Dow and REACH - Use Descriptor System - A System to Describe Uses

ECHA has developed a system to describe uses (the so-called Use Descriptor System: UDS). The UDS aims at standardizing the description of uses in the supply chain. This will support the identification of uses and facilitate the communication of uses up and down the supply chain. The guidance on this UDS can be downloaded from the ECHA website.

This document gives an explanation of this system and guidance on how to use this system.

The UDS is based on five separate descriptors,

  1. Sector of Use (SU)
  2. Process Category (PROC)
  3. Product Category (PC)
  4. Article Category (AC) 
  5. Environmental Release Category (ERC)


For each of these descriptors (coded) categories have been developed. The combination of categories selected from each of the descriptor lists results in a brief description of the use. In general a description of a use will also contain a short use title.


2.	Use Descriptor System 

Figure 1: Diagram of the Use Descriptor System (ECHA, 2008; with modifications)


Figure 1 shows what the five descriptors are reflecting and how these descriptors are related to each other.

  1. Sector of Use (SU): describes in which sector the substance is used. The three main user categories (SU3: industrial; SU21: consumer; SU22: professional) represent the minimum of information needed to describe the sector.
    SU3: Industrial uses: Uses of substances as such or in preparations at industrial sites
    SU9: Manufacture of fine chemicals
    SU21: Consumer uses: Private households (= general public = consumers)
    SU22: Professional uses: Public domain (administration, education, entertainment, services, craftsmen
  2. Process Category (PROC): describes the application techniques or process types defined from an occupational perspective; the PROC, in combination with the operational conditions and risk management measures, is the prime determinant for the level of occupational exposure.
    PROC2: Use in closed, continuous process, with occational controlled exposure
    PROC5: Use in batch or other process (synthesis) where opportunity for exposure arises
    PROC7: Industrial spraying
    PROC8a: Transfer of substance or preparation (charging/discharging) from/to vessels/large containers at dedicated facilities

  3. Product Category (PC): describes the types of chemical products in which a substance is used. The PC in combination with the operational conditions and risk management measures primarily determines the level of consumer exposure. For the level of occupational exposure the Process Category is much more relevant.
    PC9a: Coatings and paints, thinners, paint removers
    PC24: Lubricants, greases, release products
    PC31: Polishes and wax blends
    PC39: Cosmetics, personal care products

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  4. Article Category (AC): describes the type of article in which the substance has been processed. The AC as such has no impact on the exposure. Where articles containing substances are processed by workers, it is mainly the PROC descriptor again that determines the level of exposure. Consequently for consumers the PC is the key descriptor for determining the exposure.
    AC2: Machinery, mechanical appliances, electrical/electronic articles
    AC13: Plastic articles
    AC35: Scented paper articles
    AC38: Packaging material for metal parts, releasing grease/corrosion inhibitors

  5. Environmental Release Category (ERC): describes the broad conditions of use from an environmental perspective, based on those characteristics that give a first indication of the potential release of the substance to the environment. Note that the ERC 1 to 7 and 12 are related to industrial activities, while the ERC 8 to 11 are related to consumer or professional uses.
    ERC2: Formulation of preparations
    ERC6a: Industrial use resulting in the manufacture of another substance (use of intermediates)
    ERC8a: Wide dispersive indoor use of processing aids in open systems
    ERC11b: Wide dispersive indoor use of long-life articles and materials with high or intended release (including abrasive processing)

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