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Differences Between Schedule 40 and Schedule 80 Pipe
- Authors
- Name
- William Smithson
Pipe selection is an important decision. Especially when it is between Schedule 40 and Schedule 80 pipes. Everything is different about both types. Let it be names, structures, or applications. The differences are evident.
This blog helps you make the right selection between the two pipes. Let's learn more about steel pipes and their uses.
What Does Nominal Pipe Size Mean?
The measurement of a pipe consists of three main categories which are:
- Nominal Pipe Size (NPS)
- Internal Diameter (ID)
- Outside Diameter
NPS or Nominal Pipe Size is a measuring standard. It measures the exterior diameter of a pipe. The measurement of a pipe relies more on the internal diameter (ID). The Nominal Pipe Size is thus considered a vague pipe measurement.
Nominal Pipe size belongs to the North American set of standards. The use of NPS is to identify a pipe by name only. Nominal means the name of the pipe. This is applicable in the dictionary of pipes.
Outside and inside diameters mean the exact measurements of the pipe. These measurements are both from inside and outside.
NPS is a very relevant term. This is the case when considering schedule 40 pipes.NPS categorizes and differentiates schedule 40 pipes. Each type of pipe has its own specific NPS value. For Schedule 40 pipes, the NPS value ranges from ⅛ to 36 inches.
Schedule 80 pipes have different wall thicknesses than Schedule 40 pipes. Yet, the NPS value in Schedule 80 pipes remains consistent. They have the same NPS value as Schedule 40 pipes, i.e. ⅛ to 36 inches.
What is Schedule 40 Pipe?
The "schedule 40" in the schedule 40 pipe indicates the tensile pressure. It shows that the Schedule 40 pipe can tolerate 40 kilograms of pressure. But these pipes can have different diameters. Take the example of 2 Schedule 40 pipes. It has a Nominal Pipe Size of 2 inches. Its external diameter is 2.375, and its internal diameter is 2.067.
Schedule 40 pipe is the most common type for gas and water lines. They also serve decorative and support purposes.
Versatile use and performance strength are two main advantages of schedule 40 pipe. The composition of most steel pipes is mild steel. Mild steel means the carbon content range is between 0.2-0.25 percent. Low carbon content makes the pipes more ferrous. Ferrous means a more excellent iron content in the product.
To increase the resistance of these pipes to corrosion, manufacturers galvanize them. Galvanization is the process of adding an extra zinc layer.
The "schedule 40" in the schedule 40 pipe indicates the tensile pressure. It shows that the Schedule 40 pipe can tolerate 40 kilograms of pressure. But these pipes can have different diameters. Take the example of 2 Schedule 40 pipes. It has a nominal pipe size of 2 inches. Its external diameter is 2.375, and its internal diameter is 2.067.
Schedule 40 pipe is the most common type for gas and water lines. They also serve decorative and support purposes.
Versatile use and performance strength are two main advantages of schedule 40 pipe. The composition of most steel pipes is mild steel. Mild steel means the carbon content range is between 0.2-0.25 percent. Low carbon content makes the pipes more ferrous. Ferrous means a more excellent iron content in the product.
To increase the resistance of these pipes to corrosion, manufacturers galvanize them. Galvanization is the process of adding an extra zinc layer.
What is Schedule 80 Pipe?
Although they have the word schedule, it has nothing to do with time. In Schedule 80, the pipe dimensions schedule is nothing but terminology. Schedule means how thick the pipe's walls are. A greater schedule means that the pipe has thicker walls. Thicker walls state that the pipe is strong enough to tolerate high pressure.
80 refers to the pressure or tensile strength of the Schedule 80 pipe.
Schedule 80 pipes have thick walls. They have industrial and commercial uses. Schedule 80 pipes can withstand high pressure.
Schedule 80 pipe is usually available in dark grey. However, adding other colors during the manufacturing process is also possible. The purpose of adding colors is to differentiate it from other pipes. Although not very common, the schedule 80 pipe is also available in two more colors. These are white and black.
Schedule 80 pipes can show resistance to up to 140 degrees F. A temperature beyond this limit can cause damage to the pipe.
How do you Manufacture Schedule 40 and Schedule 80 Pipe?
The manufacturing process of all steel pipes consists of four steps, i.e.
###. Choosing raw materials
The first step is choosing the raw steel. Choose high-grade carbon or stainless steel. Raw material arrives in the form of coils or flat sheets.
