The European Union has introduced a directive that restricts the use of certain substances in Electrical and Electronic Equipment made in, or imported into the European Union. It comes into effect on 1 July 2006 and any equipment placed on the market after that date needs to comply. Called Restriction of use of certain Hazardous Substances in electrical and electronic equipment ( RoHS ) Directive, it restricts the use of: - Lead
- Mercury
- Cadmium
- Hexavalent Chromium
- Polybrominated biphenyls (PBB) Flame retardant
- Polybrominated diphenyl ethers (PBDE). Flame retardant The RoHS Directive effectively bans these substances from electrical and electronic products sold in Europe from July 1 2006. The maximum allowable amounts at homogeneous material level (see below for definition) are 0.1% for all except cadmium which is 0.01%. Up to these levels can be intentionally added. Examples of where these substances might be used include: Substance | Examples | Lead: | Tin-lead coatings, low temperature brazing alloys (SnPb), thermal stabilizers of PVC (lead stearate...), yellow pigments for polymers (lead chromate)… | Mercury | Mercury whetted relays | Cadmium: | Coatings (with hexavalent chromium passivation), high temperature brazing alloys (ex Ag-Cu-Zn-Cd…), thermal stabilizers of PVC (cadmium stearate...), yellow pigments for polymers (cadmium sulfide), | Hexavalent Chromium | Passivations of zinc, copper, alloys of aluminium, silver, galvanized sheet steel | Polybrominated biphenyls (PBB) | Flame retardant, cables, plastics | Polybrominated diphenyl ethers (PBDE) | Flame retardant, cables, plastics, ABS - Octa-BDE (Octabromodiphenyl ether) Polybrominated diphenol ether (PBDE)
- Penta-BDE (Pentabromodiphenyl ether) Pol
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There are numerous exemptions that have been granted and others are still under consideration. See the this link exemptions for more detail. Scope
The restrictions encompass most electrical and electronic devices. There are 8 broad categories: Large Household appliances Small house hold appliances IT and telecommumication equipment Consumer equipment Lighting Equipment (including electric light bulbs and househokd luminaires) Electrical and electronic tools (with the exception of large-scale stationary industrial tools) Toys, leisure and sports equipment Automatic dispensers
These categories are taken directly from annex 1 of the WEEE directive with two categories - Medical Devices and Monitoring and Control instruments excluded from scope at present, but under review. The recommendation from the official reviewer, ERA Technology, recommends inclusion of most Medical equipment and Monitoring and control equipment in 2012.. However a word of warning for monitoring and control devices. If your product is integrated into a product that is in scope, then your product will need to comply. A real life example, where a contract was lost, was for a temperature controller that was being supplied to a Swedish manufacturer of Industrial ovens. The controller on its own did not need to be RoHS compliant but in its application as a subcomponent of the industrial oven it needed to be. The company in question lost a sizable contract. Annex 1 of the WEEE Directive gives more detail on the equipment considered in scope Maximum Concentration Values (RoHS) There has been much debate regarding the interpretation of how much of each substance is allowed in a component and the exact meaning of the term "homogenous compound" used in the Directive. The following is from a guidance document from the Department of Trade and Industry in the UK. Although this is a draft it has been adopted by the European Commission -------------------------------- Maximum Concentration Values (RoHS) For the purposes of article 5(1)(a): a maximum concentration value of 0.1% by weight in homogeneous materials for lead, mercury, hexavalent, chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) and of 0.01% by weight in homogeneous materials for cadmium shall be tolerated. Homogeneous material means a material that cannot be mechanically disjointed into different materials. Definitions: The term "homogeneous" is understood as "of uniform composition throughout"> Examples of "homogeneous materials" are individual types of: Plastics, Ceramics, glass, metals, alloys, paper, board, resins, coatings. The term "mechanically disjointed" means that the materials can be, in principle, separated by mechanical actions such as for example: unscrewing, cutting, crushing, grinding and abrasive processes. Examples: - A plastic cover is a "homogeneous material" if it consists of one type of plastic that is not coated with or has attached to it or inside it any other kinds of materials. In this case the directive would apply to the plastic.
- An electric cable that consists of metal wires surrounded by non-metallic insulation materials is an example of a "non homogeneous material" because mechanical processes could separate the different materials. In this case the limit values of the directive would apply to each of the separated materials individually.
- A semi-conductor package contains many homogeneous materials which include; plastic moulding material, tin-electroplating coatings on the lead frame, the lead frame alloy and gold bonding wires.
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