Category: Pipe

Pipe vs Tube

Metal pipes and metal tubes are both cylindrical structures made of metal, but they have some key differences in terms of their design, purpose, and typical applications.

Purpose & Function

  • Metal Pipe: Pipes are primarily designed to transport fluids, gases, or solids from one location to another. They are used for conveying substances like water, oil, gas, and various chemicals. Pipes often have specific standards and regulations depending on their intended use.
  • Metal Tube: Tubes, on the other hand, are more versatile and can serve various purposes beyond the transportation of materials. They are often used for structural applications, heat exchangers, mechanical components, and as a framework for various structures.

Wall Thicknesses

  • Metal Pipe: Pipes typically have a uniform wall thickness. The wall thickness is designed to withstand the specific pressure and temperature requirements of the substance being transported. Pipe walls are often thicker than those of tubes.
  • Metal Tube: Tubes can have varying wall thicknesses, making them suitable for a wide range of applications. Some tubes have thicker walls for structural strength, while others have thinner walls for heat exchange purposes

Shapes & Cross-Sections

  • Metal Pipe: Pipes are generally designed with a round cross-section, which is ideal for maintaining consistent flow and reducing resistance in fluid transportation.
  • Metal Tube: Tubes can have various cross-sectional shapes, including round, square, rectangular, and oval, depending on the intended application.

Manufacturing Standards

  • Metal Pipe: Pipes are often manufactured to specific industry standards, such as ASTM (American Society for Testing and Materials) or ASME (American Society of Mechanical Engineers) standards. These standards ensure that pipes meet the required quality and safety criteria.
  • Metal Tube: Tubes can also be manufactured to industry standards, but they are often more flexible in terms of size and shape, making them suitable for a wider range of custom applications.

Applications

  • Metal Pipe: Common applications for metal pipes include plumbing systems, oil and gas pipelines, and industrial processes where the conveyance of fluids and gases is essential.
  • Metal Tube: Metal tubes find applications in industries like construction, automotive manufacturing, aerospace, and engineering, where structural strength, heat transfer, or specialized shapes are required.

In summary, the key difference between metal pipes and metal tubes lies in their primary purpose and design. Pipes are mainly used for transporting materials, while tubes serve various structural and mechanical functions in addition to material conveyance. The choice between a pipe and a tube depends on the specific requirements of the application.

What are Pipe Schedules?

For people new to working with pipe, referring to their “schedule” may be unfamiliar. Imagine you have two pipes in front of you: one labeled schedule 40, while the other is schedule 80. Both are manufactured of the same type of metal, with the same grade, and the same 3-inch diameter. So, what is it that makes these two pipes different, other than their schedule numbers?

First, it helps to understand the functional challenges faced by pipe. Pipe is designed to move along liquid or gas under pressure – pressure which can be internal, external, or both. To sustain fluid pressure, pipe must be strong enough to withstand a great deal of stress. This means the product dimensions of pipes aren’t simply measured by length and diameter, but its wall strength as well. A high-pressure fluid will require thicker pipe walls than pipes used for low-pressure applications like drainage.

Pipe Schedules
The wall thickness that determines a pipe’s strength is known as its schedule. Pipe schedules are a standard to identify wall thickness for the same size of pipe. The outer diameter of a particular pipe size will stay constant while the inner diameter varies according to the schedule type. Using the example of the 3-inch pipes, you can see the difference once you measure their inner diameter. The outer diameter for both pipes will remain approximately 3.5 inches, but their other qualities differ:

3” Schedule 40 pipe
• Wall thickness of 0.216 inches
• Inner diameter of 3.05 inches
• Weight per foot is 7.58 pounds

3” Schedule 80 pipe
• Wall thickness of 0.300 inches
• Inner diameter of 2.90 inches
• Weight per foot is 10.25 pounds

As you can tell, the schedule 80 pipe is significantly heavier due to its thicker walls. Those thicker walls mean schedule 80 pipe is better able to handle high pressure, which might cause greater wear or damage to schedule 40 pipe. Clearly, pipe schedules are quite important to ensure a project’s success and the best use of your funds. For home plumbing projects, schedule 40 pipe is sufficient, with no need to spend extra for schedule 80 pipe. For industrial uses, on the other hand, investing more money up-front for schedule 80 pipe may help prevent damage and costly repair work in the future.

What are the Differences between Tube and Pipe?

It’s not uncommon for someone to assume tube and pipe are interchangeable terms. You yourself may not have ever considered what the difference might be. If asked, what might be your guess: maybe they’re called pipes when made of metal, and tubes if made of PVC? Are they simply the same thing no matter what the name, the way different people might refer to soda versus pop?

Basically, it comes down to use: tube is a structural element, while pipe is used to transport fluid or gas. While both types are lengthy hollow cylinders, their use means they are different in their measurements, desired qualities, and even shapes.


10 Differences Between Tube and Pipe


1. Size Measurements


Pipe is more approximate in its measurements, with sizes being referred to as nominal pipe size (NPS). The pipe’s inner diameter and wall thickness are the most important dimensions, and vary according to strength. A very strong pipe will have thick walls with a smaller inner diameter than an equivalent NPS with thinner walls.
When measuring tube, its outer diameter and wall thickness are also important dimensions. Unlike pipe, these will be the exact measurements of the tube’s cross section.

2. Wall Thickness


Pipe wall thickness is known as its schedule, and determines the liquid capacity of a pipe. Two pipes with the same NPS number but different schedule numbers will have a difference in inner wall thickness.
Tube wall thickness is defined by gauge, with the wall’s width increasing along with a higher gauge number.

3. Production Sizes


Pipe comes in a wide variety of lengths, often 6 feet or more. Tubes, on the other hand, are most often smaller parts. Many are 5 inches or less, although larger tubes can be used for some applications.

4. Materials


Many different materials can be used for pipe: iron, copper, brass, and PVC. Tube is most often made of some type of steel, whether that’s carbon, low-alloy, or stainless steel.

5. Shapes


A pipe will always be round. Tube can be made in round, square, and other shapes.

6. End Connections


The ends of pipes can be straight, beveled, or screwed. Tube ends are commonly threaded or grooved for quicker connections.

7. Tolerances


An item’s tolerance is the acceptable range in its measurements: any deviations in its straightness, shape, or strength. Pipe tends to have a wider tolerance, so long as it meets its designated schedule requirements. Tube is the opposite, being made with strict tolerance guidelines. Because tube is intended for structural and often mechanical use, strength is a high priority. Repeated quality checks are made on a tube’s straightness, gauge, and outer surface.

8. Production Process

Pipe manufacturing is quite efficient and speedy, with many items being made to stock. Production of tube is more exacting due to its strict tolerances and quality checks, which means a lengthier, more labor-intensive process.

9. Delivery

Due to the difference in production, availability also varies between pipe and tube. Pipe, especially if ordered in made to stock sizes, is likely to have a quick delivery. Tube generally takes longer to produce and ship

10. Price

As you may have already guessed, the time and effort used to produce tube also translates to a higher price tag. While pipe can be pricey, especially if made of metals like copper, the average price of pipe will be lower than tube.