1. HVAC523
Piping and Fittings

2. Copper tubing
Copper tubing was developed in the 1920s to provide an alternative to iron piping in a variety of uses.

3. Desirable features
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

4. Desirable features
Lighter than steel or iron piping of equivalent size.
Ability to be joined by the well-known technique of soft soldering

5. Copper pipe size
Copper 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.
In the United States, copper water tube is manufactured according to strict standards.

6. ASTM B88 This standard is known as ASTM B88.
American Society for Testing and Materials

7. ASTM B88
According 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.

8. Copper tube sizing
The outside diameter of copper water tubing is always 1/8” inch larger than the nominal inside diameter.
For example, the outside diameter (O.D.) of ¾” inch type M copper tubing is .875 inches
This is exactly 7/8” inches, or 1/8” inch larger than the nominal pipe size.

9. Copper 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.

10. Copper M tubing
Because 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.

11. Hard Drawn Tubing
Two common hardness grades of copper water tube are available.
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.

12. Hard drawn copper Tubing

13. Soft 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.

14. Annealing
In the cases of copper this process is performed by substantially heating the material (generally until glowing) for a while 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. In this fashion the metal is softened and prepared for further work such as shaping, stamping, or forming.

15. Annealed copper tubing

16. Hard 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

17. Hard 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.

18. Soft 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’

19. Pipe support materials
A number of different supports are available for copper tubing.

20. Split rings
Adjustable strap
2 hole pipe strap
Clevis hanger
J hook
Bell hanger

21. Pipe insulator
Two hole plastic strap
Strut cushion clamp
Copper strap
Vertical pipe support

22. Common pipe fittings
Many of the pipe fittings used in hydronic systems are the same as used in conventional water supply systems.

23. Couplings: (standard and reducing)
Reducer coupling

24. Elbows: 90 degree and 45 degree

25. Street elbows: (90 and 45 degrees)

26. Tees: (Standard and reducing)
Reducing Tee

27. Threaded adapters: (Male and female)
Male adapter
Female adapter

28. Unions

29. Ball valves
Sweat ball valve
NPT ball valve

30. Gate valve

31. Boiler drain valve

32. Boiler Drain T

33. Baseboard elbow