###. Shape formation of pipes
This part involves the circular shaping of the pipes. You can use any of two methods:
- Seamless Pipe Production and
- Electric Resistance Welded Method (ERWM)
Both methods are good at creating consistent and precise circular pipes.
###. Maintaining the size of the wall thickness
The manufacturing process of schedule 40 and schedule 80 pipes is almost similar. The similarity persists until the second step. The third step makes them different. This is because both pipes differ in wall thickness. Controlling the steel gauge is important in this step.
###. Quality control
The last step involves a variety of steps. The purpose of quality control is to make sure that the pipe is of high quality. They also make sure that the pipe gives the greatest performance. Some of these tests are:
- Hardness test
- Flattening test
- Ultrasonic test
- Hydraulic test
What is a Pipe Schedule?
The thickness of steel pipe walls is measured in terms of pipe schedule. The pipe schedule exists in numerical form. Yet, the number does not describe the thickness. It indicates a set of standardized thicknesses.
A formula determines the value of this set of standard thicknesses. The value of a pipe schedule refers to the pipe's nominal size. It also explains the pressure rating.
An increase in the value of the pipe schedule refers to an increase in the wall's thickness. It also indicates that the pipe is capable of tolerating high pressure.
Different types of pipes have different standards of pipe schedule. The pipe schedule standards for a carbon pipe might differ from those for a stainless steel pipe.
Before, there were only three pipe schedules for steel pipes. These were strong, extra strong, and double extra strong. But, they were not sufficient. Hence, 14 pipe schedules currently measure the thickness of pipe walls.
Schedule 40 vs. Schedule 80 Pipes- Comparison and Differences?
| Schedule 40 Pipe | Schedule 80 Pipe | |
|---|---|---|
| Weight | Considering the weight schedule, 40 pipes are less heavy. | When comparing to schedule 40 pipe schedule 80 pipe is heavier. |
| Pressure Resistance | Schedule 40 pipe pressure rating ranges from 130 PSI to 450 PSI. This is not greater than the scheduled 80 pipes. It is because of the thickness of schedule 40 pipe walls. | Schedule 80 pipes offer high resistance to pressure. This is because of thick pipe walls. Schedule 80 pressure rating ranges between 220 PSI to 850 PSI. |
| Thickness of walls | Schedule 40 vs 80 steel pipe thickness is a point to ponder. This is the main differentiating factor between the two. The walls of Schedule 40 pipes are thin. | In the case of schedule 80, the thickness of the wall is greater than that of schedule 40 pipes. It means that the walls of schedule 80 pipes are thicker. Schedule 80 pipes are thirty percent thicker than schedule 40 pipes. |
| Durability | Schedule 40 pipes are less durable than Schedule 80 pipes. These are more applicable for general-purpose applications. They might not be able to bear high pressure. Also, they are not very resistant to high temperatures. | High resistance to pressure and thick walls makes these pipes more durable. |
| Cost-effectiveness | Schedule 40 pipes are more cost-effective and less pricey. Since they have thin walls, they need less manufacturing material. This reduces their manufacturing cost. | Schedule 80 price is more expensive. This is because it requires more material for composition. Of course, thicker walls of the pipe need more material. This makes it less cost-effective. |
| Applications | These pipes are part of low-pressure applications. Residential plumbing and irrigation systems use these pipes. | Industrial and commercial applications use schedule 80 pipes. These include hydraulic systems and underground piping. |
| Color | Schedule 40 pipes are usually available in white color. | Schedule 80 pipes are available in dark grey color. |
Schedule 40 Vs 80: Which Is Stronger?
Until now, the difference between schedule 40 and 80 pipe is very clear. Now comes the very important question:
Which is stronger?
Schedule 80 pipes. They are more resilient than schedule 40 pipes. Not only are they stronger, but also more durable.
Strength is the main reason manufacturers prefer to schedule 80 pipes, especially in industrial applications. In addition, there are other features:
- Schedule 80 pipe has thicker walls.
- The pressure rating value of schedule 80 pipes is more excellent. Especially in comparison to schedule 40 pipes.
- Schedule 80 pipes can withstand more temperature changes.
Conclusion
Both schedule 40 and schedule 80 pipes have their structural differences. They have different applications and uses as well.
Schedule 40 pipes serve residential uses. Schedule 80 pipes serve industrial purposes. The most important feature that differentiates the two is wall thickness. If you are building a house and want a gas or water supply pipe, use schedule 40 pipes. The best choice between the two depends upon the purpose.