Is PVC UV-Resistant Enough for Outdoor Use?

PVC window in the sun

Polyvinyl chloride (PVC) is a long-lasting and durable thermoplastic formed from chlorine, carbon, and ethylene. Many industries utilize this plastic material in part because it’s inexpensive and readily available, but not only.

Another feature of polyvinyl chloride that makes it popular among various industries is its outstanding tensile strength. Indeed, PVC is known to be very resistant to water, as well as inorganic chemicals and alkalis. This material is also impact-resistant, meaning that it can withstand intense force over a short time.

Although some PVC materials are UV-resistant, not all of them are. The non-UV-resistant polyvinyl chloride materials, when exposed to sunlight, tend to change color from their natural white color to brown. However, PVC materials, such as furniture-grade PVC, do well when exposed to UV rays.

PVC is one of the world’s most versatile plastics thanks to its compatibility with many different kinds of additives. In this post, we’ll look at everything regarding PVC and ultraviolet (UV) protection, and will also discuss how to make PVC UV-resistant.

Is PVC UV-Resistant?

When choosing a plastic to use outdoors, you should consider environmental factors, such as UV radiation, an invisible form of light emitted by the sun. Indeed, UV rays have a way of degrading some plastic materials, such as pipes, thus limiting their life span.

Only a few plastic materials, including polycarbonates, acrylics, high-density polyethylene (HDPE), polyetherimide, and polyphenylene sulfide, are UV-resistant. The rest, including polyvinyl chloride, can easily get affected by ultraviolet radiation.

As mentioned earlier, UV light radiation can cause the outer layer of PVC materials to degrade. While that’s true, the effects are not significant. For instance, if a PVC material gets exposed to sunlight, the UV rays cause it to lose its natural white color due to a process called UV discoloration.

The UV degradation process follows different stages. It starts with the loss of gloss and then moves to the next step: chalking. The final stage is where the degradation occurs. When PVC and chlorinated polyvinyl chloride (CPVC) pipes get exposed to UV rays, the color usually changes from white to yellow, brown, and then black. However, the color change is time-dependent and often occurs over a long period.

As stated earlier, when exposed to direct sunlight, polyvinyl chloride degrades but only slightly — between 0.001 to 0.003 inches. That said, you can rest assured that the material inside your PVC is safe from UV rays.

Is PVC Good for Outdoor Use?

Polyvinyl chloride materials aren’t the best when it comes to designing products for outdoor use. Instead of considering PVC and chlorinated polyvinyl chloride, you can use several different thermoplastics available out there.

For instance, acrylic is one of the best plastic materials to consider for outdoor products. The transparent thermoplastic homopolymer is UV-resistant, meaning that it cannot degrade when exposed to UV rays. That is unlikely of most PVC materials, which slightly lose their lifespan over time. Furthermore, the material is somehow rigid and brittle. With that, it means acrylics aren’t ideal for applications with common heavy impacts.

Apart from acrylics, you can make use of polycarbonate plastics. These materials also show excellent weather resistance and can withstand the effects of sunlight without degrading.

You can also utilize HDPE plastic for your outdoor products. This material is the most common for playground equipment as it is weather-resistant and doesn’t degrade when exposed to UV radiation for a long time. Marine board is another type of HDPE plastics that suits outdoor products. These materials can be used outside and even underwater.

But back to the burning question: is PVC good for the outdoors? The answer is no, polyvinyl chloride isn’t suitable for constructing outdoor products because it tends to degrade when exposed to ultraviolet radiation.

Many people prefer to use PVC materials for constructing their outdoor products because of a couple of reasons. First, they are inexpensive and highly accessible. Apart from that, the UV rays’ effect on the materials isn’t that significant compared to other products.

Protect your PVC

If you’re considering using PVC for your outdoor products as well, I advise you to find a way of protecting them from sunlight by coating them with opaque materials or painting the PVC using water-based paint designed for outdoor use.

Alternatively, you can consider using furniture-grade PVC fittings and pipes due to their features, including non-toxic, impact-proof, and UV resistance.

How Long Will PVC Last in the Sun?

PVC pipes came as an alternative to available plumbing materials during the 1960s.

Most PVC pipes are primarily designed for use underground as plumbing materials. They are durable, impact-resistant, and can last for many years. According to experts, the lifespan of polyvinyl chloride materials is about 100 years. However, there isn’t proof of that yet, as none of the pipes have been in service for that long.

As previously mentioned, one of the few factors that can reduce chlorinated polyvinyl chloride and polyvinyl chloride’s lifespan is ultraviolet rays. Indeed, after long-term exposure to UV radiation, PVC pipes tend to degrade, break easily, and even lose color. All of that will limit their lifespan. However, when covered with opaque materials, you can expect them to last for a long time.

How Do You Make PVC UV-Resistant?

Most PVC materials will degrade when exposed to ultraviolet radiation. However, if you’re interested in making use of them for outdoor products, there are a few ways you can go about making them UV-resistant. One of them is to coat the PVC pipes with opaque materials or other types of paints. Although, while doing that, ensure that the pigments or the opaque materials are UV-resistant.

Let’s have a quick look at the simple and straightforward steps to protect your PVC from the effects of UV rays.

  • Start by setting up your work area. For safety purposes, ensure that you work in a ventilated space as some chemicals tend to have adverse effects when used in an enclosed space.
  • The next step involves cleaning the PVC materials. But before doing that, make sure you wear protective materials, such as a face mask and hand gloves.
  • One way to clean the polyvinyl chloride materials is by using a clean rag. Also, you can use naphtha-based fluid to remove oil stains on the PVC pipes.
  • After cleaning the PVC materials, ensure you thoroughly dry them.
  • Next, cover the pipes with a primer and allow them to dry correctly.
  • Lastly, paint the pipe using ultraviolet-resistant, water-based paint.

What Type of PVC Is Ideal for Exposed Outdoor Use?

The ideal type of polyvinyl chloride for exposed outdoor use is the furniture-grade PVC pipe.

In case you didn’t know, furniture grade PVC, also called structural grade PVC or medical grade PVC, is a type of polyvinyl chloride that packs several different features. Some of them include strength, UV resistance, and weather resistance.

Speaking of the difference between furniture-grade PVC and standard PVC, both pipes of the same size have the same outside diameter. With that, it means a single fitting can work for both furniture-grade and standard PVC pipes.

In terms of aesthetics, furniture-grade PVC and standard PVC slightly differ as the former is shinier. Also, furniture-grade polyvinyl chloride is free from writing or bar codes, which is unlikely of standard PVC.

However, the most significant difference between standard plumbing PVC pipe and furniture-grade PVC is that the latter is UV-resistant and designed to be used for constructing outdoor products. Indeed, by using furniture-grade polyvinyl chloride pipe, you can rest assured that the end product won’t degrade nor lose color when exposed to UV rays. Apart from its UV-resistance, furniture-grade PVC also features high-impact resistance, tempered edge, impact-proof, and better connection.

Benefits of PVC

There are many benefits attached to using PVC materials. One of them is that polyvinyl chloride is cost-effective, unlike some other types of plastics. Plus, it comes with great features and at competitive prices.

Furthermore, the materials are non-toxic and completely safe for people to use. Also, PVC materials are versatile. For instance, in the building and construction industry, PVC materials help create siding and windows, wiring and cables, and water pipes.

Finally, the durability feature of PVC materials makes them useful in the packaging industry. Moreover, PVCs are also helpful in the healthcare sector, where they are used for creating IV bags and medical tubing for dispensing medicines.

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