CEN/TC 351/WG 1 - Release from construction products into soil, ground water and surface water

This document describes the pros and cons for the different methods for reporting the potential release of dangerous substances into soil, groundwater or surface water and indoor air, which are:
—   level (or declared values); and
—   classes;
as defined in the Construction Products Regulation (CPR).
In addition, the pros and cons of additional methods based on discussion in CEN/TCs and WGs are described, which are:
—   categories; and
—   manufacturer’s declaration.

1) This document specifies a test procedure that combines horizontal leaching tests with ecotoxicity tests for the assessment of eluates of the construction products specified in this scope subjected to wet conditions in outdoor use.
2) The method specified in this document is intended for the determination of the potential ecotoxicity of eluates extracted out of construction products containing constitutional organic components of main categories of product matrices P (plastics and rubbers), A (sealants and adhesives) or C (paints and coatings) according to CEN/TR 16045.
3) Construction products mainly made of inorganic materials: main categories of product matrices S (silica-based and calcareous products) and M (metals) according to CEN/TR 16045 are excluded, unless:
- the liquid or paste product hardens in direct contact with soil or groundwater; and
- the used binder contains > 50 % organics by mass.
NOTE 1 This exception mainly refers to products used for soil injection and stabilization, e.g. grouts.
Also, the method is not intended for construction products made of treated or untreated solid wood in main category of product matrix W (wood-based products) according to CEN/TR 16045. For engineered bio-based products the test procedure can be of interest.
4) This document is not applicable for the assessment of terrestrial ecotoxicity of construction products.
NOTE 2 Terrestrial ecotoxicity tests for construction products are described in CEN/TR 17105.

(1) This document specifies an up-flow percolation test (PT) which is applicable to determine the leaching behaviour of inorganic and non-volatile organic substances from granular construction products. The test is not suitable for substances that are volatile under ambient conditions. The construction products are subjected to percolation with water as a function of liquid to solid ratio under specified percolation conditions. The method is a once-through column leaching test.
(2) This up-flow percolation test is performed under specified test conditions for construction products and does not necessarily produce results that mimic specific intended use conditions. This test method produces eluates, which can subsequently be characterized by physical, chemical and ecotoxicological methods according to existing standard methods. The results of eluate analysis are presented as a function of the liquid/solid ratio. The test results enable the distinction between different leaching behaviour.
NOTE 1   Volatile organic substances include the low molecular weight substances in mixtures such as mineral oil.
NOTE 2   It is not always possible to adjust test conditions simultaneously for inorganic and organic substances. Test conditions can also vary between different groups of organic substances. Test conditions for organic substances are generally more stringent than those for inorganic substances. The test conditions are generally described in a way that they fit testing organic substances and are also applicable to inorganic substances depending on the set-up.
NOTE 3   For ecotoxicity testing, eluates representing the release of both inorganic and organic substances are needed. In this document, ecotoxicological testing is meant to include also genotoxicological testing.
NOTE 4   Construction products with a low hydraulic conductivity that can cause detrimental pressure build-up are not supposed to be subjected to this test.
NOTE 5   This procedure is generally not applicable to products that are easily biologically degradable and products reacting with the leachant, leading, for example, to excessive gas emission or excessive heat release, impermeable hydraulically bound products or products that swell in contact with water.
(3) In this document the same test conditions as for prEN 17516 (CEN/TC 444/WG 1) are applied in order to allow full comparability of testing construction products and waste derived construction products to avoid double testing. The prEN 17516 test results are eligible in the context of testing construction products as well.
NOTE 6   If a leaching test according to prEN 17516 has been performed, additional prEN 16637 3 testing does not need to be carried out.

(1) This document allows the identification of the appropriate leaching test method for the determination of the release of RDS from construction products into soil, surface water and groundwater. This document provides a stepwise procedure for the determination of appropriate release tests, including:
a)   determination of the test method based on general product properties;
b)   choice of the test method using specific product properties.
(2) Furthermore, this document gives general guidance for CEN Technical Product Committees and EOTA WGs on basic aspects (sampling, sample preparation and storage, eluate treatment, analysis of eluates and documentation) to be specified in the relevant product standards or ETAs.
(3) Metallic products and coatings on metallic products are not considered in the determination scheme of this document since the test methods in prEN 16637 2:—1) (tank test) and prEN 16637 3:—2) (column test) are not appropriate for the testing of these construction products due to a different release mechanism (solubility control).
NOTE   See Annex F.
(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 [7]) 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 document since the test method in prEN 16637 2 is not appropriate for the testing of these construction products (in this case EN 16105 [8] might be an alternative method).

