At Eagle Stainless, we know that while the terms tube and pipe are sometimes used interchangeably, there are essential distinctions in their ordering, applications, and tolerances. Understanding these differences ensures you select the right product for your specific needs, whether working on a precision application or transporting fluids in an industrial setting.
Function and Applications
The main difference between tube and pipe is their use. Tubes are used in structural applications with critical dimensions, such as medical devices, aerospace, and precision instruments. For example, medical tools require small-diameter tubing for safe, accurate fluid delivery, while aerospace relies on tubing that withstands extreme conditions.
On the other hand, pipes are designed to transport gases and liquids. Their internal capacity and pressure-handling ability are key. Pipes are essential for plumbing, gas lines, and industrial fluid systems, ensuring efficient and reliable flow. Their circular shape evenly distributes pressure, making them ideal for handling liquids or gases under pressure.
Classification and Measurement
Pipes and tubes are measured using different sizing systems. Nominal pipe size classifies pipes (NPS), which indicates their approximate size, and a schedule number that defines wall thickness. However, depending on the size, wall thickness can vary between pipes with the same schedule number.
Tubes, on the other hand, are ordered by the exact outside diameter (OD) and wall thickness to ensure precise sizing for engineering and manufacturing applications. Combinations like OD & ID or ID & wall thickness can also specify them. Tube wall thickness may use a gauge number, with smaller numbers indicating thicker walls. Unlike pipes, tubes come in various shapes, such as round, square, and rectangular, offering more versatility for structural uses.
Shapes and Structural Differences
One of the primary differences between tube and pipe is their overall shape and intended function. Pipes are always round, ensuring even pressure distribution for high-pressure fluid and gas applications. Conversely, tubes are available in multiple shapes—round, square, or rectangular profiles—making them ideal for structural applications and precision assemblies and engineered components. For example, square or rectangular tubing are often used in construction frameworks, medical devices and precision instrumentation where dimensional stability, strength or specific designs are needed.
Tolerances and Specifications
Tubes and pipes differ significantly in their tolerance requirements and manufacturing precision. Tubes are made to tighter tolerances, which is essential for industries where small deviations can affect performance, safety or functional accuracy. For example, surgical instruments or precision gauges require exact tube dimensions to ensure reliable operation and consistent, repeatable results..
Pipes are produced with looser tolerances, focusing on flow capacity rather than precision. This makes them ideal for plumbing or industrial fluid transport applications, where exact dimensions are less critical.
Ordering Guidelines
When ordering tubing, specify two dimensions: outside diameter (OD) and wall thickness. You might also choose OD and inside diameter (ID) or ID and wall thickness. Since tubing has three dimensions (OD, ID, and wall thickness), only two include tolerances, while the third is theoretical.
Pipes are ordered differently, using Nominal Pipe Size (NPS) and schedule number. the NPS value gives a standard size, while the schedule number defines wall thickness. This system makes pipe selction and ordering straighforward – especially in large-scalre plumbing, industrial piping and fuid transport-systems where consistent sizing and flow requirements are critical.
Need Help Selecting the Right Product?
Understanding the difference between tube and pipecan be challenging, but our team at Eagle Stainless is here to help. Contact us to discuss your project requirements and find the perfect solution. We’re committed to delivering quality products and exceptional service to meet your needs.