BS EN 273:1992 pdf free download.Wood preservatives Determination of the curative action against Lyctus brunneus.
Introduction
BS EN 273 describes a laboratory method of test which gives a basis for the assessment of the curative action of a wood preservative against Lycs brunneus. It allows determination of the lethal effect of a surface application of the preservative on a population of larvae already established in the test specimens following egg-laying by adult beetles.
The method simulates conditions in practice when treating a timber component which has been attacked but is free from exit holes. In practice not all surfaces will be accessible to treatment.
The species Ltus brunneus is chosen because of its particular practical relevance and because it can be used easily in laboratory tests. The method can be used with other lyctid species, but the results may not be comparable with those obtained with Lycttis brunneus.
The test specimens are enriched with a defined nutrient solution, before exposure to egg-laying, in order to ensure uniformity of nutrient quality of test specimens between different laboratories.
This laboratory method provides one criterion by which the value of a curative preservative can be assessed. In making this assessment, the methods by which the preservative may be applied in practice should be taken into account. It is further recommended that the 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
BS EN 273 specifies a method for the determination of the curative action of a wood preservative agsinst Infestation by Ltus brunneus (Stephens).
This method is applicable to:
– organic formulations, as supplied or as
prepared in the laboratory from concentrates; or
– organic water-dispersible formulations, as
supplied or as prepared in the laboratory from
concentrates; or
– water-soluble materials, for example, salts.
5.2 Products and reagents
5.2.1 Paraffin wax, for sealing the relevant surfaces of specimens to be treated with solutions in which water Is the continuous phase.
NOrE. Paraffln wax with a setting point of 52°C to 54°C has been found suitable.
5.2.2 Gelatin, for sealing the relevant surfaces of specimens to be treated with solutions In which an organic solvent Is the continuous phase.
5.2.3 Rzste, for securing filter paper. The paste shall be starch-free, non-toxic to Ltiis and insoluble in the product under test.
N(Y1’E. Sodium carboxy methyl ceUuloee, food grade, has been found suitable.
5.2.4 Water, complying with grade 3 of ISO 3696.
5.2.5 So1ven or diluent, a volatile liquid that will dissolve or dilute the preservative but does not leave a residue in the wood at the end of the post-treatment conditioning period that has a toxic effect on the insects.
CAUTION Do not use benzene or other solvents which pose a health risk.
5.2.6 Peptone, prepared as an enzymatic hydrolysate of meat.
5.2.7 D (+)-glucose.
5.2.8 Filter paper or fine cloth, The fine cloth shall be of cotton or linen, with a mesh aperture of less than 0,3 mm.
5.3 Apparatus
5.3.1 Culturing chamber, with air circulation, controlled at (26 ± 1) °C, and at relative humidity (75±5)%.
5.3.2 Conditioning chamber well ventilated, controlled at (20 ± 2) °C and relative humidity (65±5)%.
NOFE, The conditioning of specimens may be carried out In the laboratory work area (see 5.3.4) provided that this has the conditions specified for the conditioning chamber (see 5.8.2).
5.3.3 Drying chamber, well ventilated, controlled at (30 ± 2) °C
5.3.4 Laboratory work area, well ventilated, where treatment of the test specimens Is carried out.
CAUTION It is essential to follow safety procedures for handling flammable and toxic materials. Avoid excessive exposure of operators to solvents or their vapours.
5.3.5 Testing chamber, with conditions identical to those of the culturing chamber (see 5.3.1).
8.3.1.1 For tests with solutions in which water is the continuous phase, apply three coats of paraffin wax (5.2.1) at about 90 °C so that the first coat adheres closely to the wood and the successive coat1n bond to one another. Condition the sealed specimens in the conditioning chamber (5.3.2) for at least one day.
8.3.1.2 For tests with preservative solutions in which the continuous phase Is an organic solvent that dissolves paraffin wax, use the gelatin (5.2.2):
apply the first coat with an aqueous solution at 200 g/l at 40 °C, then after a mrnirnum of 8 h of drying, apply two further coats of an aqueous solution of 300 g/l at 50 °C. Condition the sealed specimens in the conditioning chamber (5.3.2) for at least one day.
8.3.2 Treatment of test specimens
8.3.2.1 Preparation of treatment solution
8.3.2.1.1 Solid preservatives – water-soluble preservatives
Dissolve the preservative in the water (5.2.4) to the required concentration.
8.3.2. 1.2 LiqUid preservatives
If appropriate, use the preservative without further preparation other than any necessary stirring. If it is a concentrate, dilute it with the diluent to the required working concentration, using the procedure specified by the manufacturer.
All treatment solutions shall be freshly prepared.
8.3.2.2 Applitxztion qf the treatment solution Determine the actual area of each unsealed surface to be treated taking into account any possible encroachment of the sealing compound.
N(YFE 1. The total area to be treated is theoretically 35 cm2.
Determine the volumes or masses of the treatment solution (8.3.2.1) to be applied to each unsealed face to give the application rate specified by the supplier.
N(YF’E 2. The quantity of treatment solution to be applied should be realistic In view of the field of application and the manufacturer’s Instructions. Normally the quantIty will be 150 g’m2, but It should not exceed 200 g/m
In the laboratory work area (5.3.4), using either the pipette (5.3.9) or a brush, apply the calculated volume or mass of the treatment solution (8.3.2.1) to each of the unsealed faces as uniformly as possible. Apply the treatment solution to each unsealed face whilst keeping that face in a horizontal and upward facing position. Allow any surface liquid to be absorbed into each face before treating the next face.
N(YFE 3. If the required quantity cannot be applied In one application, the treatment solution may be applied In successive applications at appropriately close Intervals so as to avoid solidification of any substances hindering the penetration of the subsequent applications.
m) the results of the examination of the treated specimens and control test specimens:
– number of adult beetles emerged from the
wood,
– number of exit holes in the sealed arid
unsealed surfaces respectively,
– number of beetles found, dividing them into:
• living (i) adult beetles, (ii) larvae and (iii)
pupae
• dead (I) adult beetles, (ii) larvae and (Iii)
pupae;
n) the name of the organization responsible for the test report and the date of completion of the test;
o) the name and signature of officer(s) In charge of testing;
p) 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 also list any variation from the described test method as well as any factors that may have influenced the results.