This document specifies a dynamic surface leaching test (DSLT) which is aimed at determining the release per unit surface area as a function of time of inorganic and/or non-volatile organic substances from a monolithic, plate- or sheet-like product, when it is put into contact with an aqueous solution (leachant). The test method is not suitable for substances that are volatile under ambient conditions.
This test is a parameter specific test focusing on identifying and specifying parameter specific properties tested under specified conditions. It is not aimed at simulating real situations. The application of results to specific intended conditions of use can be established by means of modelling (not included in this document).
The test method applies to more or less regularly shaped test portions consisting of monolithic test pieces with minimum dimensions of 40 mm in all directions [volume > 64 000 mm3 (64 cm3)]. It also applies to plate- or sheet-like products with surface areas of minimum 10 000 mm2 (100 cm2) exposed to the leachant. Products designed to drain water (e.g. draining tiles, porous asphalt) and monolithic granular products according to EN 16637 1:2023, Table 1, are also tested by this test method. All products to be tested are assumed to maintain their integrity over a time frame relevant for the considered intended use.
The modification for granular construction products with low hydraulic conductivity (Annex A) applies for granular particles with so little drainage capacity between the grains that percolation in percolation tests and in practice is nearly impossible.
Metals, metallic coatings and organic coatings on metals are excluded from the scope of this document because the principles of this test (diffusion) are not obeyed by these products. Guidance on the need for testing of these products is under consideration.
For some coatings (e.g. some renders with organic binders according to EN 15824 [9]) in intermittent contact with water, physical and chemical properties might be changed in permanent contact with water. For these products, this document is not appropriate.
Guidance on the applicability of the test method to a given product is outlined in EN 16637 1.
NOTE 1   This test method is only applicable if the product is chemically stable and the matrix does not dissolve. For construction products that are possibly used in contact with water this is usually the case as construction products are then supposed to be dimensionally stable. If a product possibly wears substantially in its intended use, the test cannot provide proper information. If the product contains a substantial amount of water-soluble compounds, e.g. gypsum or anhydrite, the matrix could (partially) dissolve and lead to dimensional instability of the test piece. In this case, the test standard also cannot be used.
NOTE 2   It is not always possible to optimize test conditions simultaneously for inorganic and organic substances. Optimum test conditions can also vary between different groups of organic substances. Test requirements for organic substances are generally more stringent than those for inorganic substances. The test conditions suitable for measuring the release of organic substances will generally also be applicable to inorganic substances.

This Technical Report gives information on existing methods to test ecotoxicity of construction products. Information is given on how to combine recommended leaching tests with biological tests for the aquatic environment and how to avoid possible problems, when performing biological tests. Also suitable terrestrial tests on granular construction products diluted with artificial soil are proposed for a minimum test battery.
Reference has been made as far as possible to existing International and European Standards and guidelines.
The test procedure described in this Technical Report is technically suitable for all construction product eluates and for terrestrial tests on granular or paste-like construction products. However, from the point of view of test efficiency it is recommended mainly for products containing organics or polymers in case chemical analysis alone is not deemed to be sufficient. For inorganic products the chemical analysis is seen as straightforward in construction product eluates and therefore the added value of data received through ecotoxicity tests is seen as limited.

(1) This document allows the identification of the appropriate leaching test method for the determination of the release of RDS from construction products into soil, surface water and groundwater. This document provides a stepwise procedure for the determination of appropriate release tests, including:
a) determination of the test method based on general product properties;
b) choice of the test method using specific product properties.
(2) Furthermore, this Technical Specification gives general guidance for CEN Technical Product Committees and EOTA WGs on basic aspects (sampling, sample preparation and storage, eluate treatment, analysis of eluates and documentation) to be specified in the relevant product standards or ETAs.
(3) Metallic products and coatings on metallic products are not considered in the determination scheme of this Technical Specification since the test methods in CEN/TS 16637-2 (tank test) and CEN/TS 16637-3 (column test) are not appropriate for the testing of these construction products due to a different release mechanism (solubility control).
NOTE See Annex F.
(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 [4]) 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 (in this case EN 16105 [5] might be an alternative method).

