BS EN 302-2-2004 pdf download.Adhesives for load-bearing timber structures — Test methods — Part 2: Determination of resistance to delamination.
After bonding and pressing, and before cutting and testing, condition the assembly for seven days in the standard atmosphere ((20 ± 2) °C and a relative humidity of (65 ± 5) %).
NOTE A longer conditioning time may be used If recommended by the adhesive manufacturer.
6.3 PreparatIon of the test pieces
Fron, a full cross-section of each of the four laminated members to be tested, cut two test pieces using a sharp saw or other tool that produces a smooth surface. Remove sections 75 mm long by cutting perpendicularly to the surface of the assembly and not less than 50 mm from either end of the member. Record the time elapsed between the preparation of the test pieces and testing.
6.4 Test procedures
6.4.1 General
Weigh and record the test pieces weight to the nearest gram. Place the test pieces in the pressure vessel and secure them to prevent them from floating. Add water at a temperature of (10 to 25) C to submerge completely the test pieces. Separate the test pieces by using at least 5 mm thick stickers, wire screens or other means in such a way that all end-grain surfaces are freely exposed to the water. Carry out either the high temperature procedure according to 6.4.2 for testing compliance with the requirements for type I adhesives for use in severe climatic conditions, or the low temperature procedure according to 6.4.3 for testing compliance with the requirements for type II adhesives for use in moderate climatic conditions.
6.4.2 High temperature procedure (for type I adhesives)
Reduce the pressure in the vessel to (25 ± 5) kPa absolute and maintain that pressure for 15 mm. Release the vacuum and apply a pressure of (600 ± 25) kPa absolute for one hour. With the test pieces still completely immersed, repeat this vacuum-pressure cycle once again to give a two-cycle impregnating period requiring a total of about 2 h 30 mm.
Dry the test pieces for 20 h In air let in at (65 ± 3) °C and a relative humidity of (10 to 15) % and circulating at a velocity of (2,25 ± 0,25) mIs. During drying, place the test pieces at least 50 mm apart with the end-grain surfaces parallel to the air stream.
After the elapsed drying period, control the mass of the test pieces on a weighing scale to the nearest gram. The end of an impregnating-drying cycle for any given test piece shall only be considered when the mass of the test piece is between 100 % and 110 % of the original mass (Om). Should the mass of any given test piece exceed its original mass (Om) by more than 10 % after the 20 h drying treatment has elapsed, place the test piece in the drying duct once again, and subject it to further identical drying conditions. Remove the test piece and re-weigh its mass after one hour. Repeat this process until the test piece Is within the required mass range. Record the mass of the test piece after every impregnating-drying cycle and record the total drying time needed to reach the required mass of the respective test piece. Should the mass of the test piece be lower than its original mass (Om) after the drying treatment, the test piece shall be rejected, and new test pieces shall be made and tested.
NOTE Test pieces may be removed and subjected to a weight inspection dunng the drying treatment before the 20 h have elapsed, so as to ensure that the test pieces are not over-dried.
Repeat the entire impregnating-drying cycle twice more, to comprise a total test period of just over three days.
6.4.3 Low temperature procedure (for type II adhesives)
Reduce the pressure in the vessel to (25 ± 5) kPa absolute and maintain that pressure for 15 mm. Release the vacuum and apply a pressure of (600 ± 25) kPa absolute for one hour. With the test pieces still completely immersed, repeat this vacuum-pressure cycle once more to give a two-cycle impregnating period requiring a total of 2 h 30mm.
Dry the test pieces for 90 h in air at (25 to 30) °C and (30 ± 5) % relative humidity, and circulating at a velocity of (2,25 ± 0,25) rn/s. During drying, place the test pieces at least 50 mm apart with the end-grain surfaces parallel to the air stream.
After the elapsed drying period, control the mass of the test pieces on a weighing scale to the nearest gram. The end of an impregnating-drying cycle for any given test piece shall only be considered when the mass of the test piece is between 100 % and 110 % of the original mass (Om). Should the mass of any given test piece exceed its original mass (Om) by more than 10 % after the 90 h drying treatment has elapsed, place the test piece in the drying duct again, and subject It to further identical drying conditions. Remove the test piece and re-weigh its mass after two hours. Repeat this process until the test piece is within the required mass range.BS EN 302-2-2004 pdf download.