Since more than 50 years ago, plumbing applications all over the world have used CPVC (chlorinated polyvinyl chloride), a robust and long-lasting material.
CPVC is an excellent material for residential, commercial, and even industrial piping and fire sprinkler systems due to its inherent chemical resistance, dependability, and capacity to withstand high heat and pressure. It was first developed by Lubrizol Advanced Materials.
What is CPVC?
Consider CPVC to be a cousin of PVC. Despite having many similarities, they shouldn’t be used interchangeably. With one exception, both are constructed from the same fundamental components. A free radical chlorination reaction changes CPVC by actually raising the material’s chlorine content. Another thermoplastic used to make many of the same products as PVC is CPVC.
CPVC can withstand a wider range of temperatures thanks to this difference in composition. For use in hot water applications, CPVC is frequently required by building codes rather than PVC. PVC can be used in applications with temperatures no higher than 140 degrees Fahrenheit according to ASTM standards.
The material may soften and the joints may become weaker at temperatures above this. On the other hand, CPVC is able to withstand temperatures of up to 200 degrees Fahrenheit.
PVC Vs CPVC
PVC pipe is likely something you’re familiar with. It is the common white plastic pipe used for drainage and plumbing. PVC, or polyvinyl chloride, has increasingly replaced metal piping. One of the most widely used plastics in the world, PVC is known for its strength, longevity, simplicity of installation, and low price. To make pipes, fittings, valves, and other supplies for handling liquids, PVC, a thermoplastic material, is molded into various shapes.
Other Differences Between PVC & CPVC
The two materials also differ in a few other ways. The majority of PVC pipe in North America is Nominal Pipe Size (NPS), whereas Copper Tube Size (CTS) or NPS standard sizes are both available for CPVC.
The copper tube sizing system, which as its name suggests is the same system used for copper tube pipe, is completely different from Nominal Pipe Size.
Consider your intended use and the sizing system you’ll need before making a CPVC purchase. Color itself is sometimes a clue. Schedule 80 CPVC (NPS) is typically a light gray color, whereas CTS CPVC is frequently a light yellowish color.
PVC pipe and fittings are typically available in white or dark gray. To be certain, always look at the manufacturer’s printing on the pipe.
PVC and CPVC occasionally need different primers and solvents to connect pipe and fitting joints due to their different chemical compositions.
The ability of the cement to chemically soften the plastic is necessary for the formation of a strong joint. Because of this, you should always use a cement made for the material you’re working with.
Applications of PVC & CPVC
CPVC is better suited for hot water applications up to 200F, as was previously mentioned. Although CPVC is now widely used for both hot and cold potable water, PVC is still frequently used for vent and drainage systems, as well as for unheated water.
CPVC can be used in commercial and industrial settings due to its more durable qualities. CPVC is typically more expensive than PVC due to the greater variety of applications it has. Nevertheless, it continues to be a very affordable and adaptable material.
PVC is ideal for drainage, vent, and cold water systems, as well as recreational use and building. Applications where the maximum temperature will exceed 140 degrees Fahrenheit but not exceed CPVC’s maximum rating of 200 degrees Fahrenheit are advised to use CPVC.
The chemical make-up of the media being handled in your application is another consideration when choosing a material. Despite the fact that PVC and CPVC are both resistant to many of the same chemicals, some can only be handled by one or the other.
To make sure the piping materials you select will work with your specific application, consult a chemical compatibility chart.
Can PVC & CPVC Be Used Together?
Although all NPS size pipe and fittings will fit together, it is not advised to mix and match different kinds of materials. The pipe line’s capacity for pressure and temperature may be compromised by mixing materials. The construction of any pressurized pipe system using compatible piping materials and schedules is, therefore, always advised.
Common CPVC and PVC Product Types
Both PVC and CPVC resin start out in either a powder or pellet form, frequently with the additives already blended in. The finished products used for domestic, commercial, and industrial use are then shaped or molded from the resin.
For PVC and CPVC, there are two main molding techniques.
- Injection Molding: Injection molding is a simple and repeatable process for large-scale production. The resin is injected through the mold tool after being fed into a heated barrel, and it is then cooled to harden.
- Extrusion: Extrusion begins when the resin is fed in at the top of the machine and is also a process for high volume products. Through the mechanical energy of a turning screw and the use of heaters along the barrel, the raw material is gradually melted. After that, it is shaped into a continuous profile and cooled to set.
Pipe, Fittings and Valves: Pipes and fittings account for 62% of PVC sales, according to a 2016 market report. It is an advantageous replacement for other materials due to its simplicity of installation and resistance to corrosion. When heat, pressure, or chemical resistance are issues, CPVC is frequently specified for pipes, fittings, and valves.
Ducting: The demand for dependable fume handling systems, especially in corrosive environments, is rising quickly as a result of tighter air emission regulations. Both PVC and CPVC are specified in applications where dependability is required depending on the requirements, primarily temperature.
Sheet and Lining: CPVC has excellent fire and corrosion resistance, and it can be used in a variety of industrial applications and covered in Fiber Reinforced Plastic (FRP). Additionally, PVC can be specified when the sheet or liner will be subject to lower temperature and pressure demands.
Other product types: Fabricators can cut and form the material for use in a variety of varying applications by starting with CPVC or PVC sheet as a base.
Why CPVC is Ideal for Residential Plumbing Systems
Following are just a few of the reasons why homes around the world trust CPVC pipe and fittings:
Safe, Clean Water Quality: Materials for use in applications requiring potable water are tested and approved by significant international organizations like NSF International. These certifications provide assurance that a CPVC potable water system does not introduce any potentially harmful or dangerous materials into the drinking water it transports. For example, FlowGuard CPVC is approved for use in all potable water systems and doesn’t contain plasticizers, flame retardants, biostabilizers, or anti-static agents.
