The indoor household plumbing system has gone through extensive evolution in recent decades. In the mid-20th century, the most common material used for these pipes was metals and ceramics which was then replaced by copper pipes due to better properties and easy workability. With rapid advancements in the manufacturing of plastic, it became the primary material for making pipes as plastic is easier to work with, it was significantly cheaper than any metal and it generally had a longer life than its counterparts. There are a lot of different materials used to manufacture plastic pipes, dependent on the applications of the pipes and they can be identified using their color. In this article, details about the most common material used for manufacturing plastic pipes will be presented.
Polyvinyl Chloride or PVC is the most commonly used material for manufacturing plastic pipes and these pipes are used for a lot of different applications in a household apart from the plumbing system. These pipes are generally white in color and most commonly are used for the main water lines for the house. Pipes made from PVC are not as flexible as some other plastics and they warp around 140oF so they are not used hot water or kitchen appliances. The main advantage of PVC, like other plastics, is they do not corrode and are electrical insulators.
The second most common material for manufacturing plastic is chlorinated polyvinyl chloride or CPVC, which is a PVC material that has been through the process of chlorination and is generally grey colored. This allows this material to be more durable to higher pressure and temperature than a PVC pipe. CPVC pipes are more suited for being used for hot water lines and are more flexible than PVC pipes. At lower temperatures, CPVC pipes are prone to cracks so this is the reason they are not suited for main water lines that have to be buried in the ground.
Another common material for plastic pipes is cross-linked polyethylene or PEX which is usually white in color but can also be found in red and blue color. PEX pipes are preferred for home plumbing as they can be used for hot and cold lines. PEX is very inexpensive and flexible so they can fit into a lot of spaces and are easier to work with as compared to other common materials for plastic pipes.