Guidance on a semi-field test method for materials that are treated with biocides

Transcription

1 Final version 12 October 2015 Guidance on a semi-field test method for materials that are treated with biocides to fulfil requirements of the European Biocidal Products Regulation This guidance document describes a semi-field method for determining the leaching of active substances or other compounds from materials that contain biocidal products of main group 2 Preservatives according to the BPR [Regulation (EU) No 528/2012], i.e. Product-type 7 Product-type 9 Product-type 10 Film preservatives Fibre, leather, rubber and polymerised materials preservatives Construction material preservatives that are intended to be used under outdoor conditions out of ground contact and exposed to rain. This guidance was developed on the basis of CEN/TR 16663:2014: Durability of wood and wood-based products - Determination of emissions from preservative treated wood to the environment - Wooden commodities exposed in Use Class 3 (Not covered, not in contact with the ground) - Semi-field method and NT509 build: NORDTEST Method Leaching of active ingredients from preservative-treated timber Semi-field testing S The specifications of test conditions, sampling regime and chemical analysis of collected leachates for the materials considered in this guidance document are the same as in CEN/TR 16663:2014. Wood preservatives (product-type 8) are not considered in this guidance document since handling of treated wood is described in CEN/TR 16663:2014. This guidance applies to materials that are intended for large-area applications. Small-area application like sealants, or special application techniques require adopted procedures for the preparation of test specimens. Leachates may be collected and analysed as described in this document. Treated articles can contain active substances that originate from preservatives for products during storage (product-type 6). 1

2 Content 1 Description of the test method 2 Terms and Definitions 3 Equipment 4 Test setup 4.1 General 4.2 Sampling of test material 4.3 Preparation of test specimens Number and size of test specimens Preparation of test specimens from prefabricated treated articles Preparation of test specimens from treated articles to be applied to a substrate Substrate Preparation of substrate panels for test specimens Application of test material Conditioning 4.4 Preparation of test setups from test specimens 5 Test procedure 5.1 Exposure test site 5.2 Duration of the test 5.3 Collection of the leachates 5.4 Chemical analysis 6 Results 6.1. Results in concentrations 6.2. Results in terms of emissions 7 Test report Annex A (informative) Test setup and weathering rack Annex B (informative) Stability study Bibliography 2

3 1 Description of the test method Test setups of test materials are prepared and placed outdoors out of ground contact and exposed to weathering. The runoff from the test setups is retained and the leachate is monitored by chemical analyses of the target substances. Prior to testing customer and appointed laboratory have to clarify which active substances, relevant transformation products (e.g. metabolites) and other substances of concern according to the BPR 528/2012 (guidance in preparation) and additional physical-chemical parameters have to be analysed in the leachates. 2 Terms and Definitions For the purposes of this document, the following terms and definitions apply. analyte emission E leachate leaching prefabricated treated article test material release sampling period p substrate target substance test setup test specimen transformation product determinant, element, ion or substance to be determined by an analytical method; synonym for target substance liberation of chemical substances from a material, into soil, surface water or groundwater or into the leachant of a test facility The emission is expressed in units of released mass per surface area, i.e. milligrams per square metre. solution obtained by a field leaching test of a solid product in contact with rainwater release of inorganic and/or organic substances from a solid product by a leachant (in field studies it is rain) The leaching is expressed in units of released mass per surface area, i.e. milligrams per square metre. treated article that is produced and marketed in a way that it can be used as test specimen without further substrate used synonymously for treated article in this document synonym for emission period during which a (merged) leachate sample is collected material used as a base to apply treated articles in order to produce a test specimen substances (active substances, transformation products and/or substances of concern) to be tested test specimen with installations to be fixed on a weathering rack body that is tested for leachability of target substances, may be either a prefabricated treated article or a treated article applied to a substrate substance derived from the original substance, e.g. due to metabolism, hydrolytic or photolytic degradation 3

