Pipes and Tubes may look similar, they are in fact quite different in nomenclature and sizing. Remember that pipes and tubes are rarely interchangeable.The difference between pipe and tube include:ShapeMeasurementTelescoping AbilitiesRigidityApplicationsMetal TypesSizeStrengthShapePipes are always round in shape. Tubes can be square, rectangular or round, as shown in the image to the right.MeasurementPipes 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 a