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.

ECHA has published a new version of the UDS in December 2015. The first version of the UDS was based on six separate descriptors:

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

In the updated UDS version an additional descriptor is introduced: Life Cycle Stage (LCS). This descriptor reflects the whole life-cycle of a substance. There are four basic stages in the life-cycle of a substance to which a use can be assigned: manufacture, formulation or repacking, end-use and (article) service life, as illustrated below.

 

The diagram below shows what the original five use descriptors are reflecting and how these descriptors are related to each other (ECHA, 2008, with modifications):

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

For the substances registered in 2010 and 2013 Dow has utilized the first version of the UDS with the five use descriptors to describe the uses.

For the registration of substances in the 2018 timeline Dow will adopt the updated version of the UDS.

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 use title.

  1. Life Cycle Stage (LCS): the life cycle stage reflects the stage of the chemical in its life cycle. It is structured in such a way that it indicates the type of organizations using the chemical after its manufacture (e.g. formulators, industrial end users, etc). The LCS consists of 6 (coded) stages:
    M: Manufacture
    F: Formulation or re-packing
    IS: Use at industrial sites
    PW: Widespread use by professional workers
    C: Consumer use
    SL: Service Life
  2. Sector of Use (SU): describes in which sector or market area the substance is used.
    Examples:
    SU4: manufacture of textiles, leather, fur
    SU9: manufacture of fine chemicals
    SU11: manufacture of rubber products

    Note: in the previous version of the UDS so-called Main User Groups (MUG) were used to indicate the setting of the use (SU3: industrial; SU22: professional; SU21: consumer). The MUG has not been maintained in the updated version of the UDS (replaced by the Life Cycle Stage (LCS)).

  3. 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. It is a required descriptor for worker uses. Examples:
    PROC1: Chemical production or refinery in closed process without likelihood of exposure or processes with equivalent containment conditions
    PROC5: Mixing or blending in batch processes
    PROC7: Industrial spraying
  4. Chemical Product Category (PC): describes the types of chemical products in whicha substance is used. The PC in combination with the operational conditions and risk management measures primarily determines the level of consumer exposure. It is a required descriptor for consumer uses.
    Examples:
    PC9a: Coatings and paints, thinners, paint removers
    PC24: Lubricants, greases, release products
    PC31: Polishes and wax blends
  5. 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. The AC is only relevant and should only be used for the life-cycle stage Service Life (SL).
    Examples:
    AC2b: Other machinery, mechanical appliances, electrical/electronic articles
    AC8e: Paper articles: Furniture & furnishings
    AC13a: Plastic articles: large surface area articles
  6. 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 ERCs in the range of 1 to 7 are related to activities on industrial sites, while ERCs in the range of 8 to 9 are related to activities by professional workers and consumers. The ERCs in the range of 10 to 12 are related to service life. The default is to select only one ERC per use.
    Examples:
    ERC2: Formulation into mixture
    ERC6a: Use of intermediate
    ERC8a: Widespread use of non-reactive processing aid (no inclusion into or onto article, indoor)