4 treated article weathering rack according to BPR 528/2012 Art. 3 (1l) any substance, mixture or article which has been treated with, or intentionally incorporates, one or more biocidal products installation to hold the test setups during outdoor exposure A coating material is a product, in liquid, paste or powder form, that, when applied to a substrate, forms a film possessing protective, decorative and/or other specific properties [EN ISO 4618:2006]; and a coating is a continuous layer formed from a single or multiple application of a coating material to a substrate. 3 Equipment 3.1 Preparation of test specimens Equipment suitable to cut panels or pieces from test materials and substrates. 3.2 Application of test materials (optional) Equipment suitable for carrying out vacuum, vacuum-pressure, immersion or surface treatment of specimens. 3.3 Balance A balance capable of weighing to the nearest 0.1 g. 3.4 Condition chamber Conditioning chamber, well ventilated, controlled at (22 ± 3) C and (60 ± 10) % relative humidity. 3.5 Preparation of test setups Devices (e.g. clamps) to attach the test specimens on the weathering rack. 3.6 Exposure site An open area, free from tall vegetation and not excessively influenced by industrial or agricultural pollution. 3.7 Weathering rack The weathering rack, to which the test setups are attached, should be robust to maintain the test setups in the required orientation for the duration of the test. Racks which have been found to be suitable are illustrated in Annex A. All construction materials used to fix and support the test setups (e.g. screws, hookes) and to collect the rainwater (gutter) shall be inert. Stainless steel has been found to be suitable (see Annex A). 4

5 3.8 Vessel for receiving water Leachates are collected in coated laboratory glass flasks that are protected from direct solar radiation or plastic jars with no impurities which can influence the target substances. Channelings have to be installed close to the test specimens. The receiving vessels are closed allowing only the incoming water from the weathering rack. S Laboratory brown glass flasks are preferred when the preservative contains organic biocides and plastic jars when the preservative contains inorganic biocides. Plastic jars cannot be used if the target substances are hydrophobic. It has to be verified that target compounds do not sorb to the plastic jar. EN ISO gives the good practices to preserve water samples. The brown glass flasks or plastic jars shall be protected from heat and sunlight. The capacity of the vessels depends on the exposure scenario. If the expected annual precipitation is approximately 700 mm and the test setup is placed horizontally 25 l containers are recommended. If the test setups are exposed vertically 5 l containers are recommended. Depending of the target substances, a preservative may have to be added to the vessels in order to prevent abiotic and/or biotic degradation. 3.9 Weather station A weather station capable of monitoring the temperature, quantity of rainfall, the wind direction and wind speed at the test site continuously shall be used. The kind of precipitation (rain, snow, hail) has to be noted Refrigerator/Freezer A refrigerator or freezer (-18 C or less) Chemical analysis equipment Analytical equipment appropriate to determine the target substance(s) in the leachate Safety equipment and protection clothing Appropriate for the test product, to ensure the safety of the operator. 4 Test setup 4.1 General Test setups are prepared from either test specimens from prefabricated test materials or test specimens prepared by application of a test material (e.g. a coating material) onto a substrate. The test specimens are representative or typical of commercial treated articles, and exposed to mimic service exposure. Alternatively the test specimens may be prepared to be a realistic worst case estimation of the emission for a treated article under outdoor exposure. 5

6 Test specimens of treated articles into which the biocides are usually brought by means of industrial processes (e.g. impregnation of textiles, treatment of fibres and plastics) have to be obtained as prefabricated treated articles from these procedures, and shall not be prepared by laboratories themselves. 4.2 Sampling of test material The sample of the test material shall be representative of the product to be tested. Samples shall be stored and handled in accordance with any written requirements from the supplier. The sampling and conditioning procedure should be recorded in a sampling report The product shall be analysed for the target substance(s) prior to use if possible. It has to be reported whether the original content of target substance(s) was confirmed or not. 4.3 Preparation of test specimens Number and size of test specimens Prepare 2 test specimens for each test or combination of test parameters. The minimum dimensions of the front face (vertical exposure) or top face (horizontal exposure) are (760 ± 5) mm in length and (760 ± 40) mm in width. Alternatively the pieces of treated articles can be prepared in a way typical of commercial practice. The actual dimensions shall be stated in the test report. Each test specimen shall be marked to identify it throughout the test. For treated articles that are usually applied on large vertically oriented areas, test results from larger test specimens (particularly in the vertical dimension) represent use conditions better than results from test specimens with the proposed dimensions. The defined dimensions can be considered as worst case situation concerning exposition to rain and amount of runoff per surface area Preparation of test specimens from prefabricated treated articles Test specimens with dimensions given under are cut from the prefabricated treated articles. It can be necessary to fix pieces of prefabricated treated articles (e.g. textiles) onto appropriate frames. 6

