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Paragraph 8 of entry 23 of Annex XVII to the REACH Regulation states that cadmium and its compounds shall not be used in brazing fillers in a concentration equal to or greater than 0,01 % by weight. In addition, brazing fillers shall not be placed on the market if the concentration of cadmium (expressed as Cd metal) is equal to or greater than 0,01 % by weight. The paragraph also states that brazing shall mean a joining technique using alloys and undertaken at a temperature above 450°C. In accordance with the following paragraph 9, by way of derogation paragraph 8 shall not apply to brazing fillers used in defence and aerospace applications nor to brazing fillers used for safety reasons.
The safety aspect in relation to this derogation is if the use of cadmium containing brazing filler may prevent accidents causing human suffering or environmental pollution.
For the enforcement purposes examples of applications are given. It can be considered that the derogation on uses of cadmium containing brazing fillers for safety reasons in paragraph 9 of entry 23 covers the current uses, such as:
- Brazing fillers used in turbine wheels in power plant technology in temperature below 650°C.
Turbine wheels in power plant technology are parts of speed drivers for gas compressors and boiler feed pumps, where rotational speed is approximately from 1000 revolutions per minute (rpm) up to 20 000 rpm. Cadmium containing brazing fillers are needed as they can be used below 650 °C without decreasing the strength of the parent material (base metal). Cadmium-free brazing fillers require higher temperatures which causes the weakening of the parent material. Weakening of the parent material could lead to the breakdown of the turbine wheel. Due to high rotational speed the parts and pieces of shrapnel may cause injuries to workers and others in the vicinity of the wheel. The breakdown of the turbine wheel may result also in a complete shutdown of the power plant, the compressor station of a gas pipeline, or of a refinery.
- Brazing fillers used in pipes and tubes where acetylene is transferred in high pressure (1.5 – 17 bar).
Cadmium containing brazing fillers are needed in the joining process for pipes and tubes, where acetylene is transferred in order to avoid formation of explosive substances. Acetylene forms explosive substances with copper and silver as well as other materials (e.g. formation of copper acetylide and silver acetylide). Cadmium reduces the overall percentage of copper and silver in the brazing fillers to the level where formation of explosive substances does not exist. Another reason to use cadmium in brazing fillers for this application is that cadmium facilitates the capillary action and solder penetration ensuring a good quality joint with high integrity for pipes and tubes where acetylene is transferred in high pressure (1.5-17 bar). Release of acetylene from pipes and tubes may as well cause serious risk, as acetylene is extremely flammable gas and explosive with and without contact with air.
Other applications that would like to benefit from the derogation need to show the similar kind of safety aspects as described above.
Such considerations should take into account the availability on the market of cadmium-free brazing fillers which can address the safety aspects of the specific application of the brazing fillers in an equivalent manner.
See also ECHA´s report "The use of brazing fillers containing cadmium for safety reasons" [PDF].