BS EN 49-1:1992 download.Wood preservatives Determination of the protective effectiveness against Anobium punctatum (De Geer) by egg-laying and larval survival
Part 1: Application by surface treatment (laboratory method).
Introduction
This Part of EN 49 describes a laboratory method of test which gives a basis for assessment of the effectiveness of a wood preservative, when applied as a surface treatment, against Anobium punctatum. It allows the determination of the concentration at which the product prevents the development of infestation from egg laying. It can also be used with formulations ready for use.
The method simulates conditions which can occur in practice on timber which has been treated some time previously with wood preservative applied by dip. brush or spray and on which eggs of Anobiurn punctatum are laid.
This laboratory method provides one criterion by which the value of a product can be assessed. In making this assessment the methods by which the preservative may be applied should be taken into account. It is further recommended that results from this test should be supplemented by those from other appropriate tests, and above all by comparison with practical experience.
When products which are very active at low concentrations are used it is very important to take suitable precautions to isolate and separate, as far as possible, operations involving chemical products, other products, treated wood, laboratory apparatus and clothing. Suitable precautions should include the use of separate rooms, areas within rooms, extraction facilities, conditioning chambers and special training for personnel.
1 Scope
This Part of EN 49 specifies a method for the determination of the protective effectiveness or the toxic values of a wood preservative against infestation by Anobium puncicitum (De Geer) when the product is applied as a surface treatment to wood.
This method is applicable to:
— water-insoluble chemicals which are being
studied as active insecticides, or,
— organic formulations, as supplied or as
prepared in the laboratory by dilution of
concentrates, or;
— organic water-dispersible formulations as
supplied or as prepared in the laboratory by
dilution of concentrates, or,
— water-soluble materials, for example salts.
NOTE This method may be used in conjunction with an ageing procedure, for example EN 73.
7.2 Quality of wood
Use only sound sapwood, straight-grained and without knots and bark2.
The growth rate shall be between 2 annual growth rings per 10 mm and 10 annual growth rings per 10 mm.
NOTE It is recommended to use test specimens of similar growth rate within a single test.
Take the test specimens from trees felled preferably in winter. They shall be cut immediately after felling and rapidly air-dried. The wood shall have been neither floated nor subjected to chemical or heat treatment. It shall not have been stored for more than three years.
7.3 Provision of test specimen
Cut the test specimens from planed strips having a cross section 25 mm x 15 mm with the larger longitudinal faces tangentially oriented. The transverse faces shall be cut neatly and have sharp edges. Take the specimens required for one test at random from a batch of specimens originating from at least three trees.
7.4 Dimensions of test specimens
The dimensions of each specimen after two weeks in the conditioning chamber (5.3.2) shall be:
(50±0,5) mm x(25±0,5)mm x(15±0,5)mm
NOTE The surface area of each test specimen excluding transverse faces 18 theoretically 40 cm2.
Mark each specimen so that it can be identified throughout the test.
7.5 Number of test specimens
Use:
a) for each preservative and each concentration:
five specimens (see 7.4);
b) for a complete test of any given preservative:
five untreated control specimens (see 7.4);
c) if a solvent or diluent (water included) is used:
five control specimens (7.4) treated with that solvent or diluent (5.2.4 or 5.2.5).
When dipping is to be used (8.1.3.2.1) it is advisable to treat more than the specified number of test specimens so that, after weighing, any specimens with abnormally high or low retentions can be rejected from the batch.
Place each specimen in one of the test containers (5.3.8) and add five female insects and at least five male insects. Cover the container with a disc of filter paper (5.2.6). Keep this in place with the cover.
8.3 Conditions and duration of the test Place the containers containing the test specimens and the insects in the testing chamber (5.3.5) for approximately one week. Count the eggs on each test specimen and, if there are fewer than 50, add another group of insects to the container and count the eggs again at the end of a further week in the testing chamber (5.3.5).
NOTE 1 Each control test specimen should have at least 50 eggs for the test to be valid.
NOTE 2 It may be necessary to add further insects in order to obtain an adequate number of eggs on all the specimens. However, premature mortality of the insects on the treatment test specimens alone may be due to the action of the preservative.
When premature mortality of the insects occurs, this shall be mentioned in the test report. If 50 eggs have not been laid on treated specimens after four groups of five pairs of insects have been added, continue without adding further insects and note this in the test report. When, at the end of several weeks, all the insects are dead, they shall be removed and the Lest specimens left in the containers in the testing chamber (5.3.5). Examine the test specimens 26 weeks after removal of the dead insects.
8.4 Examination of the test specimens After the 26 week period, count as accurately as possible the number of eggs laid on each test specimen and the number of eggs hatched4. Cut up all the specimens, count the larvae, noting their general condition.
NOTE Evaluation of the presence and size of larvae in the test specimens may be carried out at intervals during the test using the X-ray apparatus (5.3.10). if available.
9 Validity of test
The results shall be accepted as valid provided that the following conditions are met:
a) for each set of control specimens, a total of more than 50 live larvae are recovered; and b) live larvae are present in all control specimens.
10 Expression of results
10.1 Assessment of the protective effectiveness The protective effectiveness shall be expressed in terms of:
a) number of eggs laid on each specimen;
b) number of eggs hatched on each specimen: and
p) the name of the organization responsible for the test report and the date of completion of the test;
q) the name and signature of the officer(s) in charge of testing;
r) the following note:
“the interpretation and the practical conclusions that can be drawn from this test report demand a specialized knowledge of the subject of wood preservation and, for this reason, this test report cannot of itself constitute an approval certificate”.
The test report shall list any variation from the described test method and any factors that may have influenced the results.
It may include any optional observations made, for example X-ray examination (8.4).