7 Lateral faces of porous or water absorbing materials are end-sealed by a material which prevents water entry and damage of the material. The end-sealer shall remain effective during long-term exposure to the weather and may not contain biocides or other target substances. Calculate the amount of active substance(s) for each test specimen and express the result in grams of active substance(s) per square metre of exposed surface area Preparation of test specimens from treated articles to be applied to a substrate Substrate The substrate used to carry the material shall have a homogeneous planar surface, shall be inert and test products shall adhere well to it during the outdoor exposure. As the substrate can influence the results, it shall be stated in the test report. S See examples for substrates in Annex A. Substrates might influence the leaching (e.g. concrete, mineral renders and fibre cement board and wood substrates). The test material has to be intended for the selected substrate, e.g. coatings have to be stable towards alkalinity if fibre cement is selected as substrate Preparation of substrate panels for test specimens Cut panels of the substrate with dimensions given under Application of test material Test materials have to be applied on substrates according to the manufacturers instruction. Apply the maximum amount if a range is given for the application of a coating material. The substrate shall be clean and dry. The substrate shall be coated with the test material in the specified quantity in accordance with the recommendations of the manufacturer. Determine and record the total mass applied. The test material is applied only to the exposed front face if the test specimen is intended to be installed vertically on the weathering rack. The test material is applied to the exposed top face and the lateral faces if the test specimen is intended to be installed horizontally on the weathering rack. In this case the surface areas of the lateral faces are included in the calculation of area-based emissions. Follow the supplier s instructions for applying surface coating or water-repellent treatment. 7

8 Lateral faces of porous or water absorbing materials substrate panels are end-sealed by a weatherproof material which prevents water entry and damage of test specimens if they are intended to be exposed vertically. The end-sealer shall remain effective during long-term exposure to the weather and may not contain biocides or other target substances. Calculate the amount of target substance(s) for each test specimen and express the result in grams of target substance per square metre of exposed surface area if appropriate. Reject any test specimen with amounts of test material deviating by more than 5 % from the average for that type of test specimen and substitute an appropriate alternative which falls within this range Conditioning Condition the test specimens with freely circulating air without UV influence and without exposure to rain for a period agreed with the manufacturer. S If no details are provided by the manufacturer the conditioning period should be 1-2 weeks. A process which has been found to be suitable is to dry the treated test specimens in a well-ventilated area protected from rain and frost and a maximum temperature of 30 C. Follow the supplier s instructions for applying surface coating or water-repellent treatment. Use an inert material as glass or stainless steel to support the test specimens. The test specimens may not touch each other. Note the period from treatment to installing the test setups to the weathering rack. 4.4 Preparation of test setups from test specimens Install devices (e.g. clamps) to attach the test setups on the weathering rack. 5 Test procedure 5.1 Exposure test site The test is valid using one test site; however, it may be advantageous to select more than one test site representing markedly different climatic conditions. Place the test setups on the weathering rack (see Annex A). The test setup can be exposed horizontally or vertically depending on the data required. The vertically exposed test setups shall be orientated to reflect the most severe weather conditions concerning wind, rain and sunlight. This has to be justified in the test report. 8

