Schedule 40 vs Schedule 80 Pipes and Fittings
Looking to understand pipe scheduling and how it applies to choosing the right plumbing for your application or usage scenario? Want to know what is meant by Schedule 40 and Schedule 80? Many modern pipes and fittings, especially plastics like PVC and CPVC, use the scheduling method to categorize and define plumbing thicknesses based on size. But what is the difference between Schedule 40 and Schedule 80, the most common types? And what are the important points concerning pipe scheduling and how is it used? Together we will explore these considerations in what schedule means for pipes and fittings.
What is Meant by Pipe Scheduling: Sch. 40 & Sch. 80
First, pipe scheduling has nothing to do with the human concepts of time or schedules, rather, it is a defined measurement pattern. Scheduling is a fabrication plan used to specify a plumbing material's required total wall thickness depending on the full size of the pipe in terms of its width not its length. In other words, pipe scheduling is a set standard for how thick a pipe's wall must be based on how wide / large the pipe is in diameter.
You can think of pipe schedule as a data table that has been pre-filled with textbook standardized values for pipes and fittings. Manufacturers seeking to produce 2" Schedule 40 PVC pipe will know exactly how thick (at minimum) the pipe walls must be to be classified as a 2"; Schedule 40 PVC pipe. The exact wall thickness value requirements will differ on the specific pipe schedule intended and the plumbing's desired total width diameter.
By definition, as pipe schedule values increase, e.g. Sch. 40 versus Sch. 80, the pipe wall thickness also increases. This in turn indicates Schedule 80 pipe will always have thicker sidewalls when compared to Schedule 40 pipe, when used for a specified pipe size diameter and material. Between pipe schedules, the plumbing's wall thickness is the main variable / parameter that changes and corresponds to a change in the pipe's Inner Diameter (ID). The Nominal Pipe Size (NPS) and Outer Diameter (OD) measures for a given pipe are not affected by different pipe schedules -- e.g. a 6" NPS with a 6.625" OD will measure this way for either Sch. 40 or Sch. 80. The increased wall thickness between schedules occurs as a reduction in the Inner Diameter measurement.
How is Pipe Scheduling Used
Pipe scheduling is used by contractors, construction and engineering firms as well as general plumbing handlers, installers and DIY (do it yourself) builders. Pipe schedules are used to understand the suitability of the pipe and/or fittings for their intended application(s). Whenever evaluating and comparing plumbing components and materials, professionals will choose the pipe size and schedule rating that has been designed and determined to meet and/or exceed the intended work demands. In simpler words, pipe scheduling is used to determine the plumbing equipment that is right for the job. In plumbing scenarios, it is important to compare and understand required pipe thickness, pressure ratings, chemical suitability and total costs, all of which are factors associated with and differ between pipe scheduling ratings.
Comparing Schedule 40 and Schedule 80
- Thickness -- Pipe wall thickness is the main physical difference between Sch 40 and Sch 80. The material thickness of pipes and fittings will be greater with higher number schedule ratings. Schedule 40 will have thinner walls than Schedule 80 for the specified pipe size. This means less material, which may mean a weaker product, which in turn can affect its project suitability if the integrity of the plumbing may be in question for the intended use. Thicker pipes, i.e. higher schedule pipes, will have greater structural and chemical durability, rigidity, and resilience to strain and pressure.
- Pressure -- The maximum pounds per square inch (PSI) pressure rating for plumbing can be determined by its scheduling. Pipes and fittings with higher schedule numbers will be acceptable for greater pressure handling. Their service tolerance for increased fluid pressure is a direct result of the increased material thickness that is indicated by the pipe schedule. For pressurized liquid applications, Schedule 80 makes for a safer, more durable choice in general. However, Schedule 40 can be well suited if application pressure ranges are understood to be within the piping's determined parameters. See our table below that outlines the dimensions and working pressures for both Schedule 40 and Schedule 80 PVC piping.
- NPS and Outer, Inner Diameter -- The Nominal Pipe Size (NPS) measurements for both Sch 40 and 80 piping will be the same for the same pipe size. NPS is similar to the pipe Outer Diameter (OD) measurement, which will also be the same for both schedule types. The Inner Diameter (ID) measurement is what differs between Sch 40 and Sch 80. In Sch 80, the additional material used increases the sidewall thickness on the inside of the plumbing only. This reduced inner diameter of Sch 80 accounts for a slight restriction in fluid flow through the pipe.
- Cost -- Plumbing rated as Schedule 80 normally has a higher purchase cost over plumbing parts manufactured according to Schedule 40. The extra material that accounts for Sch 80's thicker sidewall, as well as the included colorant (if applicable) contribute to its increased cost.
