BS/EN 15425-2017 pdf download.Adhesives One component polyurethane (PUR) for loadbearing timber structures Classification and performance requirements.
When tested in accordance with 6.4 due to primer treatment of the wood surface, the average tensile strength of the untreated control samples shall not be lower than 2,0 N/mm2. The average tensile strength after cyclic treatment shall not be lower than 80 % of the average tensile strength of the untreated control samples.
5.5 Effect of wood shrinkage on the shear strength
When tested in accordance with 6.5, the average shear strength after climatic treatment shall not be lower than 1,5 N/mm2.
5.6 Static load test of multiple glue line specimens in compression shear
When tested in accordance with 6.6, not more than one of the six samples is allowed to fail during the test period. In each of the remaining test pieces, the mean creep deformation of all bond lines shall not exceed 0,05 mm after the test.
If a failure within a test piece occurs as a solid wood failure without any interference with the bond line, the test piece shall not be counted. In case more than two test pieces in a test series collapse due to solid wood failure (low wood quality), the whole test shall be repeated.
5.7 Creep deformation test at cyclic climate conditions with specimens loaded in bending shear
Adhesive type FInger jointing — maximum 0,1 mm glue line thickness in test (cc)
When tested in accordance with 6.7, the average ratio of the relative creep values of all five matched
bending specimen pairs evaluated after a given time t shall match the requirements in Table 5.
If the test fails to reach the given value after 26 weeks, the test may be continued for a second period of 26 weeks and a second assessment shall be performed after a total of 52 weeks under load. The load shall not be removed from the samples between the two test periods.
Adhesive type General purpose – 0,3 mm glue line thickness in test
When tested in accordance with 6.7, the average ratio of the relative creep values of all five matched bending specimen pairs evaluated after a given time t shall match the requirement in Table 5.
If the test fails to reach the given value after 13 weeks, the test may be continued for a second period of 13 weeks and a second assessment shall be performed after a total of 26 weeks under load.
If the adhesive also fail after 26 weeks, the test may continue and be assessed for the third time after a total period of 52 weeks. The load shall not be removed from the samples between the test periods.
Adhesive type Special purposes — 0,5 mm glue line thickness in test
The adhesive shall be tested in the same way and with the same duration times as for adhesive type
General purpose. The average ratio of the relative creep values of all five matched bending specimen
pairs evaluated after a given time t shall match the requirement in Table 5.
5.8 Long-term sustained load test at cyclic climate conditions with specimens loaded perpendicular to the glue line (“Glass house test”)
When tested according to 6.8, not more than one of the 10 loaded samples for each climatic period
(3 months, 6 months and 12 months) is allowed to fail during the test. The mean tensile strength
perpendicular to the glue line in each group of test pieces (control batch, 3 months, 6 months and
12 months) shall not be less than 5,0 N/mm2.
6 Test methods
6.1 General
The following test methods shall be used for establishing the requirements given in Clause 5. 6.2 Determination of longitudinal tensile shear strength
The test shall be made in accordance with EN 302-1 with a glue line thickness of close contact, 0,5 mm and 1,0 mm for application area Special purpose, close contact and 0,5 mm for application area General purpose and close contact and 0,3 mm for application area Finger jointing. Climatic treatments, as given in Table 3, shall he performed according to Annex A.
Test samples subjected to climatic treatment A6, A7 or A8 shall be wrapped before treatment to reduce moisture loss as much as possible. The samples shall be tested immediately after removal from the climate chamber in a testing machine supplied with a temperature-controlled chamber.
6.3 Determination of resistance to delamination
The test shall be made in accordance with EN 302-2.
6.4 Determination of tensile strength perpendicular to the glue line after climatic treatment (acid damaged test)
The test shall be made in accordance with EN 302-3 with primer- treated Norway spruce
(Picea abies L), and is mandatory if the pH value of the primer is lower than 3,0. The glue line thickness
shall be 0,5 mm for application area Special purpose and General purpose, and close contact (cc) for
Finger jointing.
6.5 Determination of the effect of wood shrinkage on the shear strength
The test shall be made in accordance with EN 302-4 with adhesives designed for the application areas Special purpose and General purpose.
6.6 Static load test of multiple glue line specimens in compression shear.BS/EN 15425-2017 pdf download.