Some alloys can, including copper-beryllium, copper-chromium and copper-nickel-silicon. Most unalloyed coppers and brasses can only be softened by heating.
Yes. Copper tubes do not become brittle at low temperatures. The relevant standard is ‘Seamless round tubes for air conditioning and refrigeration’, BS EN 12735: 2010 Part 1: Tubes for Piping Systems, Part 2: Tubes for Equipment.
Yes they can be brazed by all processes. Appropriate silver brazing alloys should be used as phosphorus bearing brazing alloys cause a reaction with nickel to form a brittle phosphide phase.
Yes they can using appropriate 65% nickel-copper consumables to avoid iron dilution effects.
For smaller articles, a properly applied lacquer can be used, but this may need reapplying after a number of years. A specialist company must be consulted.
For architectural objects such as statues, natural waxes can used. These will need to be reapplied every few months.
For thorough prevention, it is possible to use both lacquer and wax.
For very large areas, such as copper roofing, patination prevention is generally not practical.
BS 369: 5 per cent phosphor bronze (copper-tin-phosphorus) rods and sections (other than forging stock) was withdrawn and replaced by:
BS 2874: Specification for copper and copper alloy rods and sections (other than forging stock) was withdrawn and replaced by:
BS EN 12163: Copper and copper alloys. Rod for general purposes and
BS EN 12164: Copper and copper alloys. Rod for free machining purposes and
BS EN 12167: Copper and copper alloys. Profiles and rectangular bar for general purposes.
The standards in bold are current.
Copper will not harden during storage; it does not have a shelf life.
Yes, more copper is needed during pregnancy (1mg/day) and when breast feeding (1.3mg/day).
Yes, at least once each year.
The number of the current European Standard for copper tubes is BS EN 1057.
‘BS B’ is an Aerospace spec for copper alloys. BS B 11 is ‘Brass bars suitable to be brazed or silver soldered’. BS B 11 was withdrawn in 1990 and not replaced. Brass bars are now specified in BS EN 12167.
Yes. Copper surfaces have been proven to have over 90% less contamination than conventional touch surfaces in hospital trials around the world. Trials have taken place, or are under way, in China, France, Germany, Greece, Japan, Spain, South Africa, Chile and the US.
Furthermore, in a multi-centre US trial, funded by the Department of Defense, copper surfaces were shown to reduce a patient’s risk of acquiring a healthcare-associated infection by 58%.