2Copper TubingCopper tubing was developed in the 1920s to provide an alternative to iron piping in a variety of uses.
3Desirable Features of Copper Good pressure and temperature rating for typical hydronic applications.Good resistance to corrosion from water-based system fluids.Smooth inner walls that offer low flow resistance.
4Desirable Features of Copper Lighter than steel or iron piping of equivalent size.Can be joined by the well-known technique of soft soldering.
5Copper Pipe SizeCopper pipe is available in a wide range of sizes and wall thicknesses.The type of tubing used in hydronic heating is known as water tube.
6ASTM B88In the United States, copper water tube is manufactured according to strict standards.This standard is known as ASTM B88.ASTM stands for American Society for Testing and Materials
7ASTM B88According to ASTMB88, the copper water pipe size refers to the nominal inside diameter of the pipe.The word “nominal” means that the measured inside diameter is approximately equal to the stated pipe size.
8Copper Tube SizingThe outside diameter (O.D.) of copper water tubing is always 1/8” inch larger than the nominal inside diameter (I.D.).For example, the O.D. of ¾” inch type M copper tubing is .875 inchesThis is exactly 7/8” inches, or 1/8” inch larger than the nominal pipe size.
9Copper Tubing Wall Thickness Copper water tube is available in three wall thicknesses designated as type K, L, and M in order of decreasing wall thicknesses.The outside diameter of K, L and M tubing are identical.This allows all three types of tubing to be compatible with the same fittings and valves.
10Copper M tubingBecause operating pressures of residential and light commercial hydronic heating systems are relatively low, the thinnest wall copper tube (type M) is most often used.This wall thickness provides several times the pressure rating of other common hydronic system components.
11Hard Drawn TubingTwo common hardness grades of copper water tube are available: hard drawn and soft drawn tubing.Hard drawn tubing is supplied in straight lengths of 10 and 20 feet.Because of its straightness and strength, hard drawn tubing is the most commonly used type of copper tubing in hydronic systems.
13Soft-Drawn Copper Tubing So-called soft drawn tubing is annealed during manufacturing to allow it to be formed with simple bending tools.It is useful in situations where awkward angles do not allow proper tubing alignment with standard fittings.
14AnnealingIn the cases of copper, annealing is performed by substantially heating the material (generally until glowing) and allowing it to cool.Unlike ferrous metals, which must be cooled slowly to anneal, copper can be cooled slowly in air or quickly by quenching in water. The metal is softened and prepared for further work, such as shaping, stamping, or forming.
16Hard Drawn Copper Tubing Support Horizontal runs of copper hard drawn tubing must be supported at a maximum of every 12’.Vertical runs of copper hard drawn tubing must be supported at a maximum of every 10’.Always refer to local code for proper spacing.
17Hard Drawn Copper Tubing Support These support spacings do not include any allowances for the extra weight of other system components, such as circulators or expansion tanks.When such components are present, the piping should be supported immediately adjacent to the component.
18Soft Drawn Copper Tubing Support Copper soft drawn tubing 1 ¼” and smaller on a horizontal run must be supported at a maximum of every 6’.Copper soft drawn tubing 1 ½” and larger on a horizontal run must be supported at a maximum of every 10’.Vertical spacing for all sizes is 10’.
19Pipe Support Materials A number of different supports are available for copper tubing.