Although pipes and tubes may look similar, they are actually quite different in nomenclature and sizing. Remember that pipes and tubes are rarely interchangeable.

The difference between pipe and tube include:

Shape

Measurement

Telescoping Abilities

Rigidity

Applications

Metal Types

Size

Strength

Shape

Pipes are always round in shape. Tubes can be square, rectangular or round, as shown in the image to the right.

Measurement

Pipes are only provided with an inside (nominal) diameter and a “schedule” (which means wall thickness). There’s an easy way to remember this: since pipe is used to transfer fluids or gas, the size of the opening through which the fluids or gas can pass through is probably more important to you than the outer dimensions of the pipe. Tube measurements, on the other hand, are provided as an outside diameter and set ranges of wall thickness.

Telescoping Abilities

Tube can be telescoped. Remember to account for the flash weld inside the tube. Pipe, on the other hand, does not have a flash weld. DOM (Drawn over Mandrel) Tube is the best material for telescoping because the inside flash weld has been removed.

Rigidity

Although copper and brass tubes can be shaped relatively easily, tubes are typically rigid. Pipes, on the other hand, are invariably rigid and cannot be shaped without special equipment.

Applications

Only pipes are pressure rated and intended to be used for the transference of fluids or gas. Tubes, on the other hand, are used in structural applications.

Metal Types

Tube is available in hot rolled steel and cold rolled steel. Pipe is typically black steel (hot rolled). Both items can be galvanized.

Size

Pipe is typically available in larger sizes than tube.

Strength

Tube is stronger than pipe.