Cpvc Dwv Pipe

0 views

Skip to first unread message

Kay Hamling

unread,

Aug 3, 2024, 11:45:32 AM8/3/24

to seacolorus

This difference in makeup allows CPVC to withstand a wider range of temperatures. This is why many building codes require the use of CPVC as opposed to PVC for use in hot water applications. The ASTM standard allows PVC to be used in applications not exceeding 140 degrees F.

There are a few other differences between the two materials. Most North American PVC pipe uses a Nominal Pipe Size (NPS), while CPVC is available in either NPS standard sizing -OR- CTS (Copper Tube Size) sizing.

Before purchasing CPVC be aware of what your use will be, and what sizing system you require. Color can be a clue, too. Often CTS CPVC is a light yellowish color, while schedule 80 CPVC (NPS) is a light gray color.

As mentioned before, CPVC is more suitable for hot water applications up to 200F. PVC is still often used for unheated water as well as for vent and drainage systems; however, CPVC has become widely used for both hot and cold potable water.

The more resistant properties of CPVC make it useful for commercial and industrial applications as well. Because of its wider range of applications, CPVC is usually pricier than PVC. That being said, it is still a very cost-effective and versatile material.

We recommend the use of PVC for recreational use/building, cold water systems, vent systems, and drainage systems. CPVC is recommended for applications where the maximum temperature will exceed 140 degrees Fahrenheit, but stay under CPVC's max rating of 200 degrees Fahrenheit.

Another deciding factor in which material to use is the chemical makeup of media being handled in your application. Though PVC and CPVC both are resistant to many of the same chemicals, some are best handled by one or the other.

All NPS size pipe and fittings will fit together, but it is not recommended that you mix and match materials. Mixing materials can compromise the pipe line's temperature and pressure ratings. For that reason we always recommend any pressurized pipe system be constructed using matching piping material and schedules.

The main difference between CPVC and PVC is the range of temperatures each is capable of withstanding. CPVC can handle temperatures up to 200 Fahrenheit, while PVC peaks at 140 Fahrenheit. Above those temperatures, both CPVC and PVC will begin to soften, increasing the risk of joints and pipes failing, and therefore, failing of the plumbing system.

PVC comes in nominal pipe sizes only, while CPVC is available in both nominal pipe sizes and copper tube sizes. CPVC has greater flexibility than PVC, and requires support at three foot intervals to maintain its position.

The color of PVC pipe is traditionally white or dark gray, with a technical description of the pipe printed on the side. PVC is available in both rigid form (also known as uPVC: commonly used in construction and piping applications) and flexible form (plasticized PVC, known simply as PVC: found in electrical cable insulation). Both forms of PVC are safe to touch and handle, and do not leach chemicals when used as the manufacturer intended.

PVC can be cut with saws and glued to other PVC pipes and fittings without the need for heat or flame, such as is necessary to weld copper or iron pipes. For some applications you may determine a need to heat the pipe to make it more pliable -- be sure to wear protective gloves, respirator, and safety glasses to prevent burns and exposure to fumes. When PVC discolors under heat, it is burning and all work should cease immediately and be modified to prevent excessive toxins from becoming airborne.

PVC has a peak temperature threshold of 140 Fahrenheit. For applications requiring temperatures above that, CPVC (chlorinated polyvinyl chloride) is recommended. CPVC offers some benefits over PVC, but at a slightly higher price point.

CPVC is a thermoplastic made by further chlorination of the polyvinyl chloride resin. This means its chemical composition is two carbon atoms bonded to each other with two hydrogen atoms and two chlorine atoms bonded to this double carbon unit. This molecule links with others to form polymer chains of CPVC. CPVC delivers superior resistance to degradation and provides a long service lifespan. In fact, the first piping systems using CPVC occurred in 1959 and are still working without a problem.

CPVC pipes are sized in two ways -- nominal pipe size (NPS references the diameter of the interior hole of the pipe) and copper tube size (CTS references the outside diameter of the tube). Often, pipes using the NPS system are light gray, and pipes using CTS system are yellow. Both types of pipe will have their specifications printed on the side.

