Wednesday, October 7, 2009

What is RoHS?

RoHS is short for Restriction of Hazardous Substances Directive (RoHS) and was adopted in February 2003 by the European Union. The RoHS took effect on July 1, 2006, but is not a law; it is simply a directive for participating countries, including the European Union (exclusive of the United States and many other countries)


This directive restricts the use of six hazardous materials in the manufacture of various types of electronic and electrical equipment.
RoHS is often referred to as the "lead-free" directive, but it restricts the use of the following 6 substances:

Lead
Mercury
Cadmium
Hexavalent
chromium (Chromium VI or Cr6+)
Polybrominated
biphenyls (PBB)
PBDE (polybrominated diphenyl ether)


It is closely linked with the Waste Electrical and Electronic Equipment Directive WEEE 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.

The maximum permitted concentrations are 0.1% or 1000 ppm (except for cadmium, which is limited to 0.01% or 100 ppm) 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. The screws, washers, and case may each be made of homogenous materials, but the other components comprise multiple sub-components of many different types of material. For instance, a circuit board comprises a bare PCB, ICs, resistors, capacitors, switches, etc. A switch comprises a case, a lever, a spring, contacts, pins, etc, each of which may be made of different materials. A contact might comprise a copper strip with a surface coating. A speaker comprises a permanent magnet, copper wire, paper, etc.

Everything that can be identified as a homogeneous material must meet the limit. So if it turns out that the case was made of plastic with 2,300 ppm (0.23%) PBB used as a flame retardant, then the entire radio would fail the requirements of the directive.

In an effort to close RoHS loopholes, in May 2006 the European Commission was asked to review two currently excluded product categories (monitoring and control equipment, and medical devices) for future inclusion in the products that must fall into RoHS compliance. In addition the commission entertains requests for deadline extensions or for exclusions by substance categories, substance location or weight. Note that batteries are not included within the scope of RoHS. However, in Europe, batteries are under the European Commission's 1991 Battery Directive (91/157/EEC), which was recently increased in scope and approved in the form of the new battery directive, version 2003/0282 COD, which will be official when submitted to and published in the EU's Official Journal. While the first Battery Directive addressed possible trade barrier issues brought about by disparate European member states' implementation, the new directive more explicitly highlights improving and protecting the environment from the negative effects of the waste contained in batteries. It also contains a program for more ambitious recycling of industrial, automotive, and consumer batteries, gradually increasing the rate of manufacturer-provided collection sites to 45% by 2016. It also sets limits of 5 ppm mercury and 20 ppm cadmium to batteries except those used in medical, emergency, or portable power-tool devices, Though not setting quantitative limits on quantities of lead, lead-acid, nickel, and nickel-cadmium in batteries, it cites a need to restrict these substances and provide for recycling up to 75% of batteries with these substances. There are also provisions for marking the batteries with symbols in regard to metal content and recycling collection information.

The directive applies to equipment as defined by a section of the WEEE directive. The following numeric categories apply:

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.
Medical devices
Monitoring and control instruments
Automatic dispensers.


It does not apply to fixed industrial plant and tools. Compliance is the responsibility of the company that 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. It is enabled through two PDF forms that are free to use.

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

Examples of product components containing restricted substances RoHS restricted substances have been used in a broad array of consumer electronics products. Examples of leaded components include:

Paints and pigments
PVC (vinyl) cables as a stabilizer (e.g. power cords, USB cables)
Solders
Printed circuit board finishes, leads, internal and external interconnects
Glass in television and photographic products (e.g. CRT television screens and camera lenses)
Metal parts
Lamps and bulbs

Cadmium is also found in many of the above components while mercury has been used in automotive switches and lighting applications. Hexavalant chromium is used for metal finishes to prevent corrosion. Polybrominated biphenyls and diphenyl Ethers/Oxides are used primarily as flame-retardants.

California has passed SB 20: Electronic Waste Recycling Act of 2003, or EWRA. This law prohibits the sale of electronic devices after January 1, 2007, that are prohibited from being sold under the EU RoHS directive, but across a much narrower scope that includes LCDs, CRTs, and the like and only covers the four heavy metals restricted by RoHS. EWRA also has a restricted material disclosure requirement. Other US states and cities are debating whether to adopt similar laws, and there are several states that have mercury and PBDE bans already. Federal RoHS-like regulation in the US is unlikely in the near to medium term.