperatures and is suitable for both hot and cold water supply. Plumbers bury PEX, embed PEX within concrete slabs for radiant flooring and run PEX through wall framing for residential supply systems.