BS EN 204 pdf free download

BS EN 204 pdf free download.Classification of thermoplastic wood adhesives for non-structural applications.
1 Scope This European Standard classifies thermoplastic resin based wood adhesives for non-structural applications into durability classes D1 to D4 based on the dry and wet strengths of bond-lines measured under specified conditions after various conditioning treatments. For special applications, further tests that do not fall within the scope of this standard may be applicable. The adhesives described in this standard are suitable for the bonding of furniture and interior structures, panelling, doors, windows, stairs etc made of wood or derived timber products. This standard does not define the temperature resistance of bond-lines NOTE Thermoplastic resin are described in EN 923 as: polymer or copolymer, capable of being softened by heating and hardened by cooling. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN 205 Test methods for wood adhesives for non-structural applications – – Determination of tensile shear strength of lap joints EN 923 Adhesives – – Terms and definitions3 Terms and definitions For the purposes of this European standard the terms and definitions given in EN 923 and the following definition apply. 3.1 thermoplastic wood adhesive adhesive whose main constituent is a thermoplastic resin and which has been formulated for bonding wood 4 Classification An adhesive shall be classified in accordance with Table 1, which gives examples of climatic conditions and fields of application in which the bonded member is to be used. The classification shall be based on tests on thin bond- lines except when gapfilling properties are claimed, in which case it shall be based on tests using both thin and thick bond-lines as defined in EN 205.5 Test method The adhesive shall be tested in accordance with EN 205 and as follows: a) either thin, or both thin and thick bond-lines shall be tested as appropriate (see clause 4); b) the tests shall be performed using the appropriate conditioning sequence given in Table 2; c) the individual values and the mean value for 10 valid test pieces for each conditioning sequence shall be recorded. The standard atmosphere used as a control climate is either (20+2)°C and (65+5)% relative humidity, (20/65), or (23+2)°C and (50+5)% relative humidity, (23/50). 6 Requirements When tested in accordance with EN 205 the mean strength of an adhesive shall: a) for thin bond-lines conform to the values shown in Table 2; b) for thick bond-lines, when required, be not lower than 80 % of the values shown in Table 2. NOTE The values given in Table 2 are comparative values and should not be used as a basis for calculation, e.g. of design data. They are not comparable with values obtained using test pieces of other dimensions.NOTE 1 A longer conditioning time between gluing and testing might be necessary as advised by the glue manufacturer. NOTE 2 The number used in the designation does not indicate ranking order. A given adhesive can be assigned to more than one durability class.BS EN 204  pdf download.