The road to compliance with China RoHS is complicated. Being compliant with the European Union’s RoHS is not sufficient to guarantee compliance with China RoHS. In this Q&A, Roland Sommer, managing director of RoHS-International in New Zealand, explains some of the differences between EU RoHS and China RoHS when it comes to SMT resisters. This is the first of a three-part interview with Roland Sommer.

Design News: If your product is EU RoHS compliant, should you use the green China RoHS Logo?

Roland Sommer: The green China RoHS logo can only be used on EU RoHS compliant product if there are no banned substances in that product by exemption. This means that it is highly unlikely that any complex product will be able to use the green logo. The green logo will be used primarily for components.

DN: Could you explains why EU RoHS-compliant SMT resistors may not be China RoHS compliant? 

RS: SMT resistors typically contain lead oxide in the resistive layer and in the overcoating. This is allowed for EU RoHS by Exemption 5 (Lead in glass of cathode ray tubes, electronic components and fluorescent tubes) and Exemption 7 “Lead in electronic ceramic parts e.g. piezoelectronic devices.” While China RoHS treats components &4mm3 as a homogeneous material, the amount of lead may be in excess of this. Also it should be noted that the lead in SMT resistors is in the form of lead oxide (PbO). A multiplication factor of 0.928 must be applied to the PbO quantity to obtain the level of lead contained in the PbO.

Other components that will be EU RoHS compliant but will require China RoHS disclosure include: Mercury-containing backlights on LCDs, many turned brass, copper, aluminum and steel parts including fasteners (not cold-forged), many ICs >4mm3, some SMT thermistors and inductors.

If your product has even one component with one of the six hazardous elements or substance in it at concentrations above the limit values then the orange logo must be used, along with a disclosure table, date of manufacture and Environmentally Friendly Use Period.

DN: Will EU RoHS materials disclosures be sufficient for China RoHS?

RS: Neither China RoHS nor EU RoHS require manufacturers to amass material declarations or certificates of compliance for the sake of it. What manufacturers require is enough information to be able to be sure that the product that they are producing is compliant. In the EU case this requires removal of the 6 hazardous substances in all applications (apart from those with exemptions). For China, it requires disclosure of where the substances are, irrespective of whether they have an EU exemption. An EU RoHS yes/no certificate of compliance which does not disclose exemptions does not give sufficient information to determine the need for China RoHS declaration. If the manufacturer has enough expertise in component composition to determine how likely it is that a banned substance is in the component under EU exemption, then they can make a risk based assessment for the need for China RoHS Disclosure.

At the other end of the spectrum a full materials declaration gives all the information, but a manufacturer still has to assess the information against the regulatory requirements. We have seen many companies assume that if a component supplier supplies a full material composition disclosure then the item will be compliant. This is not always the case. It is up to each individual company to ascertain if a part is compliant for EU RoHS, or if it needs to be declared for China RoHS. When using material composition disclosures, a knowledge of chemistry is helpful as sometimes the substance will be part of a compound such as lead oxide. In this example manufacturers need to know how to calculate the lead (Pb) content of lead oxide.

The next article in this three-part series further explores differences between EU RoHS and China RoHS.