PVC Schedule 40 Vs. Schedule 80: Which Is Better?

Kenneth Wilson

A PVC pipe is offered in two different schedules: Schedule 40 and Schedule 80. When working with PVC pipes, you must know attributes like exterior diameter, wall thickness, and internal diameter. With that said, what are the main distinctions that will assist you in determining which choice is best for your project?

PVC in schedules 40 and 80 is used worldwide. Each has its set of advantages in different situations. Due to its thinner walls, the Schedule 40 pipe is best suited for conditions with low water pressure. Schedule 80 pipes have thicker walls and are capable of handling higher PSI pressures.

Pipe scheduling may be a difficult chore if you don't know what you're doing. Although scheduling is an essential aspect of pumping, most individuals struggle because they have no idea what the schedule refers to. (Related: PVC vs. CPVC: Finding The Right Pipe For Your Plumbing) Now, let's examine what a schedule is and the differences between PVC schedule 40 and schedule 80.

PVC Schedule 40 vs. Schedule 80


By now, you are aware that when working with PVC pipes, the term "Schedule" has no connection with time or dates. This standard of measuring pipes came from the need to have a universal system for references to measuring pipe thickness.

Since different wall thicknesses are beneficial in different situations, the ASTM (American Society for Testing and Materials) developed the Schedule 40 and the Schedule 80 system for classifying the two common types.

The term 'schedule' is the standard of wall thickness that has been adopted by the ANSI (American Notation Standards Institute).

Pipes are frequently identified by their nominal pipe size and schedule number because pipe schedules are frequently mentioned in construction and plumbing.  Knowing how the system works and the differences between Schedule 40 and Schedule 80, the two most common types of pipe schedules, is essential.

The nominal pipe size is a rough estimate of a pipe's outer diameter. It is a reference number, not a precise measurement; you may use that to establish the exact measurements of a pipe's outer diameter. For example, pipes with a nominal diameter of 3 have an actual outer diameter of 3.500 inches, for instance.

PVC Schedule 40 vs. 80: Features


Schedule 40 pipes have thinner walls than 80 pipes, even though they may be the same pipe size. The extra thickness of the schedule 80 pipe (on the right) can be seen in the above picture.

Schedule 40 PVC Features


  • Thinner Walls
  • The majority of these units come in white but always check the label.
  • Compared to wall thickness and structure, schedule 40 is the weaker unit overall than schedule 80 pipe.
  • Schedule 40 is best suited for applications involving lower water pressure.
  • As a result of being thinner than schedule 80, it has a larger diameter for fluid to flow.
  • The Schedule 40 units weigh less than the Schedule 80 units and thus are easier to install.
  • The Schedule 40 pipe is best suited for residential plumbing, drainage, irrigation, and other cold-water systems.
  • Schedule 40 is generally always cheaper than schedule 80.

Schedule 80 PVC Features


  • Thicker Walls
  • The majority of these units come in grey but always check the label.
  • It is a more robust and more resistant pipe.
  • It handles higher pressures.
  • It has greater structure and chemical durability.
  • It has a greater rigidity.
  • Can handle higher levels of strain and pressure.
  • Schedule 80 is best suited for applications involving high water pressures.
  • As a result of being thicker than schedule 40, it has a smaller inside area, which has more of a restriction in fluid flow.
  • The schedule 80 units weigh more than the schedule 40 and are more challenging to install.
  • The schedule 80 pipe is most often used in commercial, chemical, industrial, and manufacturing purposes because it is stronger and more resistant than its counterpart.
  • Schedule 80 pipes are likely to cost more than schedule 80 pipes.

The installation technique and characteristics are the same for Schedule 40 or 80 pipes produced of the same material. Outside diameters will be identical throughout schedules of pipes with equivalent NPS, according to ASTM specifications.

This facility allows pipes of various types to be connected using the standard fitting procedure for that piping material. Plumbing's maximum pounds per square inch (PSI) pressure rating is governed by how it is scheduled. For better pressure handling, pipes and fittings with higher schedule numbers will be permitted.

The increased material thickness indicated by the pipe schedule is a direct outcome of their service tolerance for higher fluid pressure. In general, Schedule 80 is a safer and more durable option for pressurized liquid applications.

However, if application pressure ranges are recognized to be within the piping's specified parameters, Schedule 40 may be a good fit. Schedule 40 and 80 PVC pipes are the most popular. However, schedule 120 PVC pipe is also available. Schedule 40 has a thinner wall than this pipe.

Other materials are also subjected to these schedules. For example, schedule 40 and 80 CPVC pipes and fittings are available. To distinguish this material from PVC, most producers employ various hues, such as light gray. Schedule is also used to define metal piping, such as steel, in addition to plastic pipes.

Which PVC Schedule Should You Use?


So, if you're looking to build a high-pressure or industrial pipeline, schedule 80 PVC can be a decent option. If not, schedule 40 PVC will suffice for many pressurized and non-pressurized applications. Schedule 40 PVC is also reasonably priced, ideal for non-plumbing projects such as a PVC pool chair or a scientific project.

Don't forget that your fittings are available in both schedules! All tees, elbows, and couplings are available in both schedule 40 and schedule 80.

Both schedule 80 and schedule 40 PVC pipes have the same outer diameter, as previously stated. Because the increased wall thickness of schedule 80 is on the pipe's interior, this is conceivable.

It implies that, although having the same pipe diameter as an identical schedule 40 pipes, schedule 80 pipe will have a somewhat reduced flow. It implies that schedule 40 and schedule 80 pipes can be used together if necessary.

Even one schedule 40 items put in a higher pressure schedule 80 line might cause catastrophic damage since your pipeline is only as strong as its weakest portion or junction. The only thing to remember is that the lower pressure handling schedule 40 components must fulfill your application's pressure requirements.

Conclusion


Before starting your own project at home, make sure you know what you'll be using the pipe for now that you are aware that both have their own set of advantages and disadvantages. And keep in mind that if you try and join the two, the whole system's weak point will be schedule 40's connection.

Their intended purpose, on the other hand, is plainly different. Therefore it's critical to examine the application and all relevant factors to determine which is best.

Kenneth Wilson
November 23, 2021
Plumbing

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done.

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