(1)   This Technical Specification specifies an Up-flow Percolation Test (PT) which is applicable to determine the leaching behaviour of inorganic and non-volatile organic substances from granular construction products. The test is not suitable for substances that are volatile under ambient conditions. The construction products are subjected to percolation with water as a function of liquid to solid ratio under specified percolation conditions. The method is a once-through column leaching test.
(2)   This up-flow percolation test is performed under specified test conditions for construction products and does not necessarily produce results that mimic specific intended use conditions. This test method produces eluates, which can subsequently be characterized by physical, chemical and ecotoxicological methods according to existing standard methods. The results of eluate analysis are presented as a function of the liquid/solid ratio. The test results enable the distinction between different leaching behaviour.
NOTE 1   Volatile organic substances include the low molecular weight substances in mixtures such as mineral oil.
NOTE 2   It is not always possible to adjust test conditions simultaneously for inorganic and organic substances and test conditions may also vary between different groups of organic substances. Test conditions for organic substances are generally more stringent than those for inorganic substances. The test conditions are generally described in a way that they fit testing organic substances and are also applicable to inorganic substances depending on the set-up.
NOTE 3   For ecotoxicity testing, eluates representing the release of both inorganic and organic substances are needed. In this document, ecotoxicological testing is meant to include also genotoxicological testing.
Construction products that exhibit a saturated hydraulic conductivity of about 10−8 m/s or higher can usually be subjected to this test. This procedure is also applicable to materials showing solidification in the column, if the final hydraulic conductivity is within the specified range. Inert granular material should not be added to improve permeability in order to enable their testing.
NOTE 4   This procedure is generally not applicable to products that are easily biologically degradable and products reacting with the leachant, leading, for example, to excessive gas emission or excessive heat release, impermeable hydraulically bound products or products that swell in contact with water.

(1) This Technical Specification specifies a Dynamic Surface Leaching Test (DSLT) which is aimed at determining the release per unit surface area as a function of time of inorganic and/or non-volatile organic substances from a monolithic, plate- or sheet-like product, when it is put into contact with an aqueous solution (leachant). The test method is not suitable for substances that are volatile under ambient conditions.
(2) This test is a parameter specific test focusing on identifying and specifying parameter specific properties tested under specified conditions. It is not aimed at simulating real situations. The application of results to specific intended conditions of use may be established by means of modelling (not included in this Technical Specification).
(3) The modification for granular construction products with low hydraulic conductivity (Annex A) applies for granular particles with so little drainage capacity between the grains that percolation in percolation tests and in practice is nearly impossible.
(4) The test method applies to more or less regularly shaped test portions consisting of monolithic test pieces with minimum dimensions of 40 mm in all directions (volume > 64 000 mm3 (64 cm3)). It also applies to plate- or sheet-like products with surface areas of minimum 10 000 mm2 (100 cm2) exposed to the leachant. Products designed to drain water (e.g. draining tiles, porous asphalt) and monolithic granular products according to CEN/TS 16637-1:2014, Table 1, are also tested by this test method. All products to be tested are assumed to maintain their integrity over a time frame relevant for the considered intended use.
(5) Metals, metallic coatings and organic coatings on metals are excluded from the scope of CEN/TS 16637-2 because the principles of this test (diffusion) are not obeyed by these products. Guidance on the need for testing of these products is under consideration.
(6) 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 changed in permanent contact with water. For these products CEN/TS 16637-2 is not appropriate.
(7) Guidance on the applicability of the test method to a given product is outlined in CEN/TS 16637-1.
NOTE 1   This test method is only applicable if the product is chemically stable and the matrix does not dissolve. For construction products that may be used in contact with water this usually should not be the case as construction products should then be dimensionally stable. If a product may substantially wear in its intended use, the test cannot provide proper information. If the product contains a substantial amount of water-soluble compounds, e.g. gypsum or anhydrite, the matrix may (partially) dissolve and lead to dimensional instability of the test piece. In this case the test standard also cannot be used.
NOTE 2   Volatile organic substances include the low molecular weight substances in mixtures such as mineral oil.
NOTE 3   It is not always possible to optimise test conditions simultaneously for inorganic and organic substances and optimum test conditions may also vary between different groups of organic substances. Test requirements for organic substances are generally more stringent than those for inorganic substances. The test conditions suitable for measuring the release of organic substances will generally also be applicable to inorganic substances.

(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:
a)   guidance for the identification of construction products potentially emitting Regulated Dangerous Substances;
b)   determination of the test method based on general product properties;
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.