ISO 3998:1977 pdf download.Textiles - Determination of resistance to certain insect pests
1 SCOPE AND FIELD OF APPLICATION
This International Standard specifies a method for the determination of the resistance of textiles to the larvae of certain insects. It is applicable to all textiles containing animal fibre in any porportion. Information relating to the breeding of the larvae is given in the annex.
2 PRINCIPLE
Conditioned voracity control specimens and test specimens of known mass are placed in contact with selected larvae for 14 days. The loss in mass of all specimens, the extent of the attack on test specimens and the condition of the test larvae are ascertained to assess the resistance of each test specimen.
3 APPARATUS
3.1 Metal containers, the covers of which are pierced with ventilating holes, shallow, large enough to permit the test larvae to remain in contact with, or move away from, the test specimens. A suitable size is 45 mm diameter, 10 mm height.
5.1.1 Test specimens
Select at random eight test specimens from the sample of material to be tested, at widely spaced intervals. Use four of these as test specimens and four as moisture regain controls.
5.1.2 Test contro/ specimens
As it is essential to provide a control on the larval voracity,select eight test control specimens of undyed unproofed woollen material or yarn corresponding to the sample to be tested. Use four of these eight specimens as voracity controls and four as moisture regain controls.
NOTE一A test control specimen should be known to support insect growth and should preferably, but not necessarily, be of the same type of material as the test specimen. A test control specimen is used to check that the test has been done correctly and that the test larvae are viable.
6.2 Details of breeding of the above larvae are given in the annex. There may be variations in the life cycle due to dif-ferences among strains of the same species of insects or the type of rearing medium used, which may call for some deviation in the age of the larvae used for tests. In that case,the deviation should be indicated in the test report. Dif-ferences caused by Variation in temperature and humidity are largely overcome by use of the standard conditions given in clause 4.
7 PROCEDURE
7.1 Condition all sixteen specimens in the atmosphere specified in clause 4, for 24 h, then determine the mass of each separately in a stoppered weighing bottle (3.3) to an accuracy of 0,1 mg.
7.2 Place each of the specimens of known mass in a separate container (3.1). On to each of the four test speci-mens and the four voracity control specimens place fifteen larvae of the selected insect or pest.
7.3 Keep the sixteen containers in the dark, in the test atmosphere, for a period of 14 days.ISO 3998 pdf download.