Difference Between CPVC and PVC

Most of us are aware of PVC, which is a widely used plumbing material in construction and drainage. It stands for Polyvinyl chloride, and is one thermoplastic polymer that is abundantly used all over the world for plumbing purposes. It is cheaper than GI pipes and offers flexibility to those involved in plumbing works as it can be easily assembled. Of late, another polymer has made inroads into construction and drainage systems that has emerged as a better product under certain circumstances than PVC. It is CPVC, or Chlorinated Polyvinyl Chloride. Not many know the differences between CPVC and PVC, and this article intends to highlight the features of both CPVC and PVC to enable people to make a better choice depending upon their requirements.

What is CPVC?

Essentially, CPVC is nothing but PVC that has been subjected to a process known as chlorination. This chlorination takes place through a chemical reaction called free radical chlorination that makes use of thermal or UV energy. This energy changes chlorine gas into free radical chlorine that reacts with PVC and replaces some of the hydrogen from PVC in the process. Though CPVC retains and shares most of its properties with PVC, this chlorination makes it fire retardant and the ability to work in conditions where temperatures are in the vicinity of 200 degrees Fahrenheit. It also develops excellent corrosion resistant properties making it suitable in conditions where there is danger of corrosion and PVC pipes cannot withstand. CPVC has a smoother internal surface which implies it can be used to transport liquids for a greater distance without encountering problems of pressure loss, scaling or pitting. CPVC is also ideal in carrying hot and cold water which is why it is being preferred in liquid heating installations


PVC has been widely used in plumbing activities ever since its invention as it is cheap, flexible and can be molded in various shapes and various fixtures are available for a plumber wherever there are severe bends and curves. PVC can always be made softer by adding plasticizers whenever there is such requirement. PVC does not easily react with acids and bases and is thus most suitable for drainage.

There are certain conditions where it is prudent to stick with PVC such as when aqueous ammonia or hydrochloric acid is transported from one place to another. In all other situations, CPVC can be easily used in place of PVC. CPVC is also resistant to salts and aliphatic hydrocarbons. The properties of CPVC are dependent upon the amount of chlorination and the type of additives used. It is therefore seek advice of the manufacturers before installing CPVC to ensure it suits your requirements.

Difference between CPVC and PVC

• While PVC is the most widely used thermoplastic polymer, CPVC is a recent phenomenon created by chlorination of PVC

• PVC is still more popular than CPVC which is more expensive

• CPVC is better suited under certain conditions such as transport of hot and cold liquids

• CPVC is resistant to corrosion and has a smoother internal surface than PVC

• CPVC also has higher tensile strength and is more ductile than PVC.