Schedule 40 vs. 80


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When looking at the pipe installation, we have multiple options as consumers of the product. Specifically, at PVC pipes, the main options we have are Schedule 40 and Schedule 80. These pipes both have their differences and unique qualities, but it is important to distinguish them when buying them in the market. 

schedule 40 pvc pipe

What is the difference in Schedule 40 vs. 80?

The main difference between schedule 40 pipe and schedule 80 pipe is size and diameter.

However, there is much more to it than that, and I will dive into them in the article. 

Regardless of the reason that you need either a schedule 40 or 80, this article will summarize the differences between them and their special qualities. 

The Meaning of Pipe Schedules

Before purchasing a pipe, you need first to know what pipe schedules are. The schedule number on pipes relates to the thickness of it. As the number goes up, of course, the thickness of the pipe is much larger.

While the schedule can be the same on different sized pipes, thickness will be different. Regardless of length, the thickness will differ. 

Here are some examples. The first one we have is the Pipe size 1.000” Schedule 40, with a thickness of 0.133”. On the other hand, Pipe size 2.000” Schedule 40 has a thickness of 0.154”.

Pipe Size 1.000” Schedule 80 has a thickness of 0.179” and Pipe size 2.000” Schedule 8 has a thickness of 0.218”. 

Given what we know above, we can see that the schedule number increases the wall size and that the thickness changes with the NPS, or normal pipe size. 

The Meaning of Nominal Pipe Size

The NPS, as mentioned in the earlier section, means the approximate inside diameter of the pipe. If the schedule number on the pipe is altered it does effect the inside diameter.

Note, though, that it does not affect the outside diameter. In 1927, the American Standard replaced the Iron Pipe sizing to the NPS, or the normal pipe size. 

Schedule 40

Schedule 40 is a steel pipe that is the most common in the market. It is used in a wide range of construction materials, as well as buildings. Further, it is so versatile that it is also sued in gas and water lines.

The aspects of the pipe, like its diameter, strength, and reactivity, make it the standard in construction. 

First, we have the material. It is typically made from low-carbon or mild steel. Whether it be the low-carbon or mild steel, the content that it is made of has less than .2 percent carbon.

However, for certain ways of using it, especially when the material has to be resistant to corrosion, the pipe has to be galvanized. Another way to do this is to plate it with a layer of zinc to protect the steel.

Pipe assemble Schedule 40

Finally, for even more extreme usage, when zinc cannot be used, schedule 40 can use stainless steel material instead.

The second trait of the pipe is its measurements. The term schedule applies to the measurement of the steel pipe, as evidenced above. Specifically, it refers to the wall thickness, while its secondary name categorizes its diameter.

Since the schedule tries to standardize its overall strength, the wall thickness does vary on the pipe diameter.

Schedule 40 can have a thickness of 1.727mm with a diameter of only ⅛ inches. It can also get as thick as 9.525 mm for a pipe with a 24 in diameter. 

The third trait is the strength of schedule 40. Its hardness is measured to be at 16.1 on the Rockwell scale and has a yield a strength of 423 MPa and ultimate strength of 470 MPa. 

Schedule 80

The schedule 80 PVC pipe is utilized in industrial and higher pressure water flow. The PVC pipe can even handle up to 140 degrees F of temperature, one of its most unique traits.

Further, the pipe comes in either 10’ or 20’ sections and available in plain end or belled end. Ultimately, this means that there is no coupling needed when you install it. 

gray pvc pipe

The pipe also ranges in length, from ½” to 24”. The ease of installation you can get from this pipe, as well as its very versatile capabilities, are what make it very great.

Further, the pipe is designed to handle jobs with a lot of pressure. This is mainly due to its material, which also makes it chemically resistant to corrosiveness. It is also recommended to use a strong primer and cement when installing schedule 80. 

A standard medium set PVC glue is recommended when you are installing the PVC if it is under 12” in length. Give the glue a lot of time to rest so you can have connections done properly. 

The Difference in Both Pipes 

Now, given the information that has been presented above to you, you need to ultimately choose between the schedule 40 v 80. Knowing the type of thickness in the PVC will be critical when choosing between the two, 

The main difference between the two pipes is sizing and diameter. A schedule 80 has thicker wall size, despite it having a diameter smaller than the schedule 40. Essentially, you can think of schedule 80 as a more dense version of schedule 40. 

Due to the thinness of the wall that schedule 40 has, it is not recommended in an installation where the pressure of the water is too high. If the water pressure is too high, it is primarily a job for schedule 80.

It is more likely to perform better in high situations due to the thickness and density associated with it. This is the primary reason that schedule 80 is used in more industrial and chemical usage.

Another difference between the two is cost. Due to the added thickness and how that can be prived as versatile function, schedule 80, to no surprise, should cost more than schedule 40. 

Further, there is a difference in diameter. A schedule 80 offers a more restricted flow. Due to the extra thickness that it has, it provides a smaller room for the water or any other fluid to go through it. 

Finally, there is a difference in color. Although this may not initially seem like an important trait, it is. This way, with different colors, you can associate the pipes from another perspective without fully inspecting the pipe.

A schedule 80 should be gray, while schedule 40 pipe is typically white. However, if you want to be extra careful, you should just check the labeling. 

In Conclusion

Given all that, to know what PVC is best for you and then uses that you imagine, consider the traits each one has, as mentioned above. If you have high-pressure situations, use Schedule 80.

If your project is more so in the residential area, use Schedule 40. This way, you can spend less money and get more bang for your buck. Yet, even with this, always check the pressure requirements of your project. 

Some residential projects may even require Schedule 80 rather than the standard schedule 40. If you are not extra cautious and use the schedule 40 v 80 instead, you may experience severe damage.

Avoid this by making sure, before the start of the project, the pressure and depth requirements that it contains. If you do not do that, you would be risking not only the progress of your project but also its safety for you and the others around you. 

Tony

Hi there, my name is Tony. Having worked in the construction industry for over 30 years and being a weekend warrior on my own home I definitely have plenty of war stories to share. Have a topic or project you are interested in trying? Let me know and we will try to put together an article or video on it!

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