e3 Toolkit - What are the WEEE and RoHS Directives?

What are the WEEE and RoHS Directives? / FAQs for RoHS

FAQs for RoHS

What is the RoHS Directive?

What is the objective of the RoHS Directive?

What are the key provisions of the Directive?

Does the RoHS directive cover the same categories of equipment as the WEEE Directive?

At what levels will an item be deemed to be free of the proscribed materials?

What is an homogenous material?

Are products intended for military and aerospace use subject to the RoHS Directive?

When changing over to Lead-Free alloys for soldering will new equipment be needed?

Which brominated flame retardants will be proscribed by the RoHS Directive?

What do you need to do?

What is the biggest challenge associated with RoHS compliance?

Will Lead-Free components be widely available?

What is the RoHS Directive?

This European Directive aims to restrict the use of some substances deemed to be hazardous in electrical and electronic equipment.

The Restriction of the use of certain Hazardous Substances in electrical an electronic equipment (RoHS) Directive aims to ensure harmonisation of legislation controlling hazardous substances used in electrical and electronic equipment across the EEA, and to limit the environmental impact of electrical and electronic equipment when it reaches the end of its life through the minimisation of the use of specific hazardous substances.

What are the key provisions of the Directive?

The RoHS Directive restricts the use of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls (PBBs) and two types of polybrominated diphenylethers (PBDEs). The brominated substances are used as flame retardants in plastics. The restrictions came into force on 1st July 2006. There is a list of exempted uses for some of these substances where substitutes are not yet available or where it is not technically feasible to find substitutes. It is possible that additional materials may also be proscribed if they are deemed unacceptable by a review committee.

There are eight categories of products that are specifically covered by the RoHS directive. The medical, defence and aerospace categories are exempted by omission. The categories listed essentially cover products purchased by the general public i.e. high volume, low cost products:

Large household appliances

Small household appliances

IT and telecommunication equipment

Consumer equipment

Lighting equipment

Electrical and electronic tools

Toys (including leisure and sports equipment)

Automatic dispensers

These are only indicative categories, and the list will be reviewed and may be altered in the future as more data on the impact on the environment and human health of other hazardous materials becomes available. A study on Monitoring and Control equipment and medical devices has been undertaken and it has recommended that they come into the scope of RoHS by 2012.

To be compliant with the legislation, each of the proscribed substances must be removed or reduced to below the individual maximum permitted concentrations that are as follows;

0.1% by weight per homogeneous material for lead, hexavalent chromium mercury, PBBs and PBDEs.

0.01% by weight and per homogeneous material for cadmium.

What is an homogenous material?

'Homogeneous material' is a material that cannot be mechanically disjointed into different materials.

The term 'homogeneous' is understood as being 'of uniform composition throughout', so examples of 'homogeneous materials' would be individual types of plastics, ceramics, glass, metals, alloys, paper, board, resins and coatings.

The term 'mechanically disjointed' means that the materials can be, in principle, separated by mechanical actions such as unscrewing, cutting, crushing, grinding and abrasive processes.

Using these interpretations, a plastic cover (for example) is considered a 'homogeneous material' if it consists exclusively of one type of plastic that is not coated with or has attached to it (or inside it) any other kind of material. In this case, the maximum concentration values of the RoHS Regulations would apply to the plastic. However, an electric cable that consists of metal wires surrounded by non-metallic insulation materials is an example of something that is not 'homogeneous material' because mechanical processes could separate the different materials. In this case the maximum concentration values of the RoHS Regulations would apply to each of the separated materials individually.

Products with applications that can be considered exclusively for aerospace are not covered by the scope of either the RoHS or WEEE directives. The WEEE directive also states that equipment connected with national security or military purposes is excluded from the scope of the directive. The government considers that the RoHS Directive is broadly reflected in the WEEE Directive and so this exemption will apply equally to products covered by this Directive. However, the exemption will not apply to products in the eight categories which can be used in connection with either military or civilian applications.

It depends on a number of factors including the choice of Lead-Free solder. One alloy that is likely to find widespread use is based on tin, silver and copper. Tin-silver-copper (SnAgCu) alloys melt in the region of 215 to 220ºC, which is more than 30 degrees higher than conventional tin-lead solders. Use of SnAgCu solder will result in a narrower process window and process controls will have to be tightened. Depending on which equipment is to be used and the type of assemblies being soldering, new equipment may need to be purchase. For example, with the higher soldering temperatures it may be necessary to consider pre-heating for the larger components. For reflow soldering, convection ovens are preferred to infra-red ovens because they can provide better temperature control and adequate temperature range. The use of nitrogen inerting may also be required to widen the process window. Wave soldering equipment may also need to be modified to avoid damage at the higher soldering temperatures. Solder pot corrosion may be an issue and, as with reflow soldering, nitrogen inerting may be required to widen the process window. Few problems are expected with hand soldering operations and generally, no new equipment should be necessary.

The RoHS Directive only bans polybrominated biphenyls (PBBs), penta-bromodiphenyl ether, octa-bromodiphenyl ether and tetra-bromodiphenyl ether out of the more than 70 brominated flame retardants. Other brominated flame retardants may, however, be included at a later date if subsequent testing indicates they could be causing problems. The brominated flame retardants based on bisphenol A, which are widely used in printed circuit board laminates, are not included in the RoHS directive and thus may continue to be used for the immediate future. It is quite possible that this situation may change at a later date and many laminate manufacturers are developing bromine-free laminates as alternatives.

All products, sub-assemblies and components likely to be impacted by the RoHS Directive should be audited to identify if, and where, restricted substances are used. Suppliers should be contacted to confirm that there are no proscribed substances used in their products or, if there are, to determine how these will be replaced with compliant ones in time to meet the requirements of the directive. Customers should also be advised of the actions being taken to comply with the legislation. Consulting with customers on proposed product changes will help improve the products you offer. Consulting with the supply-chain now will help to anticipate and reduce the ‘end-of-life’ costs of your products. It might avoid having to replace non-compliant products or components with expensive alternatives.

The biggest challenge for many producers when attempting to comply with the requirements of the RoHS Directive is in identifying where the banned materials have traditionally been used. The implications of not knowing what is in an individual component could mean that some products have to be taken off the market. Producers should proactively develop a dialogue with their suppliers to advise of this and to determine if any of the components they sell contain any of the banned materials. For lead, the application areas are well defined and relatively limited in scope but for some of the other proscribed substances there is a much broader range of applications where they may be found and some of these may not be so immediately obvious. For example, cadmium, which is used in some solders and as an electroplated corrosion resistant coating may also be used as a pigment for plastics used as wire insulation and in cathode ray tube phosphors.

Although the supply of lead-free components has been slow to develop, most component manufacturers and their distributors have strategic roadmaps to comply with the legislation. However, there is likely be a variation in lead-free component availability, with high usage and cheaper components having lead-free terminations becoming available earlier than some other niche or expensive components with lead-free terminations. It will be important to ensure that the change to lead-free components and the use of lead-free board finishes is carried out before changing to lead-free solder. The reason for this approach is that there are no major concerns with using lead-free board and component finishes with lead containing solder. However, the same is not true for the converse situation and joint reliability can be seriously impacted.

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