PVC pipe and CPVC pipe are two types of plastic pipe material used today for plumbing systems. The difference between PVC pipes and CPVC pipes are the chemical composition of the pipes: PVC is polyvinyl chloride and CPVC is chlorinated polyvinyl chloride. Both materials are commonly used in residential plumbing and commercial plumbing but have different applications.
CPVC vs PVC Pipe Comparison and Differences
Both CPVC and PVC share these properties:
- Lightweight
- Rigid
- Inexpensive
- Easy to Install
- Corrosion resistant
- Impact resistant
- Chemical resistant
PVC pipes are temperature limited as the plastic starts to deform above 140°F (60°C). CPVC pipe deforms at higher temperature of 200°F (93°C) so it can be used in potable water plumbing for hot water lines.
Another difference in CPVC pipe is that is typically sized in copper tube sizes (CTS) where PVC pipes are commonly sized in iron pipe sizes (IPS). In CTS, pipes are measured nominally from the outside where IPS are measured from the inside. For example, a 1/2″ CPVC pipe will be smaller in diameter than 1/2″ PVC pipe.
Typically, PVC pipes are colored white or light grey where CPVC pipes are colored ivory or off-white. Both PVC and CPVC pipes are sold in 10 ft lengths called “sticks” but can be sold for shorter or longer lengths. Both pipe materials come in various wall thickness sizes such as Schedule 40 and Schedule 80, with Schedule 40 being the most common.
Applications of PVC and CPVC pipes
PVC pipes and CPVC pipes have many plumbing applications. PVC pipes often are used in water distribution for cold water lines or in drain, waste or vent (DWV) systems. For example, PVC can be used for lawn sprinkler systems as it is inexpensive, impact resistant, and corrosion resistant. PVC is also used for drains impact resistant and chemical resistant. Since PVC is IPS, different wall thicknesses of CPVC
CPVC pipes are used in high temperature water distribution such as hot water and temperature relief valves on water heaters. Since CPVC pipes are copper tube size, CPVC is used for indoor, potable water plumbing.
CPVC is also fire sprinkler systems as an alternative to steel piping. While limited to residential or light-use facilities, it does not corrode compared to steel and is less expensive and lighter weight to install. CPVC used for fire sprinkler systems is not the same as CPVC for indoor plumbing and should not be interchanged.
CPVC for Fire Protection Systems
PVC Pipe and CPVC Pipe Installation
PVC pipe and CPVC pipe have pretty similar installation. As plastic pipes, can be cut by a saw or sharp blade and are glued together. Some PVC pipes come with a bell end, which is wider opening to accept a plain end or standard end. Typically, larger diameter (greater than 2″) PVC pipes have bell and plain ends so that long runs of pipe can be easily installed. All PVC pipes and CPVC pipes are connected together with fittings which are essential in piping systems.
To install is important to measure out the distance between fitting socket and fitting socket. Fittings and pipe ends need to be clean. Both the fitting socket and pipe need to be primed and solvent cement applied to both ends. Set inside pipe end inside the fitting until alway the “home”. Wait for it to cure before pressure testing.
Some solvent cements work with both PVC and CPVC and can be used for both materials. Other cements only work for one type of material and should only be used for that material. Its best practice to check the solvent cement and primer for the manufacturer’s application.
Final step for installation is pressure testing. Even with properly installed pipes, pressure testing is usually required by plumbing code and is a good practice to ensure no leaks or breaks. Typically, low a low PSI air test is used with a liquid detector or as a timed pressure hold to confirm no leaks. Different jurisdictions and applications will vary so always consult with a professional plumber or the inspector for clarification.
Further Information
To learn more about PVC, CPVC, or any other plumbing materials, check out other articles.