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Chlorinated Polyvinyl Chloride (CPVC) Water Supply Piping

Alternative rigid polymer pipe

Chlorinated polyvinyl chloride (CPVC) is a rigid, thermoplastic pipe and fitting material approved for potable water distribution throughout the United States. CPVC pipe is joined to CPVC fittings with solvent cement and requires only inexpensive, readily available, and easy-to-use tools.

CPVC has been used successfully in residential, commercial, and industrial applications for over 50 years. Its most common application is in single-family and multifamily hot and cold water distribution systems. CPVC can also be used for residential fire sprinkler systems, gray water systems, reclaimed water, chemical drain waste systems, industrial processing, and commercial and high-rise construction. The key advantages of CPVC are its low cost, resistance to corrosion, pitting, and scaling, its ease of installation, and its light weight

Though PVC and CPVC both belong to the thermoplastics family and possess similar base materials, they perform very differently. The chlorination process used in making CPVC gives the material superior performance in high temperature and high pressure applications. The extra chlorine content makes CPVC very difficult to burn. CPVC will not sustain a flame on its own in normal conditions and extinguishes once the flame source is removed. Additionally, CPVC piping does not react unfavorably to elements in various water systems that may affect other piping materials..


Affordability

CPVC piping may be a more affordable alternative to copper piping systems, reducing the overall cost for the homeowner.

Energy Efficiency

There is less heat loss from CPVC than from metallic pipe, making for a more energy efficient supply water system.

Quality and Durability

CPVC is recommended for use in places with more aggressive soil and/or water conditions (e.g. coastal areas) because it will not pit or corrode regardless of the pH level in the water.

Quieter operation is one of the primary benefits realized with CPVC pipe and fittings. Since CPVC is more flexible than metallic pipe, the exterior wall of the pipe can expand slightly and absorb water flow noise, resulting in a significantly quieter operation.


Easy

The transition from copper to CPVC should be a simple one. The material is light-weight, readily available, and joints are easily made with solvent cement; no special tools or skills are required. For remodeling and repair, connector components are available to link CPVC to existing systems of other materials.

CCPVC piping for plumbing systems is manufactured by extrusion in sizes 1/2-inch through 2-inch in copper tube size (CTS) dimensions. CPVC is also available in iron pipe sizes (IPS) and as fire sprinkler pipe. Standard pressure ratings of CPVC pipe in SDR 11 CTS dimensions are 400 psi at 73°F and 100 psi at 180°F.

CPVC piping is sold in straight lengths as well as in coils for small diameters. Fittings, elbows, couplings, hangers, and adapters are inexpensive and readily available. The material is easy to move, store, cut, and install. Care should be taken during handling in cold temperatures and during shipping to ensure that the piping is protected from impact to avoid damage. Quality CPVC manufacturers have improved product to reduce these issues.

CPVC can withstand the ultraviolet exposure commonly experienced during the construction phase of a project. If CPVC is used in above-ground, outdoor applications, protection from ultraviolet attack can be achieved by shielding or by painting the system with an exterior-grade latex paint.


The labor savings afforded by a CPVC system will vary depending on the size and complexity of the project. Some contractors have documented as much as a 50 percent labor savings as a result of switching from copper to CPVC. This savings is attributed to the fact that CPVC is joined using a fast and easy solvent cement process which replaces the more time-consuming task of soldering. CPVC is also lighter in weight than copper (approximately one-sixth of the weight) so contractors will save time and effort trying to maneuver material on the jobsite.


A CPVC plumbing system should cost the same to operate as any other piping material in the same layout (e.g. trunk and branch). However, a CPVC system can save money on repairs if a leak occurs or reconfiguration is needed. CPVC piping is easy to work with and does not require specialized tools, soldering, or welding. CPVC is energy efficient, since less heat is lost as hot water moves through the pipes, as compared to copper.


Although local plumbing codes may vary with regard to installation and testing requirements, CPVC is approved for hot and cold potable water use in all 50 states.


None available


CPVC piping is connected using a fast and easy solvent cement joining process for joints, thus eliminating the use of torches and solder. Installers can use a fine-tooth saw to cut CPVC and a chamfering tool or pocket knife to remove any burrs or filings prior to joining. Circular tubing cutters with a plastic cutting blade and ratchet cutters are also acceptable. Cutting blades should be kept sharp to help ensure a square cut. Care must be taken in colder temperatures when using a ratchet cutter, as the cutting force could cause pipe walls to crack. CPVC supply water systems typically follow a trunk and branch layout. After installation, the pipes are secured to the studs or supports with metal hangers that allow proper movement due to thermal expansion. CPVC should be secured every three feet horizontally according to the IPC.

Pressure testing can be done once the solvent cement has reached the recommended cure time. The cure time is based on product and ambient temperature, but in some installations, pressure testing can be done in as little as 10 minutes after the last joint has cured.

CPVC joints can be used in underslab applications. This is the predominant plumbing method in some states, such as Florida. Due to the solvent cement joining process, the joint of a CPVC plumbing system becomes the strongest part of the system when properly installed and is more durable than either the pipe or fitting alone. Newer technologies have allowed for bendable, CPVC composite pipe to be manufactured, which is convenient for underslab applications without joints.

When connecting CPVC to a gas water heater, use at least six inches, or the code required length, of metal pipe or appliance connector so that the CPVC tubing is protected from excessive heat from the draft diverter. Some high-efficiency direct-vent gas water heaters eliminate the radiant heat from the flue and can be piped directly to the water heater. CPVC can be piped directly to an electric water heater and can be used with residential tankless heaters. A brass-threaded CPVC transition fitting is recommended for these applications. Note that some code jurisdictions require metal connections on all water heaters. Verify code requirements prior to installation.

CPVC can be used as the water heater discharge lines as well. It is approved for this application by all major plumbing codes, including the Standard Plumbing Code.


Some manufacturers offer warranties dependant on proper installation of CPVC piping, ranging from 6 months to the duration of the original owner’s ownership of the property.


CPVC provides a rigid piping system that is preferred by many builders and plumbers. CPVC will not corrode, pit, scale, or pinhole leak like copper regardless of less than favorable local water or soil conditions. The piping is also quieter and more energy efficient than copper. CPVC can be used in stand-alone or multipurpose fire sprinkler systems. And, CPVC pipe is less expensive than copper piping. Its cost, ease of workability, and durability make it an economical choice.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.