Construction products. Assessment of release of dangerous substances - Guidance for the determination of leaching tests and additional testing steps

Construction products. Assessment of release of dangerous substances - Guidance for the determination of leaching tests and additional testing steps

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1   Scope

(1) This Technical Specification allows the identification of the appropriate leaching test method for the determination of the release of Regulated Dangerous Substances from construction products into soil, surface water and groundwater. This document provides a stepwise procedure for the determination of appropriate release tests, including:
  1. a) guidance for the identification of construction products potentially emitting Regulated Dangerous Substances;
  2. b) determination of the test method based on general product properties;
  3. c) choice of the test method using specific product properties.
(2) Furthermore, this Technical Specification gives general guidance for CEN Technical Product Committees on basic aspects (sampling, sample preparation and storage, eluate treatment, analysis of eluates and documentation) to be specified in the relevant product standards.
(3) Metallic products, coatings on metallic products and organic coatings for metals are not considered in the determination scheme of this Technical Specification since the test method in CEN/TS 16637‑2 (tank test) is not appropriate for the testing of these construction products due to a different release mechanism (solubility control).

NOTE Metallic products are excluded from the scope of CEN/TS 16637‑2 because the principles of that test (diffusion) are not obeyed by these products. Metallic products have shown pH dependent solubility control, which means that metals released from the oxidation layer on the metal until the maximum possible solubility level at the prevailing pH conditions in the surrounding water is reached (more water in contact with the same metal surface means more metals released and more time does not lead to more release due to solubility control). Maximum level of release can often be reached in minutes to hours. More generally, it can be stated that expression of results for metallic surfaces in mg/(m2·s) is always “conditional”, i.e. dependent on the local conditions at which the measurements were done, such as the volume of water relative to the surface area. For impact assessment, it is necessary to understand the above mentioned effects and to capture these effects in a test reflecting the dominant release mechanism. However, such a test method is currently unavailable. If the intrinsic leaching behaviour is known, release under specified local conditions could be determined by modelling. Furthermore, no notified regulations exist for metallic products at the time these Technical Specifications have been published.

(4) It is assumed that intermittent contact with water (e.g. exposure to rainwater) is tested - by convention - as permanent contact. For some coatings, (e.g. some renders with organic binders according to EN 15824) in intermittent contact to water, physical and chemical properties might be altered in permanent contact with water. These products are not considered in the determination scheme of this Technical Specification since the test method in CEN/TS 16637‑2 is not appropriate for the testing of these construction products.