Joint Strength: Solvent cement is used to connect CPVC pipe and fittings together. A substance known as solvent cement is used to moltenly chemically fuse a pipe to a fitting. Solvent cemented joints, in contrast to glue used in other piping systems, become the system’s strongest component and, when installed correctly, don’t disintegrate.
Chlorine Resistance: Pipe failures in PPR (green pipe), PEX, and metallic pipes can be brought on by chlorine-based disinfectants, particularly chlorine dioxide. The additives used to keep your water clean and safe, however, ensure that CPVC is unaffected by the chlorine and will never break down.
Biofilm Resistance: Water distribution systems are ideal for bacterial growth, but CPVC helps to keep water pure. In terms of its capacity to thwart the development of biofilms, CPVC consistently outperforms copper and all other plastic piping materials, particularly PPR, according to a number of international studies.
Fire Resistance: CPVC is noncombustible and resistant to fire. To put it another way, unlike other plastics that can ignite and keep burning even after the fire’s source has been extinguished, CPVC won’t aid in the spread of a fire. Thanks to its low flame and smoke development characteristics, FlowGuard CPVC received the highest fire classification rating attainable for a non-metal product.
Which One Should I Choose: PVC Or CPVC?
Where PVC is used, CPVC can be used safely. Potable water, such as that used for bathing, drinking, and cooking, may be transported using PVC or CPVC, but only plumbing that has received ANSI / NSF 61 certification ought to be used. Both CPVC and PVC are chemically resistant and largely resistant to degradation from acids, alkalis, and most organic chemicals. But in order to stop sun-related degradation of both materials, UV stabilizers must be used or they must be buried.
In plumbing applications, CPVC and PVC pipes are more affordable, simpler to install, and quieter than copper and iron pipes. Due to their inherent insulation, these thermoplastic pipes maintain the temperature of cold and hot water more effectively than copper pipes and reduce the likelihood of condensation on the pipes.
The lengths and end shapes of these pipes are the same. Due to their chemical make-up, which includes the halogen chlorine, they are naturally fire resistant. The long, practical performance lives of CPVC and PVC are due to these stable properties. For many years, PVC and CPVC plumbing supplies have been used by homeowners. PVC and CPVC are thought to be capable of lasting 50 years or longer under the right circumstances and with proper installation, according to historical data and independent research studies.
The color of the pipe can frequently be used to identify the material, or if it can’t, the manufacturer’s markings on the side can.
Most of the time, it is not possible to use PVC and CPVC interchangeably. Make sure to take into account both their capabilities and limitations when choosing between PVC or CPVC pipes. Hot-water applications, fire sprinkler systems, and water supplies are better suited to CPVC than PVC, which is best for cold-water applications and pressure or non-pressure systems.
Applications for PVC and CPVC pipes are covered in this section.
PVC Pipes
When deciding on the components for your construction projects, consider both the benefits and drawbacks of PVC pipes. PVC is frequently the more cost-effective and practical choice. Here are a few instances where PVC pipes can be useful:
Indoor Plumbing
PVC pipe is a fantastic choice for transporting drinking water because it has a high resistance to corrosive gases and chemicals. The water temperature won’t be impacted by outside temperatures thanks to its insulation qualities.
PVC is frequently useful for plumbing as well as drainage and cleanouts. When temperatures are constrained, CPVC is preferable.
Cold-Water Applications
One of PVC’s best applications is the transportation of cold water. Due to its superb insulation, water will remain cold and pristine.
Restrictions on Outdoor Applications
PVC is frequently used for underground applications such as drainage systems. PVC has a long lifespan when installed properly. It is not weatherproof, though. When used outdoors, it can be damaged by the sun’s rays and the cold.
Pressure Systems and Non-pressure Systems
The distribution of sea level changes within a pressure system. It’s important to check local requirements to make sure your PVC or CPVC complies. For both pressure systems and non-pressure systems, PVC is typically the best material. Among the many common uses of PVC in pressure systems are water supply lines, irrigation lines, drinking water lines, swimming pools, and fountains. Sanitary drainage, sewer lines, and roof drains are examples of non-pressure systems that can use PVC.
CPVC Pipes
PVC is frequently compatible with the use of CPVC. However, CPVC is only appropriate for specific applications due to the material differences. Here are some examples:
Hot-Water Applications
CPVC is a far better option than PVC for applications involving hot water because it can withstand temperatures of up to 200 F.
Applications Pertaining to Water Supply
Because of their chemical makeup and affordability, PVC and CPVC are unquestionably the best materials for water transport. Drainage is another common application for CPVC, in addition to carrying drinking water.
Although CPVC is technically equivalent to PVC, it is primarily used in homes for indoor water distribution systems (the pipes that carry water to fixtures). CPVC is the ideal material if the soil or water around your house is corrosive.
Fire Sprinkler Systems
While it might appear that CPVC would melt in a fire, it actually has the best fire protection rating. The substance has no flame-retardant properties and doesn’t emit smoke or burning droplets. Because of this, CPVC makes an excellent material for fire sprinkler systems.
Not Suitable for Freezing Conditions
The maximum and minimum water temperatures can both be handled by PVC and CPVC. Despite the fact that both kinds of pipes keep water cold, freezing temperatures can harm them. As a result, CPVC piping cannot be installed in a location where it might be exposed to temperatures below 32°F.
Conclusion
Similar to PVC, CPVC is not advised for pressurized gases or air but is acceptable for pressurized liquids up to certain limits. Both CPVC and its installation and use outdoors are not advised for the long term unless they have been painted or have a cover. It is only advised to use UV-inhibited CPVC for brief exposure to sunlight, such as during construction and installation activities.