At times, it may be difficult to decide whether to use PEX or CPVC for your plumbing needs.
But remember as a plumber, you must choose the right flexible tubing or fittings. The reason this guide explores all fundamental aspects bout PEX vs CPVC materials.
Take a look:
Chemical Structure of PEX and CPVC
CPVC stands for Chlorinated Polyvinyl Chloride. Ideally, the CPVC is a PVC (polyvinyl chloride) that has been subjected to a radical chlorination reaction. Consequently, this improves the desirable properties of the material.
As you can see from the chemical compounds in Figure 1 above, CPVC is not the same as PVC.
PEX refers to cross-linked Polyethylene. It is an improved polyethylene to make various PEX piping systems with better performance.
In short, both PEX and CPVC, are improved materials with better features for enhanced performance in the plumbing industry.
Cost of PEX vs CPVC
As far as the prices of these two materials are concerned, the CPVC pipe price is slightly higher than the PEX piping systems. Whether you consider the overall cost in terms of buying the PEX piping systems, crimping, and expansion, it will still cost higher.
Comparing PEX to CPVC Chlorine Resistance
CPVC plumbing pipes and fittings are inherently resistant to chlorine. Remember, chlorine forms a major constituent of most water treatment systems. Therefore, using CPVC pipes in water piping systems is generally safe.
This is not the case when it comes to PEX piping systems. Over the years, research has proved beyond reasonable doubt that PEX material is not inherently resistant to chlorine.
In certain conditions, the PEX material will begin to degrade. For instance, the rating for PEX tubes is about 180°F at a pressure of 100 pounds per square inch. However, it cannot maintain such conditions in the presence of chlorine.
When subjected to chlorine under such conditions, the rated temperature reduces by up to 40°F.
Furthermore, subjecting both CPVC pipes and PEX pipes to how chlorinated water has devastating effects. That is, it will lead to complete PEX piping system replacement due to failures and leaks.
In short, in chlorine environments, CPVC is better than PEX pipes. Ideally, this is attributed to the more chlorine molecules in the CPVC structure.
Is PEX Safe for Drinking Water than CPVC
Before settling for either CPVC or PEX, you must be sure of the best water pipe materials in terms of water quality. Well, there are many ways to examine water quality flowing through plastic water pipes types of any configuration.
Take for example;
- Considering the bio formation process within the pipes – comparing PEX pipes and fitting to CPVC pipes and fitting, the latter exhibit a very low possibility of biofilm growth.
- Possibility of material leaching – Under certain conditions, leaching may occur in the PEX pipes and fitting. This is not the case for the CPVC pipes and fitting. The CPVC pipes are NSF 61 certified. Therefore it implies they meet the necessary safety standards for use in water systems.
- Material permeability – CPVC flexible tubing is not permeable. Actually, this is not the case for the PEX plumbing material which may cause contamination under certain conditions. The Virginia Tech Research actually that CPVC is safe and impermeable.
In short, CPVC pipes offer better safety in water systems than PEX pipes.
Comparing PEX to CPVC Installation Requirements
Plastic pipe installation requirements will significantly affect the total cost of your project. Even when you choose either CPVC or PEX there are fundamental aspects you must consider for successful installation.
Let’s summarize these in the table below:
|PEX Installation Requirements||CPVC Installation Requirements|
|· A flexible tubing|
· Best for installation in areas with very small spaces
· Perfectly installed in areas around corners
· Require a few installation fittings
|· Relatively rigid piping system|
· You need more pipe fittings for successful installation especially in tight spaces and corners
· Installation around corners and tight spaces requires more fittings
PEX Vs CPVC Lifespan
When examining CPVC vs PEX longevity, the two plastic piping materials are durable.
Looking at PEX pipes, they are durable and can withstand fluctuating temperature conditions. They don’t degrade easily. Besides, they will not bust hence the PEX plumbing pipes will serve you for many years.
At the same time, the CPVC can withstand very low temperatures and high resistant to corrosion. These pipes will serve you better than traditional pipes.
However, comparing CPVC and PEX, the latter is more durable.
UV Exposure on CPVC Pipe vs PEX
CPVC has better performance on exposure to UV than PEX pipes. Exposing PEX pipes to UV will cause a faster breakdown.
Although CPVC pipes are resistant to UV, high-temperature variations may compromise the overall performance.
Bending PEX Compared to Bending CPVC
Some of the main CPVC pipe problems is the rigidity during the installation process. The bending radius is greatly limited, unlike the PEX pipes which are easy to bend.
Theoretically, some of the most common bend radii are:
|CPVC Bending Radius||CPVC Pipe/Tube Diameter|
|18 inches||½ inches or ¾ inches|
|24 inches||1 inch|
Of course, the situation is very different from the PEX pipes and tubes that offer a very tight bending radius. On the other hand, forcing CPVC to a very tight bending radius may cause cracks, which can compromise the overall performance.
Both PEX and CPVC have their unique strengths and weaknesses. Although these materials are durable, at times they do fail. Take for example:
- PEX is susceptible to oxidation degradation. Additionally, it has antioxidant stabilizers that will make the pipe more brittle-resistant.
- Of course, PEX is suitable for both cold and hot water supply systems, is burst-resistant, and does not require glue and other installation mechanisms. Unfortunately, the key disadvantages of PEX are that the material is not recyclable, and possibility of water contamination.
- Other advantages of CPVC are non-toxicity, resistance to residue build-up, flame resistance, and more flexibility compared to the standard PC pipes.
- On the flip side, the key disadvantages of CPVC pipes possibility of splitting when subjected to freezing temperatures, and the material is not recyclable.
You can see both PEX and CPVC materials have unique advantages and disadvantages in the plastic piping industry. It depends on a combination of factors you consider important in your next plastic plumbing projects. Therefore, there are instances where PEX is better than CPVC and vice versa.
In case you have any questions, we are here to help – contact us now.