9 S It has to be assured that vertically exposed test specimens from the same experiment are exposed to the same amount of driving rain. Data required: if the intended use includes horizontal exposure, test data on horizontal exposure are required. The applicant is free to deliver additional emission data conducted by various orientations of the test racks. Recommendations on the installation of test specimens and descriptions of climatic conditions are given in DIN EN ISO 2810: Duration of the test The minimum duration of the assessment period is two years. A minimum number of 5 data points in the first year and a minimum number of 3 data points in the second year are required. S A mean annual precipitation for Europe of 700 mm is considered to be an optimum, but will not be reached at each site. The aim is to have sufficient data points to allow extrapolation in order to estimate long term leaching for the service life. It has to be justified if an experiment is finished earlier than the two years. 5.3 Collection of the leachates The leachate shall be sampled after each significant rain event or after the required sampling period. The time and the date are recorded. The sampling period should be increased to larger intervals but a short sampling period in the beginning is known to be suitable. Sampling periods can be increased depending on the duration of the test. The first sampling period shall not exceed 50 mm of precipitation. The amount of snow is given as the corresponding amount of water (determined for melted snow). Any signs of microbiological growth in the leachate or on the test specimens shall be recorded in the test report. Leachates from different rain events within a sampling period can be bulked. Samples of the leachate from the sampling periods may be stored (e.g. 1 l). S The frequency of leachate collection has to be decided by the laboratory depending on the volume of runoff samples, stability of target substances, anticipated weather conditions. 9

10 The amount of leachate can be large and it can be advantageous to store only a few percent of the leachate. The same percentage of leachate shall be sampled and stored after each rain event. Samples should be stored under conditions that preserve the compounds of interest, e.g. in a refrigerator or in a freezer in the dark to reduce degradation of the target substances and microbial growth in the sample before analysis (see Annex B). The storage procedure shall follow recommendations from the supplier of the product or EN ISO S Use available information or preliminary stability tests to decide on an appropriate storage method. Guidance on the preservation and handling of water samples is given in EN ISO These conditions have to be convenient with the nature (organic, inorganic compound) of the target substance(s). A maximum time of storage before the analysis should be defined. The leachate is stored in a freezer at a temperature below -18 C after, for example, acidification for inorganic compound or extraction for organics. 5.4 Chemical analysis Chemical analysis of the collected leachates is conducted after a planned time schedule, e.g. after increasing sampling periods. This is an example of a schedule: 0-20 mm, mm, mm, mm, mm, mm, mm, mm, mm and mm of rain. The validity of the analytical method for the target substances shall be determined before conducting the test: a) accuracy; b) specificity; c) limit of detection; d) limit of quantification; e) precision (See also Annex B) It has to be reported if the analysed substances are stable during storage of the runoff samples until chemical analysis. It has to be included in the test report if there are data on limited stability of analysed substances in water. 6 Results 6.1 Results in concentrations Express the analytical results as concentration c of each target substance analysed in the merged leachate for each sampling period in milligram per litre. 10

11 6.2. Results in terms of emissions Convert the analytical results c p for the leachates from the sampling periods expressed in milligram per litre to emissions E in milligram per square metre for each sampling period p (e.g mm, mm) with Equation (1) E p = c p Vp A where p E p A c p V p is the running number of the sampling period; is the emission during the sampling period p, in milligram per square metre; is the exposed surface area of the test specimen, in square metre; is the measured concentration of the target substance in the merged leachate of the sampling period p, in milligram per litre; is the real volume of the merged leachate after the sampling period p, in litre. The exposed surface area of the test specimen is defined as a) surface area of top face and lateral faces, e.g. (0.76 m 0.76 m + 4 (0.76 m width of lateral faces) = ( x) m². for horizontally exposed test specimens b) surface area of the front face, e.g. (0.76 m 0.76 m) = m² for vertically exposed test specimens.. Calculate the cumulative emission during the total time of the test according to Equation 2. Equation (2) E = n p=1 E p where E E p p n is the cumulative emission during the total time of the test, in milligram per square metre; is the emission during the sampling period, in milligram per square metre; is the running number of the sampling period is the number of the final sampling period Additional assessment shall be done, for example the percentage of leaching. 11

