bsen927-2-20xx涂料和清漆木材外部的涂覆材料和涂覆系统第2部分性能规范

bsen927-2-20xx涂料和清漆木材外部的涂覆材料和涂覆系统第2部分性能规范内容摘要：

e optional evaluation of mould resistance. Performance criteria The scores for the assessment criteria, blistering, cracking, flaking and adhesion (from EN 9273) and the water absorption value (from EN 9275), are interpreted as meeting, or not meeting the required standard, relative to the enduse category, according to the criteria given in Table 1. These rankings are relative to the exposure conditions as described in . Interpretation of criteria: (1) The first four values in each column each represent the maximum allowed for the arithmetic mean (to one decimal place) of the three replicates from the natural weathering test (EN 9273). (2) The 39。 maximum sum value39。 is the limit which shall not be exceeded for the sum of the 12 (4  3) individual results. (3) The „maximum difference to qualify as valid test‟, refers to the difference between the highest and lowest score in any of the individual test panels. If this value is exceeded the test is declared invalid and shall be repeated. (4) The „water absorption value‟ is the maximum allowed for the arithmetic mean of the five replicates as determined by the procedure described in EN 9275. (5) If a coating system does not meet all of these profiles the manufacturer cannot claim full conformity in any of the three end use categories. Table 1 — Limit values for performance criteria Natural weathering and water absorption 39。 Stable39。 39。 Semistable39。 39。 Nonstable39。 Blistering 0,3 0,7 1 Cracking 0,7 1,7 3 Flaking 0,3 0,7 1,3 Adhesion 1 1 1 Maximum sum value 7 12 19 Maximum difference to qualify as valid test 2 3 4 EN 9275, water absorption value 175 g/m2 a  250 g/m2 a no limit a Nonmandatory values which will be revised/ratified in the light of ongoing work in CEN/TC 139/WG 2. NOTE Test precision An estimate of the standard deviation of the weathering test method was made in a large parative exercise carried out by members of the CEN Working Group. The findings of this exercise have been incorporated into the criteria matrix so that the underlying target values incorporate a tolerance to allow for variation in the performance of panel replicates. Attention has also been given to the expected distribution of results for a given test. Thus for example an arithmetic mean criterion of 1,3 for 39。 cracking39。 could be achieved as (1,1,2), (0,1,3) or (0,0,4). The „Maximum difference‟ criteria considers the probability of such scores occurring, and rules out those which are well outside the expected distribution. EN 9272:2020 (E) 7 Licensed copy: The University of Hong Kong, The University of Hong Kong, Version correct as of 25/03/2020 09 BSI Exposure conditions If the internal parison product (ICP – see EN 9273) meets the weathering criteria for the „stable‟ enduse category the exposure conditions are rated as 39。 medium39。 . If it does not meet these criteria the conditions are rated 39。 severe39。 (see EN 9271). Exposure conditions during the test are recorded in the „Expression of results‟ (Clause 6). Water permeability Water permeability shall be assessed in accordance with EN 9275 and expressed as a 39。 water absorption value39。 . The criteria for each enduse category are given in Table 1. 5 Optional tests The test methods listed in Table 2 are remended where additional information is required from the supplier of the coating system to meet specific enduser needs. They are not required for pliance with this European Standard, nevertheless when carried out they shall be reported in the format prescribed in Clause 6. Table 2 — Additional optional tests Test description Test method Blister box test any test method can be agreed, . BS 7956:2020, Annex C Blocking any test method can be agreed Stackability EN ISO 4622 Compatibility with glazing (sealing) pounds and profiles Overcoat following suppliers remendations Blue stain in service EN 1521 and EN 1522 Mould resistance value EN 9273 and Natural weathering with water trap EN 9273:2020, Annex F Natural weathering with alternative substrates EN 9273:2020, Annex F 6 Expression of results and interpretation Mandatory tests The ratings achieved in the weathering and permeability tests shall be reported and expressed according to the conventions listed in Table 3 or Table 4. Manufacturers claiming conformity with this European Standard for a specified coating system shall on request supply a data sheet containing the results in this format. Manufacturers may at their discretion expand the table format to include information from Table 5. EN 9272:2020 (E) 8 Licensed copy: The University of Hong Kong, The University of Hong Kong, Version correct as of 25/03/2020 09 BSI Table 3 — Mandatory tests for claiming full conformity Test description Reporting convention Appearance definition Build, hiding power and gloss in accordance with EN 9271 End use category or categories meeting full performance criteria „Stable‟ and/or „Semistable‟ and/or „Nonstable‟ Exposure conditions „Medium‟ or „‟severe in accordance with NOTE Some coating systems might meet more than one of the performance profiles. It is at the manufacturer39。 s discretion whether to claim conformity with more than one enduse category. Table 4 — Mandatory tests for claiming limited conformity Test description Reporting convention Appearance definition Build, hiding power and gloss in accordance with EN 9271 End use category or categories meeting limited performance criteria „Stable‟ and/or „Semistable‟ and/or „Nonstable‟ Substrate for which limited confo。