- Color -- Schedule 40 and 80 pipes often have a different color that is used to distinctly identify them. Sch 40 plumbing is traditionally natural white that lacks any color additives, while Sch 80 plumbing is traditionally a colored grey. Note that outliers to the norm often exist and specific manufacturers may not follow this common color pattern. While color can often indicate and contrast Sch 40 and 80 piping, always verify by reviewing the detailed info printed along the sides of pipes and fittings.
- Installation -- Installation does not differ between Schedule 40 / 80 piping that has been made of the same material. According to ASTM standards, outside diameters will be equal across schedules of pipe that have equal NPS. This specification allows for pipes of different scheduling to be coupled together using the normal fittings and joining method for that piping material.
- Corresponding Application & Use -- Due to the greater wall thickness of Schedule 80 plumbing, it is collectively understood to be stronger and more resistant than its Sch 40 counterpart. Plumbing applications that encounter increased pressure stress, mechanical strains, and/or chemical interactions often benefit from the use of a greater pipe schedule for the parts.
This is not to say Sch 80 is the best option simply because an application will transit liquids / water under pressure or handle chemicals. Rather, plumbing applications are extremely specific, especially those involving chemicals, and what is the best choice -- Schedule 40 or Schedule 80 -- will be an educated decision that considers the full variables of the pipe's intended use. If Sch 40 is acceptably rated for the operational conditions of the scenario, one can save both piping material and associated costs by choosing to use Schedule 40 over Schedule 80 plumbing.
Property Table for Schedule 40 and Schedule 80 Plumbing: PVC & CPVC
The following property table overviews and compares Schedule 40 and Schedule 80 for its thickness, size, and maximum working pressure for fluids. Consider this chart and pressure ratings for pipe sizes whenever wanting to determine the compatibility of the pipe schedule for an application.
Schedule 40 & 80 PVC, CPVC Size & Operational Pressure Table
| Nominal Pipe Size (NPS) | Outside Diameter (OD) | Schedule 40 Wall Thickness | Maximum Pressure (PSI) | Schedule 80 Wall Thickness | Maximum Pressure (PSI) |
| 1/8" | 0.405 | 0.068 | 810 | 0.095 | 1230 |
| 1/4 | 0.540 | 0.088 | 780 | 0.119 | 1130 |
| 3/8 | 0.675 | 0.091 | 620 | 0.126 | 920 |
| 1/2 | 0.840 | 0.109 | 600 | 0.147 | 850 |
| 3/4 | 1.050 | 0.113 | 480 | 0.154 | 690 |
| 1 | 1.315 | 0.133 | 450 | 0.179 | 630 |
| 1 1/4 | 1.660 | 0.140 | 370 | 0.191 | 520 |
| 1 1/2 | 1.900 | 0.145 | 330 | 0.200 | 470 |
| 2 | 2.375 | 0.154 | 280 | 0.218 | 400 |
| 2 1/2 | 2.875 | 0.203 | 300 | 0.276 | 420 |
| 3 | 3.500 | 0.216 | 260 | 0.300 | 370 |
| 3 1/2 | 4.000 | 0.226 | 240 | 0.318 | 350 |
| 4 | 4.500 | 0.237 | 220 | 0.337 | 320 |
| 5 | 5.563 | 0.258 | 190 | 0.375 | 290 |
| 6 | 6.625 | 0.280 | 180 | 0.432 | 280 |
| 8 | 8.625 | 0.322 | 160 | 0.500 | 250 |
| 10 | 10.750 | 0.365 | 140 | 0.593 | 230 |
| 12 | 12.750 | 0.406 | 130 | 0.687 | 230 |
| 14 | 14.000 | 0.437 | 130 | 0.750 | 220 |
| 16 | 16.000 | 0.500 | 130 | 0.843 | 220 |
| 18 | 18.000 | 0.562 | 130 | 0.937 | 220 |
| 20 | 20.000 | 0.593 | 120 | 1.031 | 220 |
| 24 | 24.000 | 0.687 | 120 | 1.218 | 210 |
Schedule 40 vs Schedule 80 Takeaways
If seeking to understand pipe scheduling, especially for PVC and CPVC, our article above hopefully shed some light on the definition, key differences, and usage considerations for both Schedule 40 and Schedule 80. If not, maybe read it again. Otherwise, feel free to reach out to us with any and all questions, comments or needs.
If looking for Schedule 40 or Schedule 80 PVC or CPVC pipe, we offer it here at the industry's most competitive pricing options and from only the industry's top manufacturers. Because here at PVC Pipe Supplies, we are hard-plumbed that way: to provide only the best of the best and with product guarantees and warranties to support it. Reach out to our professionals and expert teams today for your plumbing solutions.