It is safe to use CPVC in applications where PVC may be used. Both PVC and CPVC have been deemed safe for potable water transport, i.e. cooking, drinking, and bathing water, but only plumbing that has received ANSI / NSF 61 certification should be used. CPVC and PVC both offer significant chemical resistance and are largely resistant to degradation from acid, alkali, and most inorganic chemicals. However, both materials require UV stabilizers or underground installation to prevent deterioration from the sun.

CPVC and PVC are both a quieter, easier to install, and less expensive alternative to copper and iron pipes, especially in plumbing applications. Because they are thermoplastics, they have an inherent insulation that reduces condensation formation on the pipes and maintains both cold and hot water temperature better than copper pipes do.

They are available in the same lengths, with the same end shape options. Because their chemical composition contains a halogen -- the element chlorine -- their structure is stable and innately fire retardant. This stability also inhibits oxidation reactions, resulting in giving both PVC and CPVC a long, useful performance life. Each material can often be identified by pipe color and, if not, by reading the manufacturer printing located on the side of the pipe.

Budget-friendly, temperatures under 140 Fahrenheit, most suitable for recreational applications, residential construction, DIY projects and cold water distribution. Looking for PVC pipe for sale or to compare prices?

Superior resistance and performance, temperatures under 200 Fahrenheit, most suitable for commercial applications, chemical handling and hot water distribution. Looking for CPVC pipe for sale or to compare prices?

PVC (polyvinyl chloride) that has been chlorinated via a free radical chlorination reaction. CPVC is produced by adding chlorine to PVC in a water slurry or fluidized bed chlorination process. The chlorination reaction is initiated by ultraviolet light. The chlorinated PVC is compounded with ingredients necessary for the desired properties for further processing. The chlorine added to PVC gives CPVC higher temperature performance and improved fire and corrosion resistance.

CPVC is a high-temperature plastic pressure piping system introduced for potable plumbing in 1959. It has also been used extensively in fire sprinkler systems since 1985. This material is also used for many industrial and process piping applications. CPVC pipe is available in nominal sizes from 1/2" to 24" and is approved in all model plumbing and mechanical codes across the United States and Canada. In addition, CPVC pipe and fittings from select manufacturers are listed for light hazard fire sprinkler systems, as defined in NFPA 13, 13R and 13D standards.

Aloha, Just picked up all my tools and realized I still have the brand new can of CPVC glue. Did about 20 fittings with PVC glue. It's my place
and the wife don't know yet. Carpenters shouldn't plumb. Should I get the saw ??? Thankx Kev from the Big Island.

The solvents used in the 2 glues are the same (ratios may differ slightly), so it might "appear" to work. However, each glue has the specific "bulk" material for its intended application, CPVC in the CPVC glue and PVC in the PVC glue. This means that your CPVC joints have a PVC boundary layer inside and they will probably fail when under stress. I would cut'em out and redo.

In this area, CPVC fittings are relatively inexpensive. I hate to do things twice, but cleaning up after broken pipes is much worse!

CPVC pipes are manufactured to hold a sustained pressure of 175 psi at 180 degF. In pressure relief situations, you get a sudden pressure surge over in seconds. In that situation CPVC will hold up to at least 900 psi. Therefore I believe that it is appropriate to use CPVC as a TPRV relief pipe. With that being said, I have run into situations where defectively manufactured CPVC pipes have ruptured (at an extrusion knitline) during use but these situations have occurred during sustained usage (pipe under constant stress over a long time period) and involved attack (slow) of the defective knitline by incompatible trace chemicals. I believe that it is highly unlikely that a CPVC pipe being used as a TPRV relief pipe will fail because the pipe is not under constant stress. If the TPRV should open, there is only a brief stress event.

It is important to note that most ratings for piping are based on sustained working conditions, and what the material can actually withstand is a different story. Inspectors should not raise unwarranted concerns based on their own interpretations of material specifications. There is often more than meets the eye.

Good point. I should clarify that I am not specifically stating the requirements of any one state or jurisdiction. I only questioned Mr. Priddy on the actual material performance of CPVC when used as a TPRV discharge. YMMV as far as what is and is not allowed for TPRV piping.

The pressure relief valve extension is plastic and has a couple of elbows leading it to a drain. I always advise the client that the pipe should be copper and should terminate about 6" inches from the floor. I explain that it was routed to a drain to...