ISO 11721-1:2001

Overview

ISO 11721-1:2001 - Textiles: Soil burial test (Part 1) specifies a laboratory method to assess the resistance of cellulose-containing textiles to micro-organisms in soil, with a focus on the assessment of rot-retardant finishing. The method is comparative: it measures the relative loss of tensile strength of finished versus unfinished specimens after controlled soil burial under conditions that promote microbial attack.

Key topics and technical requirements

• Test objective: Compare degradation of treated (rot‑retardant finished) and untreated cellulose-based fabrics after soil burial.
• Specimens: Cut from fabric (typically 300 mm × 30 mm, frayed to a 20 mm central width); 20 specimens per test (10 unburied controls, 10 buried), plus additional control specimens to determine burial duration.
• Soil preparation: Use commercial compost or compost-containing garden soil; soil must be fine-grained, pH 4.0–7.5 and adjusted to (60 ± 5) % of water‑holding capacity (WHC) for optimal microbial activity.
• Incubation conditions: Containers incubated at (29 ± 1) °C and 95–100% relative humidity; maintain soil moisture during the test.
• Duration and validation: Burial continues until untreated control specimens show approximately 80% reduction in tensile strength (time-trial must not exceed nine days for validation; different guidance for blended/synthetic fabrics).
• Leaching and pre‑treatment: Finished and unfinished specimens are normally leached under running water (24 h at ~20 °C) before testing unless otherwise agreed.
• Measurements: Tensile strength before and after burial (refer to ISO 13934-1 for tensile testing) and visual/microscopic inspection.
• Safety: Tests involve viable moulds/bacteria; follow microbiological safety and hygiene procedures (see ISO 7218).

Applications and who uses it

• Textile manufacturers and finish formulators evaluating rot‑retardant finishes for cellulosic products (e.g., tentage, tarpaulins, webbing, tapes).
• Independent textile test laboratories performing standardized durability and biodegradation comparisons.
• Quality assurance and R&D teams assessing lifecycle performance of natural‑fiber textiles exposed to soil or ground contact.
• Specifiers and procurement professionals who require evidence of microbial resistance for outdoor and ground-contact textile products.

Related standards

• ISO 11721 series: Part 2 (attack by micro‑organisms/mixed culture), Part 3 (toxicity of textile materials and finishing agents), Part 4 (saturated atmosphere test - mildew).
• Normative references cited: ISO 139, ISO 7218, ISO 8022, ISO 13934‑1.

This standard is intended for comparative assessment of rot‑retardant treatments rather than to provide absolute biodegradation values. Use ISO 11721‑1:2001 when you need a reproducible, laboratory‑controlled soil burial test for evaluating microbial resistance of cellulose‑containing textiles.