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.