Is CPVC & PVC Pipe UV Resistant?
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Time to read 3 min
CPVC and PVC pipes are made out of very strong and versatile materials. It is hard to believe that they are not completely resistant to UV rays.
Chlorinated Polyvinyl Chloride (CPVC) is made when Polyvinyl Chloride (PVC) is treated with chlorinated water. They are available for engineering and industrial piping projects because CPVC can withstand a greater array of high temperatures. It is able to endure a majority of acidic and corrosive substances. CPVC are used on extremely hot and cold water systems and chemical applications. These pipes are cost effective, easy to install, and resilient.
PVC is a thermoplastic material that is extremely versatile. It is used for a variety of applications. The PVC pipes come in a range of sizes and dimensions. They are strong and rigid, used for gas, water, and drainage systems. PVC is not recommended for hot water systems over 140 degrees. It has been found that the pipe walls begin to soften when in contact with substances that are higher than 150 degrees. Alternatively, CPVC pipe is more flexible and durable for hot water industrial projects where temperatures can reach a maximum of 200 degrees.
Although they are similar, CPVC and PVC pipes are not interchangeable for commercial, residential, and industrial assignments.
The Effects of Ultraviolet Light Radiation
Ultraviolet (UV) light is an invisible form of radiation that is emitted from the sun. It can be used as a treatment for people with vitamin D deficiency diseases, such as rickets, osteomalacia, cystic fibrosis, and short bowel syndrome. Although it is a great source of vitamin D, too much UV radiation can cause skin cancer, premature aging, eye damage, and immune system diseases.
CPVC, PVC Pipes, and Ultraviolet Radiation
UV light radiation can cause portions of the outer shell of CPVC and PVC pipes to degrade slightly, but not significantly. Pipes that are exposed to sunlight will slowly begin to have a visible variation, called “UV Discoloration”. Depending on the pipes’ color, it can start to have a brownish or yellowish tint. When exposed to direct sunlight, CPVC and PVC shows “UV degradation”, but only between 0.001 to 0.003 inches. Once pipes are removed from the direct exposure, the ultraviolet rays no longer affect them.
Long-term sunlight exposure can decrease the CPVC and PVC’s impact strength and resistance. Ultraviolet light does not seem to have a bearing on the rigidity, pressure, or malleability of the pipes. In addition, Furniture Grade PVC fittings and pipes are non-toxic, impact proof, and resistant to UV radiation. They will not change color under the sun.
Extra Protection against UV Radiation
CPVC and PVC pipes are affected by UV radiation after extended periods of exposure to sunlight. The radiation penetrates the pipes down to a shallow depth; it is still advisable to protect the pipes. Some pipe manufacturers mix the thermoplastic materials with ultraviolet blocking agents. These pipes can withstand longer exposures out in direct sunlight. Another way to protect pipes from UV exposure it to conceal them with an opaque covering or paint them with acrylic-based latex paint. UV radiation cannot penetrate the surface of latex paint.
Minor Surface Degradation: Standard PVC and CPVC are not fully UV resistant; prolonged sunlight causes discoloration and shallow surface degradation (0.001–0.003 inches).
Impact Loss vs. Structure: Exposure reduces the pipes' impact strength, but it does not affect their pressure rating, rigidity, or pipe-wall functionality.
Protection Solutions: Outdoor pipes can be protected using water-based acrylic latex paint, opaque coverings, built-in UV-blocking additives, or UV-resistant Furniture Grade PVC.
FAQs
Are standard PVC and CPVC pipes fully UV resistant?
No, neither standard PVC nor CPVC is entirely immune to UV radiation. Prolonged exposure to direct sunlight causes shallow surface degradation (0.001 to 0.003 inches) and discoloration, which can reduce the pipe's overall impact resistance over time. However, sun exposure does not affect the pipe’s pressure capacity or rigidity.
Does UV light damage Furniture Grade PVC the same way as standard PVC?
No. Unlike standard plumbing-grade PVC and CPVC, Furniture Grade PVC is specially formulated with built-in UV inhibitors. This makes it resistant to UV radiation, preventing it from yellowing, becoming brittle, or degrading when used outdoors.
How can you protect exposed PVC or CPVC pipes from sunlight?
You can protect outdoor pipes by covering them with an opaque barrier or painting them with an acrylic-based latex paint. Latex paint creates a protective shield that blocks UV rays from penetrating the surface of the pipe.
Mark Ligon
Mark Ligon is the marketing manager at PVC Fittings Online, a supplier of commercial PVC and CPVC pipe, fittings and valves. Ligon enjoys educating businesses on the parts of piping systems so managers can make informed decisions. He can be reached at webmaster@commercial-industrial-supply.com.
