Eight steps to China RoHS compliance

China RoHS is significantly different from the European Union's RoHS directive; however, there are significant benefits that can be gained by leveraging your company's compliance strategies for meeting the EU RoHS requirements. For example, the six restricted hazardous substances — lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) — are the same, as are the maximum concentration values (MCVs) in most cases. This means there is a good deal of leverage that be gained from the EU RoHS certificates of compliance, but there are still traps for the unwary regarding some EU RoHS exemptions.

Although China RoHS does not require the removal of hazardous substances it does require:

1. Labeling of product
2. A table in the user's guide disclosing the location of any hazardous substance above the maximum concentration levels (MCVs)
3. Calculation of the Environmentally Friendly Use Period (EFUP)
4. Labeling of the packaging

While all of the above requirements differ from the EU RoHS directive, there are eight basic steps that should be followed to adapt your company's EU RoHS compliance to meet China's RoHS requirements.

Step 1: Divide the product into logical subassemblies

The first step in complying with China RoHS is to divide the product into logical subassemblies. For a complex product, these will typically include individual printed circuit assemblies (PCAs), mechanical chassis, display (if any) and outer enclosure. All parts need to be accounted for in a logical and easily understood manner. These groups will form the "Components" portion of the disclosure table. Grouping of parts into "miscellaneous" or "other" is not allowed.

Key point #1:Disclosure is at the subassembly level not at the component level.

Step 2: Assess certificates of compliance

Once the "Components" (subassembly) have been populated in the table, the components that make up the subassemblies need to be analyzed for hazardous substances. This may seem like an onerous task but in fact it is much simpler than the EU requirements. Once any component in the subassembly has been found with a hazardous substance with a MCV greater than the limit, the table box can be marked with an "x" to indicate the presence of that substance. It is not necessary to list all components in the subassembly that contain the hazardous substance. An "x" in the table indicates that the subassembly contains one or more homogeneous materials with a concentration greater than the MCV.

Existing certificates of compliance for EU RoHS can be used to some degree to complete the disclosure table. There are two reasons why they will not fulfill all of the needs for China RoHS. First, there are some differences in the definition of homogeneous materials and the relative MCVs, and secondly not all certificates of compliance list the exemptions that have been claimed for EU RoHS. There are no exemptions for the China RoHS Disclosure except for DecaBDE. The basic definition of maximum concentration value is the same as the EU and is called category EIP-A.

However, China RoHS has created two new categories: EIP-B and EIP-C. The EIP-B category is defined as the limit value for a hazardous substance when used as a coating or treatment layer and cannot be intentionally added. This category was created to counter the arguments raised by the EU RoHS directive with the use of hexavalent chromium chromate and trivalent chromite processes. This may have some implications for disclosure for certain colors of paint where the hazardous substances are intentionally used in concentrations of less than 1000 ppm (100 ppm for cadmium) in the pigment.

Key point #2: The hexavalent chromium-based chromate process requires disclosure, but the trivalent chromium-based chromite process does not need to be disclosed. Any hexavalent chromium generated in the trivalent process has not been added intentionally.

Category EIP-C defines any component of mass equal to or smaller than 4 mm3. This will cover most SMT passive components.

Key point #3: Be wary of the EU exemption for lead in glass of electronic components. Many RoHS declarations for EU RoHS do not state if an exemption has been claimed. Many, if not most, SMT passive components, even if RoHS compliant, may still have concentrations of lead in excess of 1000 ppm at the component level due to lead oxide in the resistive layer, capacitive substrate, conductive layer and coating layer. As a result, most PCAs will have lead content.

Step 3: Populate the disclosure table

After assessing each subassembly for the presence of each hazardous substance in concentrations greater than the MCV, the table needs to be populated. An "x" indicates the presence of a hazardous substance and an "o" indicates the absence, or presence of hazardous substances at concentrations below the MCVs. The table needs to be written in (or translated into) Chinese, but the "x" and "o" can be shown in Western fonts.

Disclosure table
(Click on Image to Enlarge)

Key point #4:The disclosure is a binary yes/no disclosure that indicates that one homogeneous material within the subassembly according to the EIP-A, B and C definitions exceeds the MCVs. The actual concentration level does not need to be disclosed.

Key point #5: If no hazardous substances are contained at concentrations above the MCV in any part of the product then the disclosure table is not needed. This would probably only apply to simple components, not to complex products.