RoHS

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The Restriction of Hazardous Substances Directive (RoHS) 2002/95/EC was adopted in February 2003 by the European Union. The RoHS directive took effect on July 1, 2006, but is not a law; it is simply a directive. This directive restricts the use of six hazardous materials in the manufacture of various types of electronic and electrical equipment. It is closely linked with the Waste Electrical and Electronic Equipment Directive (WEEE) 2002/96/EC which sets collection, recycling and recovery targets for electrical goods and is part of a legislative initiative to solve the problem of huge amounts of toxic e-waste. In casual conversation, it is often pronounced "ROSH", or "Row Haws".

Details

Each European Union member state will adopt its own enforcement and implementation policies using the directive as a guide. Therefore, there could be as many different versions of the law as there are states in the EU.

RoHS is often referred to as the "lead-free" directive, but it restricts the use of the following 6 substances:

Lead
Mercury
Cadmium
Chromium VI (Also known as hexavalent chromium or Cr6+)
PBB
PBDE

PBB and PBDE are flame retardants used in some plastics.

The maximum concentrations are 0.1% (except for Cadmium which is limited to 0.01%) by weight of homogeneous material. This means that the limits do not apply to the weight of the finished product, or even to a component, but to any single substance that could (theoretically) be separated mechanically — for example, the sheath on a cable or the tinning on a component lead.

As an example, a radio comprises a case, screws, washers, a circuit board, speakers etc. A circuit board comprises a bare PCB, ICs, resistors, switches etc. A switch comprises a case, a lever, a spring, contacts, pins etc. The contact might comprise a copper strip with a surface coating.

Everything that can be identified as a different material must meet the limit. So if it turns out that the case was made of plastic with 2300 ppm (0.23%) PBB used as a flame retardant, then the entire radio would fail the requirements of the directive.

Note that batteries are not included within the scope of RoHS, therefore NiCd, Lead-acid and Mercury batteries are permitted despite the use of restricted substances.

The directive applies to equipment as defined by a section of the WEEE directive. These are:

Large and small household appliances.
IT equipment.
Telecommunications equipment (although infrastructure equipment is exempt in some countries)
Consumer equipment.
Lighting equipment — including light bulbs.
Electronic and electrical tools.
Toys, leisure and sports equipment.
Automatic dispensers.

It does not apply to fixed industrial plant and tools. Compliance is the responsibility of the company which puts the product on the market, as defined in the Directive; components and sub-assemblies are not responsible for product compliance. Of course, given the fact that the regulation is applied at the homogeneous material level, data on substance concentrations needs to be transferred through the supply chain to the final producer. An IPC standard has recently been developed and published to facilitate this data exchange, IPC-1752 http://www.ipc.org/ipc-175x . It is enabled through two Adobe forms which are free to use.

RoHS applies to these products in the EU whether made within the EU or imported. Certain exemptions apply, and these are updated on occasion by the EU.

There is also legislation in China (often referred to as "China RoHS") that has similar restrictions. Unlike EU RoHS (products are included unless specifically excluded), there will be a list of products to which the regulations apply (products are excluded unless specifically included). There are some products which probably will be included for China RoHS which are not in scope for EU RoHS - e.g. radar systems. However, the details of the requirements and list of included products have not been finalized by the Chinese government. The legislation is scheduled to take effect 1 March 2007.

Japan does not have any direct legislation dealing with the RoHS substances, but its recycling laws have spurred the Japanese manufacturers to move to a lead-free process. These companies have also been proactive in phasing out other harmful materials which will, in effect, make their products RoHS compliant.

In addition, California and other US states and cities are debating whether to adopt similar laws.

Criticism

The expense of compliance, especially to cottage industry, and impact on product quality are cited as criticisms of the directive. Restricting lead content in solders for electronics requires expensive retooling of the assembly lines and different coatings for the leads of the electronic parts. The alternatives to the solders typically have higher melting points (up to 260 °C, instead of just 215 °C), requiring different materials for chip packagings and for some circuitboards; the overheating may also affect reliability of semiconductors designed for the older temperatures. The alternative solders are also harder, resulting in slow development of cracks (instead of plastic deformation, as the softer Sn-Pb solder does) because of thermal expansion and contraction as some parts heat up and cool down during operation, thus significantly impairing long-term reliability and device lifetime.^{[citation needed]} Another problem that lead-free solders face is the growth of tin whiskers. These strands of tin can grow and make contact with an adjacent trace, developing a short circuit. Tin whiskers have already been responsible for at least one faliure at a nuclear power plant. [1] Some countries therefore tend to exempt medical and telecommunication infrastructure products from the legislation. [2] There are no de minimus exemptions e.g. for micro-businesses, meaning that some cottage industries have had to close down, citing the cost of compliance.[3]

The US EPA has published a life cycle analysis which compares lead-free and lead solder in terms of environmental impact.[4] Essentially, the lead-free alternatives appear to have a more negative impact on the environment than the leaded solders. Another life-cycle assessment [5] by IKP, University of Stuttgart, comes to the same result.

Literature

Introduction to Implementing Lead-Free Electronics by Jennie S. Hwang. (2004) McGraw-Hill Professional, ISBN 0071443746.

External links

Details

Criticism

Literature

See also

External links