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FAQs
Do Schedule 40 and 80 use the same fittings? ›
Because schedule 40 PVC and schedule 80 PVC pipe have the same outer diameter, you can use schedule 40 PVC fittings with schedule 80 PVC pipe and vice versa.
What is the difference between SCH 40 and SCH 80 fittings? ›Schedule 80 pipes have a thick wall and are used for high pressure operations in a commercial and industrial setting. Schedule 40 pipes have thinner walls and are intended mostly for residential settings.
What are Schedule 80 fittings? ›PVC Schedule 80 Pipe is for pressure applications and has a thicker wall than Schedule 40 pipe. It is highly durable, easy to install and has better sound deadening qualities than PVC and ABS Foam Core pipes. Installation requires the use of primer and solvent cement.
What is Sch 40 used for? ›Schedule 40 steel pipe is the most commonly used pipe schedule. It can be galvanized — although it doesn't have to be — and is usually used in water and gas lines. It may also appear in places that need ornamentation or support. It makes a great pipe due to its versatility and performance strength.
Can I use SCH 80 fittings with SCH 40 pipe? ›Sizing & Diameter
This means schedule 80 pipe will have a slightly more restricted flow – even though it may be the same pipe diameter as an equivalent schedule 40 pipe. This means schedule 40 and 80 pipe do fit together and can be used together if necessary.
What is schedule 80 PVC used for? Because schedule 80 PVC is a thicker pipe, it is usually is used for applications that are commercial or industrial in nature. These more demanding applications generally require piping that will stand up to high pressures and harsh environments.
Is Schedule 40 or 80 stronger? ›Schedule 80 pipe is designed with a thicker wall. This means the pipe is thicker and stronger, and as a result it can handle higher pressures. You are probably most familiar with schedule 40 PVC pipe.
Does Schedule 80 pipe have a seam? ›It is manufactured without a seam and requires very little maintenance.
Is Schedule 80 pipe seamless? ›Thick walls, also known as Schedule 80, give this pipe the strength to handle high-pressure applications. It is seamless so it has a smooth interior for unrestricted flow.
Why use black pipe? ›Black steel piping is mainly used to carry gas into commercial buildings. This pipe is seamless, and this makes it perfect for carrying gas. Also, this pipe is more fireproof than carbon steel piping. Therefore it is also used in fire sprinkler systems.
How do I choose a pipe schedule? ›
- Measure the outside diameter and the wall thickness of the pipe.
- Refer to the pipe schedule chart and find the outside diameter.
- Find the wall thickness in the corresponding column.
- This will reveal the nominal pipe size and the schedule.
Polyethylene Pipe
Polyethylene pipes are used in a wide range of pipes for drainage, irrigation, water service and even some varieties for underground gas transport. It is durable and provides long-term resistance to environmental conditions in outdoor and underground uses.
Most schedule 40 PVC found in homes and offices is white pipe with a National Sanitation Foundation (NSF) rating for potable water.
Can Schedule 40 PVC be used for electrical conduit? ›Schedule 40 PVC Pipe
Schedule 40 PVC Conduit electrical pipe is used for electrical wiring in walls, floors and ceilings in accordance with NEC 352. According to NEC 352 it can also be buried directly into the earth, encased in concrete, and used in areas exposed to direct sunlight.
It is manufactured without a seam and requires very little maintenance. Carbon steel pipe can be cut and threaded to fit your needs.
Can you thread a sch 80 pipe? ›Threading is the process of joining one pipe end to another, particularly with the use of a schedule 80 or 120 material.
Can you thread a sch 40 pipe? ›It is because of this taper or conical shape, that Schedule 40 and thin wall pipe cannot be threaded or used for nipples. Threads are cut deeper at the end of the pipe causing a wall thickness reduction.
What is the difference between GREY and white PVC? ›PVC pipe that is used for plumbing is usually white while electrical conduit PVC is usually gray. These are the standard colors, but you can find PVC that has had chemical additives added during the manufacturing process to create different colored pipes.
Do trade size 1 schedule 40 and schedule 80 PVC use the same fittings? ›Trade size 1 Schedule 40 and Schedule 80 PVC use the same fittings (coupling and connectors). Notes: PVC "connectors" are properly identified as male or female adapters.
Are all PVC fittings Schedule 80? ›PVC is most commonly found in schedule 40 and 80, but schedule 120 PVC pipe exists also. This is an even thinner wall pipe than schedule 40. These schedules are applied to other materials, too. For instance you can buy schedule 40 and 80 CPVC pipe and fittings.
Are PVC fittings Schedule 40? ›
Schedule 40 PVC Fittings, also known as polyvinyl chloride, are used in a wide range of commercial (business) and consumer (residential) applications. From DIY projects & home irrigation to in-ground pool installation and water transport.