In the past, cast-iron was the material of choice for drainage pipes and industrial applications in the United States and pretty much the rest of the world. Plastic pipes are more preferred now for various reasons.
When choosing a plastic pipe, you will need to choose between PVC, uPVC and even CPVC. I have written a detailed guide comparing PVC and CPVC here.
Oh! And there is still ABS. If you want to check out the differences between PVC and ABS check out this post.
So, what is the difference between PVC and uPVC pipes? Is PVC the same as uPVC? Which pipe is better between PVC and uPVC?
The main difference between PVC and uPVC is that PVC is plasticized while UPVC is unplasticized. PVC contains plasticizers (BPA and phthalates) which make it soft and flexible while the lack of plasticizers makes uPVC rigid but smooth.
While PVC is legal in the Unites States, it is banned in Europe due to the BPA and phthalates and instead uPVC is the pipe of choice there. Other than being rigid and therefore strong, uPVC pipe is also safe for the environment and the pipes are so smooth as well.
So, what is the difference between PVC and uPVC pipes? Which pipes should you opt for?
The difference between PVC and uPVC pipes is that PVC pipes contain plasticizers while uPVC pipes are unplasticized. As such, PVC pipes are soft and flexible while uPVC pipes are rigid. uPVC pipes last longer than PVC pipes.
In summary, PVC is not the same as uPVC. PVC is soft and flexible while uPVC is rigid. This is because PVC is plasticized through addition of BPA and Phthalates while uPVC is unplasticized.
Which is Better, PVC or UPVC?
I must start by stating that PVC and uPVC pipes have a wide area of application apart from plumbing pipes. In this case however I will focus more on their choice as a material for plumbing pipes.
In the above section, I mentioned that uPVC pipes are unplasticized and therefore more rigid that PVC pipes. As a matter of fact, the “u” in uPVC denotes that the pipe is unplasticized.
The rigidity of PVC pipes make them more durable than PVC pipes since they are more resistant to physical impact and they also resist degradation compared to their PVC “cousins”.
Can we therefore conclude that uPVC pipes are better than PVC pipes? That wouldn’t be accurate. There is a reason PVC pipes are preferred more than uPVC pipes in the United States when installing/replacing drain lines.
The process of plasticizing PVC is done on purpose. Otherwise it would be easy to just leave it unplasticized which is cost-friendly and eco-friendly too.
PVC is plasticized to make it flexible. Flexibility is not something which was present in cast-iron drain pipes and the fact that PVC pipes can achieve it is a bonus.
Why do you need drain lines to be flexible? As you can imagine, drain lines don’t always follow a straight line. If you need to install them around a curve, the flexibility offered by PVC pipes makes it possible instead of having many 90-degree turns which increases the likelihood of clogs and also makes it harder to snake the lines.
When installed well and maintained properly, PVC drain pipes can last as long as uPVC pipes. You can see why these pipes are the number one choice for plumbers in the USA.
PVC pipes are however banned in many countries due to the BPA and phthalate plasticizers added.
Bisphenol A, which is BPA is a chemical that is not only added to PVC but is also present in water bottles and other containers that store food.
The reason PVC pipes are not used to transport water is because the BPA can potentially seep into the water. BPA is especially a concern for young kids as explained in this article.
The United States’ Food and Drug Administration has however said that BPA at low levels is safe. The BPA levels in PVC pipes are low and this is probably why the pipes are perfectly legal although I am not sure if the level requirements are strictly adhered to.
Despite it’s luck of plasticizers, uPVC pipes are not used to transport portable water just like PVC pipes. That is done by chlorinated polyvinyl chloride (CPVC) pipes. More on that later.
One advantage of uPVC pipes over PVC pipes when used as drain lines is that PVC pipes are way too smooth, which helps the wastewater flow out effortlessly. Due to how strong uPVC pipes are, they are more resistant to chemical degradation and can withstand a wide range of temperature and pressure.
Other Uses of PVC and UPVC
Outside plumbing, PVC and uPVC materials are also widely used in the construction industry. PVC is mainly used to manufacture electrical conduits (to insulate electric wires) while uPVC is used to manufacture window frames and sills.
The choice of uPVC in the construction of window frames is a very obvious one. Apart from being so strong, uPVC resists weather-corrosion and does not decompose.
Unlike PVC, uPVC will not warp (change shape) when exposed to sunlight and it will also maintain its original color despite the weather conditions. Windows and doors with uPVC frames are also more energy efficient compared to those with wooden or metal flames.
Another thing to like about uPVC is that it is a very versatile material that can also be manufactured in different colors. If you for instance want it to look like real wood, you can do exactly that.
PVC vs UPVC vs CPVC
Now that you have learnt the differences between PVC and uPVC, how do the two of them compare to CPVC?
CPVC (Chlorinated Polyvinyl Chloride) is basically a PVC homopolymer which has undergone a chlorination process to improve its chemical and physical properties.
The main difference between CPVC and PVC is the temperature each can withstand before softening. PVC can withstand temperatures of 140 degrees while CPVC can withstand temperatures of up to 200 degrees Fahrenheit.
What about CPVC and uPVC? How different are they?
The difference between CPVC and uPVC is that CPVC just like PVC is plasticized (contains BPA and Phthalates) while uPVC as we have seen is unplasticized. Due to the chlorination process, CPVC has a high temperature threshold compared to uPVC.
Although PVC pipes are more flexible than uPVC pipes, CPVC pipes are even more flexible. As a matter of fact, CPVC pipes needs to be supported at intervals of 3 feet due to the high flexibility.
One similarity between the 3 different types of pipes is that they are all of the same pipes. These pipes are available in schedules 40 and 80 which I discuss in more details in this post.
The main advantage of CPVC pipes compared to PVC and uPVC is that they are used in the transportation of portable water. The chlorination process makes CPVC pipes corrosion-resistant and the minerals in water will not damage it.
Its high temperature threshold also means it can be used to transport hot water as well. At maximum, most water heaters are set at 140 degrees while CPVC as we have seen can withstand up to 200 degrees Fahrenheit.
Unlike PVC pipes which are only available in nominal pipe size, CPVC pipes are available in both nominal pipe size and copper tube sizes. You can therefore easily add it to a copper piping systems.
And basically that is the differences between PVC, uPVC and even CPVC. I hope you enjoyed reading this guide.