Cellulose-containing textiles are considered resistant to attack by micro-organisms present in soil if their structure, appearance and tensile strength are not essentially altered after a soil burial test. The resistance to deterioration is assessed by measuring the relative reduction in tensile strength between buried and unburied specimens.
If an assessment of long term resistance is required, the procedure described in ISO 11721-2 (in preparation) is applicable.
Due to the biological nature of the soil burial test, and the fact that the test soil cannot be precisely standardized, this standard is only intended to assess the resistance of a fabric to micro-organisms after comparing the performance of specimens with and without a finish.
This standard specifies a method for determination of the resistance of chemically-pretreated textiles to the action of micro-organisms present in soil in comparison with untreated textiles.
This method is applicable to flat textiles made of cellulosic-containing yarns (tentage, tarpaulins, webbing and tapes) that will typically come into contact with soil during use.
Due to the inherent resistance of most synthetic fibres to attack by micro-organisms, fabrics containing a high proportion of synthetic fibres can only be judged by these methods for changes in structure and appearance.
Although this method allows good reproducibility of results, it is intended to show comparative performance rather than provide absolute values.
NOTE Heavy tarpaulin fabrics and webbing may be of such a structure that samples without finish are resistant within a 14 days soil burial period. Also in such cases the decay rate of the untreated sample determines the length of the burial period.
2 Normative references
This International Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this International Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).
ISO 139, Textiles — Standard atmospheres for conditioning and testing
ISO 7218, Microbiology of food and animal feeding stuffs — General rules for microbiological examinations
ISO 8022, Surface active agents — Determination of wetting power by immersion
ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and elongation at maximum force using the strip method