It is up to the designer to select the type of copper tube for use in a particular application. Strength, formability and other mechanical factors often determine the choice. Plumbing and mechanical codes govern what types may be used. When a choice can be made, it is helpful to know which type of copper tube has and can serve successfully and economically in the following applications:
- Underground Water Services
Use Type M hard for straight lengths joined with fittings, and Type L soft where coils are more convenient.
- Water Distribution Systems
Use Type M for above and below ground.
- Chilled Water Mains
Use Type M for all sizes.
- Drainage and Vent Systems
Use Type DWV for above- and below-ground waste, soil and vent lines, roof and building drains and sewers.
For radiant panel and hydronic heating and for snow melting systems, use Type L soft temper where coils are formed in place or prefabricated, Type M where straight lengths are used. For water heating and low-pressure steam, use Type M for all sizes. For condensate return lines, Type L is successfully used.
- Solar Heating
See Heating section above. See also Solar Energy Systems. For information on solar installation and on solar collectors, contact CDA.
- Fuel Oil, L.P. and Natural Gas Services
Use Type L or Type ACR tube with flared joints in accessible locations and brazed joints made using AWS A5.8 BAg series brazing filler metals in concealed locations.
- Nonflammable Medical Gas Systems
Use Medical Gas tube Types K or L, suitably cleaned for oxygen service per NFPA Standard No. 99, Health Care Facilities.
- Air-Conditioning and Refrigeration Systems
Copper is the preferred material for use with most refrigerants, including newer, natural refrigerants like CO2, propane, isobutane and others (copper is not recommended for use with ammonia). Use Types L, ACR or as specified. In designing and installing HVACR systems the use of long-radius 90-degree elbows is recommended. Long-radius elbows reduce pressure drop by 15 - 20 percent over standard and short-radius elbows (see Table 14.7a).
- Ground Source Heat Pump Systems
Use Types L or ACR where the ground coils are formed in place or prefabricated, or as specified.
- Fire Sprinkler Systems
Use Type M hard. Where bending is required, Types K or L are recommended. Types K, L and M are all accepted by NFPA.
- Low Temperature Applications
Use copper tube of Type determined by rated internal working pressures at room temperature as shown in Tables 14.3a-e. Copper tube retains excellent ductility at low temperatures to -452° F and yield strength and tensile strength increase as temperature is reduced to this point. This, plus its excellent thermal conductivity, makes an unusual combination of properties for heat exchangers, piping, and other components in cryogenic plants and other low temperature applications.
- Compressed Air
Use copper tube of Types K, L or M determined by the rated internal working pressures as shown in Tables 14.3a-c, e. Brazed joints are recommended.