PVC Fittings & Valves

An example of a PVC pipe fitting.

PVC stands for polyvinyl chloride and is composed of natural gas and rock salt in the U.S. PVC is commonly used because of its sustainability, corrosion resistance, flexibility, and low maintenance. The variety of fittings and valves available for PVC also makes it incredibly versatile and compatible with many piping systems.

History of PVC

PVC originated in the late 19th century when scientists exposed the gas, vinyl chloride, to sunlight. However, the discovery wasn't put into use until the 1920s when Waldo Semon developed a synthetic rubber for BFGoodrich. It wasn't until World War II that PVC's properties were fully utilized. PVC was used throughout military ships and as a substitute for rubber insulation in wiring. In modern times PVC is manufactured as a powder and melted down to form pipes and other products.

Type of Fittings

The size of PVC pipe fittings is roughly based on the inside diameter and are sold in 1/4 inch increments. Fittings also have measurements dictating the outside wall thickness. There are eight basic types of fittings: 3 Ways, 4 Ways, 5 Ways, 6 Ways, Side Outlet Wyes, Slip Side Tees, True Wyes, and Manifold Wyes. 2 Way elbow and bend fittings are also used. Each fitting comes in multiple sizes, configurations, and thicknesses.

Types of Valves

There are 11 basic types of PVC valves: Ball, 3 Way, Check, Butterfly, Float, Foot, Gate, Globe, Solenoid, Spigots, and Y-pattern. The most common PVC valves are a two-way Truunion Ball Valve and a Horizontal 3-Way Ball Valve. Like fittings, each PVC valve also comes in multiple sizes, configurations, and thicknesses.

Function

PVC fittings serve two basic functions, to connect intersecting pipes and to change the directionality or angle at which the pipes are situated. For example, a 3 Way fitting connects three separate pipes. An elbow or angle bend fitting changes the direction in which a pipe was going. PVC valves perform the same functions as fittings with the added function of regulating the flow in the pipes. Valves can turn off, slow down, or speed up whatever is flowing through the pipes.

Connecting Valves and Fittings

To connect PVC valves and fittings to pipes two substances are needed, Purple Primer and PVC cement. The purple primer is applied to the inside of the fitting or valve first to ensure glue adhesion. After letting the primer set for a minute, PVC cement is applied over the primer in the same manner. The fitting or valve is then worked onto the pipe a quarter turn at a time until fully secured. Any excess glue should be wiped from the joint and the connected pieces should be held together for a few minutes until the glue has hardened.

References

• Gluing PVC Pipe and Fittings
• Industrial Plastic Valves
• History of PVC
• PVC Fittings