Plastic pipe fittings have become very popular these days for water supply and drain lines. The low cost, good durability and easy installation has made plastic pipes most popular.
Fittings meant for plastic pipes and for connecting plastic to metal pipes are available in various options like threaded, compression and solvent weldable types. The diameter and specification of plastic pipe fittings also vary depending on their application. For example, fittings with smaller diameters are used for pressure connections and they are slightly heavier and have deeper throats.
Threaded plastic fittings thread almost like metal fittings. When both hot and cold water are to be carried, it is advised to install special transition fittings in order to prevent leaks caused by the different expansion rates of plastic and metals. In fact, plastic pipe fittings are available for almost every kind of application.
- PVC and CPVC: PVC or poly-vinyl-chloride is the most popular material used for making plastic pipe fittings. These fittings are rigid and are connected by thread or solvent weld (glue) connections. PVC pipes come in different pressure ratings and fittings should be chosen accordingly. Standard PVC pipes and fittings are used only for cold water supply and drain line.
- Another variety of PVC called CPVC is ideal for use with hot water supply lines.
- ABS: (Acrylonitrile butadiene styrene) is another variety of plastic widely used for making plastic pipe fittings. ABS can be easily recognized by its black color and rigidity. ABS fittings are usually used for drainage lines and are more economical than PVC pipe fittings.
- Polyethylene: Also known as PE, polyethylene pipe is mostly preferred for hot and cold water supply lines. Polyethylene is generally black or gray in color and is semi-flexible. These pipes are often connected using barb-fittings with clamp rings. However, these fittings can also be heat-fused using an appropriate tool. Polyethylene is mostly used for supply line for lawn sprinkler system, underground loops in geothermal heating, etc.
- Nylon: Nylon is highly resistant to chemical reactions. Because of this fact, nylon is the most popular choice for making pipes used in water lines, and other pipe lines that carry flammable fluids and solvents.