Pipe and Pipe Sizing
The tubing used in hydronic heating systems is made of copper, steel, plastic, or rubber. The size of the pipes or tubing used in these systems depends on the following two factors: (1) the flow rate of
The water and (2) the friction loss in the tubing. The flow rate of the water is measured in gallons per minute (gpm), and constant friction loss is expressed in thousandths of an inch for each foot of pipe length. For a description of the various types of tubing used in hydronic heating systems see the appropriate sections of Chapter 8, “Pipes, Pipe Fittings, and Piping Details” in Volume 2, which also describes the sizing methods used.