Overview
EN ISO 19396-1:2025 - "Paints and varnishes - Determination of pH value - Part 1: pH sensors with glass membrane" (ISO 19396-1:2025) is a CEN-adopted laboratory method for measuring the pH value of polymer dispersions and coating materials using glass membrane pH sensors. Published July 2025 and replacing earlier editions, this standard clarifies terminology (changing “pH electrode” to pH sensor), calibration requirements and normative references to support consistent, traceable pH measurement across paints and varnishes testing laboratories.
Key topics
- Scope and principle: Specifies laboratory measurement principles for aqueous coating systems and polymer dispersions using potentiometric pH measuring chains with a glass membrane.
- Apparatus and materials: Details required equipment such as pH measuring apparatus, pH meter, glass-membrane pH sensors, temperature sensors, buffer solutions and storage solutions for sensors.
- Sampling and sample preparation: References ISO sampling and sample preparation protocols to ensure representative, reproducible results.
- Calibration and procedure: Defines calibration steps using buffer solutions, test conditions, number of determinations and stepwise measurement procedures for robust pH determination.
- Evaluation and reporting: Covers data evaluation, required contents of the test report, and handling of measurement stability.
- Precision: Presents precision information including repeatability (r) and reproducibility (R) limits derived from interlaboratory studies.
- Informative annexes: Annex A recommends pH sensors for different coating groups; Annex B explains determination of precision.
Applications
EN ISO 19396-1:2025 is intended for:
- Quality control laboratories in paint and varnish manufacturing for formulation control and batch release.
- R&D teams assessing formulation stability, shelf life and compatibility of polymer dispersions and coating systems.
- External testing laboratories providing accredited pH measurement services.
- Regulatory and conformity assessment activities where documented, standardized pH measurement is required.
Practical benefits include improved comparability of pH data, better sensor selection guidance, and clearer calibration practices for glass membrane pH measurement in coatings.
Related standards
Keywords: EN ISO 19396-1:2025, paints and varnishes, pH measurement, glass membrane pH sensor, polymer dispersions, coating materials, laboratory method, pH value determination.
