What is CPVC Pipe?


Chlorinated polyvinyl chloride pipe, more commonly known as “CPVC pipe,” is a plumbing material made of highly durable thermopastic. It is the most commonly used piping in building construction in most parts of the world, outpacing ordinary polyvinyl and metal and copper alternatives. Builders often prefer it because it is very durable, resists corrosion, and has very high temperature thresholds. This makes it safe for supplying water, gas, and oil, and it can also mean energy savings for homeowners and businesses. The biggest drawbacks usually have to do with cracking, and some people also complain that drinking water carried through these pipes has a somewhat plastic taste, particularly when the pipes are new.

CPVC piping comes in many different forms to perform various functions.
CPVC piping comes in many different forms to perform various functions.

How They're Made

These sorts of pipes often look like they’re made of ordinary plastic, but in most cases their manufacturing is somewhat complicated. Chemists usually begin with the polymerization of the vinyl chloride monomer, which is a molecule that forms the basis of many plastics. Through a series of reactions they then use thermal energy or ultraviolet rays to decompose the chlorine ions, which can displace hydrogen molecules.

CPVC plumbing is used in the majority of modern construction.
CPVC plumbing is used in the majority of modern construction.

The end result is a material that is durable and tough. From the outside it looks a lot like regular polyvinyl chloride pipe, or PVC pipe, and it shares many of that precursor’s traits when it comes to malleability and general usefulness. It is stronger and more resistant to leaks and energy loss, however. PVC was the industry standard in most places until the mid-1980s, when the CPVC alternative became more widely produced and accepted. Installation is safer and faster, requiring only a special solvent cement as opposed to the torch and solder that are usually required for metal piping. CPVC options generally last longer, too, and tend to be less susceptible to failures.

Some people with CPVC pipes say their water has a plastic taste.
Some people with CPVC pipes say their water has a plastic taste.

Heat Tolerance

One of the biggest benefits of CPVC piping is its ability to tolerate heat. It is generally capable of withstanding corrosive water temperatures between 70°F and 90°F higher than its PVC counterparts, which makes it a good choice for carrying hot water and industrial liquids alike. For hot and cold water applications, it is typically rated at 100 pound per square inch (psi) at 180°F and 400 psi at room temperature. It is also fire resistant and will not burn without a flame source, making it suitable for fire suppression systems in light hazard and residential settings.

CPVC piping is surpassing copper fittings in popular among modern builders.
CPVC piping is surpassing copper fittings in popular among modern builders.

Chemical Corrosion Resistance

CPVC is also generally non-toxic, which means that it won’t leach chemicals or corrosives even if they’ve been sitting in the pipe for some time. It’s immune to galvanic corrosion and resists scale build up, which is important where water purity is concerned. It is also resistant to chemicals and durable against their residues. Being plastic, it is not subject to electrolysis, the process through which water breaks down into oxygen and hydrogen gas.

Energy Savings

Homeowners and businesses often like this sort of piping because it can sometimes save money on heating and cooling costs, at least where liquid temperatures are concerned. It has pretty good insulation, which means that it keeps hot water hot and, conversely, cold water cold. Gasoline and oil often flow really well through these sorts of pipes, too, which can promote greater efficiency and in some cases means that building owners will use less.

Common Drawbacks

There are concerns with the use of this piping, however. Some people who receive drinking water through CPVC pipes complain of a plastic taste in the water. The pipe and fittings are also subject to cracking if they’re dropped, and they can sometimes warp or break if a house’s foundation shifts dramatically or, as is more common in some places, during earthquakes. Despite their great resistance to temperature shifts internally, they can sometimes expand with temperature change externally. Freezing conditions can sometimes mean that these pipes will burst, for instance, which can create a major problem. There have been some documented cases of bacteria growing inside the pipe as well, often in cases where the pipes are rarely used.

CPVC pipes require a special cement for sealing joints.
CPVC pipes require a special cement for sealing joints.

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Discussion Comments


Do I need heat tape on cpvc water lines under a mobile home or will insulation be enough?


Can I use cpvc pipes for water lines at a terrace, exposed to sunlight?


CVPC pipes are the most needed part of the plumbing industries. The pipes are resistant to corrosion and chemicals as well. These pipes can be used for both hot water and cold water pipes.


Can I use cpvc underground?


What is the line tested pressure?


Which material is used for jointing purposes?


What is the maximum flow pressure with stand capacity?


What is the maximum heat resistance capacity?


Can i use CPVC pipes for LPG (liquid petroleum gas). For domestic kitchen underground pipes for approx 10' length.


use Mseal to stop the leak.


just replaced the water lines in my house with cpvc. what can you do to get rid of the dripping noise when you turn on the hot water?


are these CPVC pipes resistant to sunlight / uv. what is the life expectancy for upstream / downstream piping in an apartment building of seven stories. can anyone comment please.


You must remove and replace it. It is very simple. First, shut off the hot water supply and relieve the pressure by turning on the faucet. Next, use tubing cutters to cut the pipe as close to the elbow as possible (have a bucket under to catch remaining water). Next, clean the ends of the pipe and the new elbow with pipe cleaning solution. When it dries, apply cpvc glue to either end of the pipe and inside the new elbow, enough for coverage, but not excessive. Finally, replace the new elbow and wiggle/roll the fitting/pipes to ensure a good seal and fit. Hold it still for a minute or two, and you've finished. Be sure to read the label for cure time, some glue needs several hours to set.


joint leaking (hot) cpvc pipe. what do I use to stop the leak?

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