12 7 Test report The test report shall contain at least the following information: a) reference to this guidance document; b) specific and unique name or code of the treated article, the trade or common name of the active substance(s), substances of concern (as defined in the Regulation (EU) No 528/2012); c) all details necessary to identify the test material; d) name of the organisation responsible for the test report and the date of issue; e) name(s) and signature(s) of the persons responsible; f) date of order, the name and address of the sponsor of the test; g) results of chemical analysis of the biocides in the test material; h) conditioning and sampling of the test material; i) solvent or diluents used (if applied); j) material of the substrate for application of test materials*; k) number and dimensions of the test specimens; l) method and date of application of the test material*; m) individual and mean amount of test material on the substrate panels in grams or millilitres per square metre as appropriate*; n) method and drying time after application of the test material and details of post treatment*; o) method and duration of conditioning or storage of the test specimens; p) amount of target substances in the test specimens in milligrams per square metre exposed surface area; q) location (latitude, longitude and elevation) and detailed description of the exposure site(s) including information on temperature and rainfall (precipitation); r) date and installation of the test setups; s) date of collection of each leachate and the corresponding amount of rainfall for each sampling period in millimetres; t) duration of the sampling period(s); u) conditions of storage of the leachate prior to chemical analysis; v) analytical methods used to determine target substances in the merged eluates; w) time schedule for chemical analysis of the collected leachates. x) information on the stability of the analysed substances during storage of the eluates prior to analysis; y) leaching in milligram per square metre exposed material for the sampling periods; z) any deviations from this standard and any special factors which may have influenced the results. * information is not necessary when the test specimen is a prefabricated treated article It is recommended to add graphs that represent the cumulative emissions of each target substance in milligram per square metre versus the amount of rain in millimetres. 12

13 Annex A (informative) Test setup and weathering rack Figure A.1 Example for a test setup for vertical exposure (plan and sectional view) The width of the gutter and the distance between the gutter and the lower edge of the test specimen have to be optimised in a way that runoff cannot be lost at high wind speeds and test specimens cannot not dip into snow test set-up 2 stainless steel tray 3 laboratory glass flask to sample runoff Figure A.2 Example for a test setup for horizontal exposure (sectional view) Test specimens have to be installed slightly downgraded to ensure that water runs into the collecting container. 13

14 Examples of test setups and weather racks at a field test area Figure A.3 Vertically oriented test setups Figure A.4 Horizontally oriented test setup Examples for substrates Substrate XPS (extruded polystyrene) EPS (expanded polystyrene) weather-proof glued plywood solid wood fibre cement Treated article Coating materials, e.g. paints and renders Coating materials, e.g. paints and renders paints for wood paints for wood roof paints 14

15 Annex B (informative) Stability study Prepare a reference sample with defined amounts of target substances in water if possible. Water is spiked with the substances in question so that the concentration is in the range expected in the test. Alternatively, the first runoff sample can be spiked with target substances and used as reference sample. Store the reference sample under the same conditions as the runoff sample. Analyse the reference sample in parallel with the runoff samples from the experiment. Check and report the stability of the target sample. Limit of detection/quantification: The analytical method is developed and different calibration solutions (at different concentrations) are analysed. The quantification limit is chosen to be the concentration of the most diluted calibration solution which gives a good correlation. Recovery: A triplicate recovery experiment is performed at two levels: just above the quantification limit and at a concentration, which is expected to be close to maximum concentrations that will be found during the study. Bibliography Regulation (EU) No 528/2012 of the European Parliament and of the Council of 22 May 2012 concerning the making available on the market and use of biocidal products. Nordtest Standard NT Build 509: NORDTEST Method Leaching of active ingredients from preservative-treated timber Semi-field testing CEN/TR 16663:2014: Durability of wood and wood-based products - Determination of emissions from preservative treated wood to the environment - Wooden commodities exposed in Use Class 3 (Not covered, not in contact with the ground) - Semi-field method DIN EN ISO 2810:2004: Paints and varnishes. Natural weathering of coatings. Exposure and assessment (ISO 2810:2004) EN ISO :2003: Water quality Sampling, Part 3: Guidance on the preservation and handling of water samples 15