BS/EN 73-2014 pdf download.Wood preservatives Accelerated ageing of treated wood prior to biological testing Evaporative ageing procedure.
This BS/EN 73 specifies an evaporative ageing procedure, applicable to test specimens of wood which have been previously treated with a wood preservative, in order to evaluate any loss of effectiveness when these test specimens are subsequently subjected to biological tests.
2 Principle
Test specimens are prepared for biological testing of the effectiveness of wood preservatives against either fungi or insects using the appropriate standards methods. Test specimens are exposed, for a specified period. in a dust-free current of air of a defined velocity and temperature.
3 Equipment
3.1 A wind tunnel which is compartmented and fitted with devices for heating and distributing air.
The air shall be dust-free and shall not be polluted by chemical products which could have an effect on the test results.
The heating and distribution devices shall be such that the temperature and air velocity are maintained constant and uniform in each compartment.
The air leaving the tunnel shall be led away in such a manner that It cannot re-enter the tunnel.
3.2 A device which:
a) controls the temperature within the defined limits stated in 5.2;
b) measures and records the air temperature within the defined limits as stated in 5.2.
3.3 An anemometer capable of measuring air velocity of (1 i 0,3) ni/s.
4 Test specimens
4.1 Definitions and origin
The test specimens and their preparation are defined in the standards concerning the biological tests to which they are intended to be subjected.
The evaporative ageing procedure shall be carried out no more than 3 months after the end of the conditioning period that follows the treatment of the test specimens described in the relevant biological test standard. An alternative period can be used if specified by the product supplier This shall be stated in the test report.
4.2 Number of test specimens
The number of test specimens shall allow the relevant biological tests to be carried out in accordance with the instructions in the appropriate standards, bearing in mind that the evaporative ageing procedure shall be applied equally to treated test specimens that are subjected to biological agents and to control test specimens.
BS EN 73:2014
EN 73:2014 (E)
The control test specimens may be of the following kinds where required by the relevant test standard:
— treated control test specimens that will not be subjected to attack by biological agents after the evaporative ageing procedure. These will serve as controls for changes in mass in those tests in which this factor is taken into consideration;
— untreated control specimens which, after evaporative ageing, are subjected to the test by biological agents, to check any variation in the behaviour of untreated wood.
5 Procedure
5.1 Arrangement of the test specimens
Arrange the test specimens in the compartments on grids made from metal or any other inert material which can be decontaminated, resting them with one of their faces an the base so that none of the other faces is less than 10 mm from the side partitions. The faces parallel to the grain of the wood shall be parallel to the general direction of air flow and they shall be at least 10 mm from the corresponding faces of the adjacent test specimens. Do not place In the same compartment either test specimens treated with different products or with different concentrations or loadings of the same product or treated and control specimens. Arrange the test specimens according to type. as follows:
— Test specimens treated on all surfaces
Rest the test specimens on one of the small faces parallel to the grain of wood with the faces that are perpendicular to the grain of the wood at least 20 mm away from the corresponding faces of adjacent test pieces.
For example, specimens intended for testing in accordance with EN 113 (basidiomycetes).
— Test specimens for which the faces perpendicular to the grain of wood are sealed before treatment
Arrange the test specimens as above. The sealed faces may, however, be brought closer together.
For example, specimens intended for testing in accordance with EN 118 (termites).
— Test specimens with one treated face only
Rest the test specimens on the opposite face to that which has been treated.
For example, test specimens intended for the test determining preventive action against termites (EN 118)
and the larvae of Hylotrupes bajulus.
5.2 Starting and adjustment of the apparatus
With the test specimens in position, establish an air current controlled at a temperature of (40 ± 2) C which enters the compartments at a speed of (1 ± 0,3) mis.
5.3 Procedure
Maintain the test specimens in the arrangement specified in 5.1 and under the conditions specified in 5.2 for two weeks (14 days).BS/EN 73-2014 pdf download.
BS/EN 73-2014 pdf download
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