SIST EN ISO 182-3:2026 PDF

Overview

EN ISO 182-3:2025 - Plastics: Determination of the tendency of compounds and products based on vinyl chloride homopolymers and copolymers to evolve hydrogen chloride and any other acidic products at elevated temperatures - Part 3: Conductometric method. Published Oct 2025 and adopted by CEN, this standard specifies a conductometric test to assess the thermal stability of PVC materials that undergo dehydrochlorination (release of HCl) when heated. The method is intended for characterizing the effectiveness of heat‑stabilizing systems in compounded PVC products and for cases where visual discolouration tests are inadequate.

Key topics and requirements

• Scope and applicability
  • Applicable to compounded PVC materials and products, including coloured compounds and a range of forms (plastisols, pellets, extrudates, mouldings, film, coatings, cable insulation) under agreed conditions.
  • Not applicable to dry blends (potential inhomogeneity) or to materials that release other decomposition products that alter water conductivity (in which case ISO 182-4 is referenced).
• Principle
  • Based on measuring the change in electrical conductivity of an absorbing solution as acidic vapours (primarily HCl) evolve from a heated PVC test portion.
• Test elements
  • Requirements cover reagents, apparatus, sample preparation, number of tests, temperatures for dehydrochlorination, test procedure, measurement cell setup, and expression of results.
• Quality and precision
  • Includes clauses on repeatability, reproducibility and comparison with the pH‑meter method (ISO 182-2), plus informative annexes on apparatus cleaning, statistical calculations and interlaboratory test data.

Applications and users

This standard is practical for:

• PVC compound formulators and additive suppliers evaluating heat‑stabilizer effectiveness.
• Quality control and testing laboratories performing routine thermal stability testing of PVC products.
• Manufacturers of cables, profiles, films, coatings and coloured PVC articles where color change tests are unsuitable.
• Materials engineers and regulatory bodies specifying thermal ageing or stability criteria in procurement and compliance documentation.

Using the conductometric method helps detect and quantify acidic evolution under controlled elevated temperatures, supporting formulation optimization, batch quality checks and material certification.

Related standards

• ISO 182 series - other parts cover alternate methods (e.g., ISO 182-2 pH‑meter method).
• ISO 182-4 - for determination of chloride ion (Cl−) in absorbing solutions when other decomposition products affect conductivity.

Keywords: EN ISO 182-3:2025, PVC thermal stability, conductometric method, dehydrochlorination, hydrogen chloride, plastics testing, heat‑stabilizers.