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 any given application.
Because of its exceptional formability, copper can be formed as desired at the job site. Copper tube, properly bent, will not collapse on the outside of the bend and will not buckle on the inside of the bend. Tests demonstrate that the bursting strength of a bent copper tube can actually be greater than it was before bending.
Because copper is readily formed, expansion loops and other bends necessary in an assembly are quickly and simply made if the proper method and equipment are used. Simple hand tools employing mandrels, dies, forms and fillers, or power-operated bending machines can be used.
Both annealed tube and hard drawn tube can be bent with the appropriate hand benders. The proper size of bender for each size tube must be used.
Soldered joints, with capillary fittings, are used in plumbing for water lines and for sanitary drainage. Brazed joints, with capillary fittings, are used where greater joint strength is required or where service temperatures are as high as 350° F. Brazing is preferred, and often required, for joints in refrigeration piping.
Mechanical joints are used frequently for underground tubing, for joints where the use of heat is impractical and for joints that may have to be disconnected from time to time. Copper tube may also be joined by butt-welding without the use of fittings. Care must be taken to use proper welding procedures.
For additional information on all aspects of installing copper piping systems, please refer to the Copper Tube Handbook.