Overview
EN ISO 3071:2020 - Textiles: Determination of pH of aqueous extract (ISO 3071:2020) specifies a standardized laboratory method to measure the pH of the aqueous extract of textiles. It applies to textiles in any form (fibres, yarns, fabrics) and defines reagents, apparatus, specimen preparation, extraction and electrometric measurement using a glass electrode. The method is intended for consistent pH testing across quality control, regulatory and conformity-assessment activities.
Key topics and technical requirements
- Scope: pH measurement of an aqueous extract prepared from textile test specimens (applicable to all textile forms).
- Specimens: Cut representative sample pieces ~5 mm sides; take two test specimens of (2.00 ± 0.05) g each.
- Extracting solution: 0.1 mol/l potassium chloride (KCl) is specified as the extracting medium (water as extracting solution was omitted in this edition).
- Extraction procedure: Place specimen + 100 ml KCl solution in a stoppered flask; mechanically shake (reciprocating or rotational) for 2 h ± 5 min.
- pH measurement: Use a pH‑meter with glass electrode (resolution at least 0.01 pH units). Calibrate at the extract temperature using buffer solutions (recommended pH ~4, 7 and 9). Immerse electrode ≥10 mm; perform two measurements from two extracts and calculate mean.
- Reporting precision: Report the mean pH to the nearest 0.1 pH-unit. Interlaboratory reproducibility reported as R = 1.1 pH-units (using KCl extracting solution).
- Reagents & apparatus: Requires grade 3 distilled/deionized water (ISO 3696), KCl solution, standard buffer solutions (preparation described in Annex A), chemically resistant glassware, mechanical shaker, balance, volumetric flask.
- Test report content: Must reference ISO 3071:2020 and include mean pH, pH and temperature of the extracting solution, any factors affecting results (e.g., wetting resistance), and test date.
Practical applications
- Routine quality control of textile processing (dyeing, finishing) to detect residual acidity/alkalinity.
- Product safety and compliance where pH limits are specified by buyers, retailers or regulations.
- Troubleshooting manufacturing issues related to processing chemicals.
- Comparative testing in research, certification testing and supplier verification.
Who uses this standard
- Textile testing laboratories and QC departments
- Textile manufacturers, converters and finishers
- Certification and conformity-assessment bodies
- Textile chemists and R&D teams
Related standards
- ISO 3696 - Water for analytical laboratory use (reagent water quality)
- ISO 5725-2 - Precision of measurement methods (used for interlaboratory statistics)
- Annex A of ISO 3071:2020 - preparation of standard buffer solutions
This standard ensures consistent, reproducible measurement of textile extract pH, improving comparability across laboratories and supporting product quality and regulatory compliance.