Most people are confused about the differences between a pipe and a tube. Besides the fact that both are cylindrical, they also contain a hollow space inside, making it difficult to differentiate between the two. However, despite their striking similarities, tubes and pipes are remarkably different in both form and function. Let us look at some of these differences.
The actual sizes of tubes and pipes are determined using different parameters. A tube is measured by its outside diameter. A pipe, on the other hand, is measured by its nominal diameter. The thickness of a wall is vital since a tube depends on it for strength. The main yardstick for measuring a pipe is its inside dimension (ID) or its capacity.
Pipes are used on a variety of large applications that feature sizes from a half-inch to several feet. On the other hand, the tubes are much smaller. It is possible, but rare, to find a 10-inch tube in use. Most other tubes are below this size threshold.
2. Wall Thickness
For thinner tubes, the wall thickness is usually indicated by a gauge. Thicker tubings are specified using an inch or millimetre fractions. However, the standard tube has a gauge of 20, which translates to a thickness of between 0.035 to 2 inches.
The thickness of a pipe’s wall is referred to as a pipe schedule thickness. The most popular pipe schedules are the SCH40, while SCH80 is the heavy-duty option. The light-duty SCH20 is also occasionally used.
While a pipe is generally round and rigid, a tube can be round or any other shape. It is not uncommon to come across square and rectangular tubes. Due to its rigidity, it is not easy to shape a pipe without using a special tool. They are seamless and feature pressure ratings as a protection against leaks since they carry gases and liquids.
Pipes have a loose tolerance than tubes. Since you can use pipes to transport or distribute liquids and gases, their ratings have to be specific and strictly adhere to the recommended requirements in terms of straightness, pressure, or roundness.
5. The Manufacturing Process
Tubes undergo stringent inspection, tests and an elaborate manufacturing process. They, therefore, take longer to manufacture and deliver. Returns from tubes are also much lower compared to that of pipes.
A pipe’s manufacturing process is less complicated and therefore lends itself to mass production.
It costs more to produce a tube than it does to produce a pipe. They are consequently more expensive than pipes. Pipes, on the other hand, have a less complicated production process, a factor that makes it easy to produce them in bulk. This has the consequent effect of lowering their costs due to the economies of scale.
Since pipes transport fluids and gases, their outer and inner diameter is the key determinant of their pressure rating. Tubes are mainly used in scaffolding and other applications that require exact outside diameters. The outside diameter is, therefore, the main determinant of a tube’s strength.
Pipes are manufactured using low alloy or carbon steel. Tubes are made of brass, copper, mild steel, aluminum, stainless steel, etc. The difference in the quality of steel has implications for cost and applications.
Connecting pipes is a labour-intensive activity that requires threading, welding, or flanges. It also requires the use of relevant tools to get the job done effectively. Joining tubes is less labour intensive since all you have to do is join them by brazing, flaring, or coupling them.
Besides the shapes and diameter sizes of tubes and pipes, the main difference between them is mainly in their application, the materials used to manufacture them, and their cost.