Written by Tom Scalishi | Published at 12:25 PM, May 28, 2021

Answer: This is a very good question, and it is also a question that many DIYers have been asking in recent years. Before explaining CPVC, it is helpful to understand PVC. The term PVC stands for polyvinyl chloride, which is a durable man-made plastic with a wide range of uses. During the manufacturing process, stabilizers are added to help plastics resist oxidation and degradation.

"CPVC" stands for chlorinated polyvinyl chloride. If this seems redundant, there is a reason: the manufacturing process further chlorinates the plastic and changes its chemical composition. If there is no in-depth chemistry course, this can make CPVC more resistant to degradation and extend its service life. However, both PVC and CPVC are popular piping compounds, but they are not completely interchangeable.

Although the names are indeed similar and the two products even look similar, there are some significant differences between CPVC and PVC.

The chemical composition of CPVC makes it more resistant to corrosion and degradation over time than PVC, but it is also more suitable for higher temperature applications. The maximum working temperature of PVC is 140 degrees. Above this temperature, the plastic will soften and lose its shape, causing leakage. However, the maximum working temperature of CPVC before softening is 200 degrees.

In addition, CPVC and PVC react differently to chemicals. CPVC is not only more suitable for chemical applications, the solvents and primers used to bond these materials are also different. Both require specific types.

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It is safe to regard CPVC as a material superior to PVC. Although both are strong, impact resistant and somewhat flexible, CPVC excels in each of these properties.

The manufacturing process makes CPVC resistant to chemicals and degradation, allowing it to last for a long time. This makes it very useful in commercial and industrial environments where chemicals and high temperatures are more likely to be present.

CPVC is also more flexible than cast iron or copper pipe. This flexibility makes it easy to use and helps when encountering joints that are not fully aligned. Its flexibility also makes the product impact resistant, further improving its durability.

Both CPVC and PVC can accomplish many of the same tasks, but CPVC is much more expensive. Therefore, CPVC is mainly used for pipe applications in factories and other places where chemical resistance and heat resistance are important, while manufacturers use PVC in a variety of consumer products.

CPVC is used to manufacture commercial or industrial grade pipes for liquid distribution and the fittings to fix them. These pipes are often used to replace copper or cast iron, and can be used for many of the same purposes. CPVC can also be used as a ventilation duct when necessary, but only for ventilation of air temperatures below 200 degrees.

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CPVC is not a one-size-fits-all product. Although it can be used for pipes of different diameters, these diameters may vary. PVC has a nominal size, called NPS (Nominal Pipe Size). CPVC can provide nominal width and copper tube size (CTS). NPS describes the inner diameter of the pipe, and CTS describes the outer diameter of the pipe.

In addition, CPVC can be used for Schedule 40 and Schedule 80, which describes the thickness of the pipe wall. Although they have the same chemical resistance and heat resistance range, Schedule 40 is thinner than Schedule 80, making Schedule 40 slightly lower in strength, but slightly more flexible. CPVC also has three colors, including off-white, light gray or yellow.

CPVC pipes are not only used in factories and commercial buildings. CPVC works well as a drinking water distribution pipe, making it ideal for residential plumbing applications.

Although there are not many specifications that require CPVC, its durable characteristics make it an excellent choice for residential environments. If there is a reason not to use it, it is the price. CPVC is sometimes six times more expensive than PVC. For this reason, many plumbers and DIYers choose to use it only for hot water distribution pipes and cold water for PVC pipes. Most piping codes can recognize both types.

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