Ultraviolet light is a form of electromagnetic radiation and is responsible for the discoloration in PVC pipes. The radiation comes from the sun and transmitted in particles or waves. This occurs in different wavelengths and frequencies. The broad range of wavelengths is referred to as the electromagnetic spectrum.
The spectrum is divided into seven regions, depending on wavelength, energy, and frequency. The UV light has enough energy to break chemical bonds. UV photons have high energy. As a result, it can cause ionization, where electrons break away from atoms. In this article, you will learn more about PVC pipe sun damage.
The Effects of Sunlight Exposure
Is CPVC & PVC Pipe UV Resistant?
The two types of pipes are made of durable and versatile materials. This makes it hard to believe that they are not completely resistant to UV rays. CPVC is manufactured by treating PVC pipes with chlorinated water. CPVC can withstand high temperatures, and this makes them ideal for engineering and industrial piping projects.
Ultraviolet light radiation affects PVC and CPVC. When exposed to UV light radiation, the outer shell of the pipes degrades slightly. However, this does not cause significant damages. Over time, exposed pipes slowly begin to have a visible variation called “UV discoloration.” For example, they may turn brownish or yellowish, depending on the pipes’ color.
PVC and CPVC pipes experience degradation, but only between 0.001 to 0.003 inches. When removed from direct exposure, UV rays no longer affect the pipes. Increased sunlight exposure can decrease their impact strength and resistance. However, UV light does not affect the rigidity, pressure, and malleability of the pipes.
Additionally, some PVC fittings and pipes are impact-proof and resistant to UV radiation. Therefore, their colors remain unchanged under the sun. The effect of UV radiation is only noticeable after extended periods of exposure to sunlight.
The radiation penetrates PVC and CPVC pipes to a shallow depth. But experts still recommend protecting the pipes. Some pipes are manufactured by mixing thermoplastic materials with UV light blocking agents.
What Happens to PVC in the Sun?
The effect of sunlight exposure on PVC pipes is a common question. The sun emits visible and non-visible radiation. Ultraviolet light is a form of non-visible radiation. Like many other substances, the pipes are affected by UV light. The light affects molecules in the pipes and results in discoloration.
This does not happen where a pipe is not exposed to sunlight. Usually, the discoloration stops when PVC pipes are kept away from direct sunlight. The process is time-dependent and can be slowed by using UV absorbers. The most common additive used to achieve this objective is known as titanium dioxide.
According to some studies, the only feature of PVC pipes that is adversely affected due to sunlight exposure is impact resistance, which is the ability to withstand violent contact. Continued exposure to sunlight will not affect the pressure capacity of a PVC pipe or its stiffness.
Some of the factors that affect the extent to which impact strength is affected when exposed to sunlight include the time of exposure, the climate, a pipe’s width, wall thickness, and PVC materials used. If the pipe’s wall is thick, the impact becomes less noticeable.
Pipes with thin walls should be handled with care to avoid breakage. After installation, there will be no effect on a pipe’s pressure or external load capacity. If you intend to install PVC pipes above the ground, ensure they are protected from UV radiation. This can be done in several ways.
Which Type of PVC Is for Exposed Outdoor Use?
All types of PVC pipes are subject to degradation when exposed to direct sunlight. Without proper protection, your pipes will have reduced impact resistance. Some of the pipes are UV resistant. Although such PVC pipes may degrade, this occurs at a slower rate.
It will take more time for thicker walls to fail, as the upper layers will catch the UV before penetrating the lower layers. If pipes are to be installed outdoors, they should be painted. The paint to be applied should reflect UV light. Most paints can be used for this purpose.
Mostly, PVC pipes are designed to be used underground, where they are protected against UV light. However, they eventually come out of the ground. If the exposed portions are unprotected, they become vulnerable to failure.
How Long Does a PVC pipe Last for?
PVC pipes are some of the commonly used materials in plumbing work due to their durability. According to research, they can last for about 100 years. However, their lifespan will also depend on substances they are exposed to and how they are installed.
Although experts believe PVC pipes can last for a century, the exact lifespan is unknown as they have not been around that long. There are numerous factors that can result in weakening or damage the pipes.
One of the things that can shorten the lifespan of your PVC pipes is exposure to sunlight. If a PVC pipe is run above ground and becomes exposed to sunlight, it will break faster than it normally would. UV radiation can break down the structure of PVC pipes and make it breakable.
How to Protect PVC from the Sun?
Ultraviolet rays cause damages to PVC pipes. There are several ways of protecting the PVC pipe from the sun. For example, you can paint them using ultraviolet-resistant paint. Experts recommend people to apply a thin coat of a light-colored latex-based paint on all exposed portions. By doing so, you will prevent discoloration and make them last longer.
When it comes to shopping for PVC pipes, purchase from dealers with a covered warehouse to ensure they are not exposed to UV radiation. Some chemicals used for PVC pipe sun protection can be dangerous. For example, wear your gloves when using PVC primer. Before you apply it, clean your pipes with water.
Clear away stickers and debris that may be present. You can use a naphtha-based fluid to remove oil and adhesive through them. Next, rinse any chemicals used for the cleaning exercise using warm water. Use a dry cloth to dry them. The primer is only effective if the pipe is dry.
Once the pipes are dry, cover them with PVC primer. Use paintbrushes to get rid of the excess primer. Paint the pipes using a paintbrush to ensure you apply an even coat. Light colors are ideal for this purpose.
Finally, like many other surfaces, when PVC pipes are exposed to direct sunlight for extended periods, they can degrade due to UV radiation. The good news is, you can protect them against sun damage by applying paint.