Restriction of Hazardous Substances (RoHS) is an EU directive that limits the use of certain hazardous materials found in electronic or mechanical components. Sensor and transducer suppliers must cooperate with RoHS specifications for products to be made available on EU markets. These specifications have changed over the years with new and emerging materials requiring restriction for use in commercial applications. The original six substances that were controlled and restricted by RoHS were:
- Cadmium (Cd);
- Hexavalent Chromium (Cr VI);
- Lead (Pb);
- Mercury (Hg);
- Polybrominated Biphenyls (PBB);
- Polybrominated Diphenyl Ethers (PBDE).
Sensor and transducer suppliers that utilize these substances in the manufacture of mechanical or electronic components must ensure that their levels remain below 1000 ppm of the homogenous material in the product. This excludes mercury and lead, which are controlled at more stringent levels of below 100 ppm.
RoHS 3 is an addition to the directive, adding four more restricted substances for sensor and transducer suppliers to limit in component applications:
- Bis(2-Ethylhexyl) phthalate (DEHP);
- Benzyl butyl phthalate (BBP);
- Dibutyl phthalate (DBP);
- Diisobutyl phthalate (DIBP);
Each of these plasticizers was added to the directive in 2015. They are subject to a grace period, to allow sensor and transducer suppliers time to comply with the new regulation. All EU monitoring and control equipment must keep component quantities of the above substances below 1000 ppm by 2021 to comply with RoHS 3.