Overview
ISO 1431-3:2017 specifies reference and alternative methods for determining ozone concentration in laboratory test chambers used for assessing the resistance of vulcanized or thermoplastic rubber to ozone cracking. It defines a UV absorption reference method and alternative instrumental and wet‑chemical techniques, including calibration and reporting requirements. The document is part of the ISO 1431 series on rubber resistance to ozone cracking.
Key technical topics and requirements
- Reference method (Method A - UV absorption)
- Adopted as the calibration reference for other methods.
- Carried out in accordance with ISO 13964 (air quality - ultraviolet photometric method).
- Alternative instrumental methods (Method B)
- B1 - Electrochemical: coulometric cell with buffered KI solution; current proportional to ozone concentration.
- B2 - Chemiluminescence: reaction of ozone with ethylene producing measurable light.
- Wet‑chemical methods (Method C)
- Procedures I, II and III (annexed normative descriptions) based on ozone absorption and titration techniques.
- Calibration and procedure
- All apparatus must be calibrated against the UV absorption method (ISO 13964).
- Instrument setup, zeroing and routine checks are required for reliable measurements.
- Expression of results
- Ozone concentration usually expressed in parts per hundred million by volume (pphm); alternatives include mg/m³ or mPa (partial pressure of O3).
- ISO 1431-3 provides conversion guidance and notes that at 1 013 hPa and 273 K, 1 pphm ≈ 1.01 mPa.
- Influence of atmospheric pressure
- Annex A (informative) explains how ambient pressure affects cracking rates and recommends expressing concentration as partial pressure or correcting volumetric values.
- Safety
- Ozone is highly toxic; the standard highlights recommended exposure control and ventilation (an absolute maximum of 10 pphm is suggested unless national rules are stricter).
Practical applications and users
- Test laboratories performing ozone cracking resistance tests on rubber products.
- Rubber manufacturers and quality control teams validating materials for outdoor or ozone-prone applications (hoses, seals, tyres, gaskets).
- R&D groups comparing sensor technologies (UV, electrochemical, chemiluminescence, wet chemistry).
- Standards bodies and accreditation organizations verifying measurement traceability and calibration procedures.
Related standards
- ISO 1431-1 - Rubber - Resistance to ozone cracking - Part 1: Static and dynamic strain testing (test methods).
- ISO 13964 - Air quality - Determination of ozone in ambient air - Ultraviolet photometric method (reference method for calibration).
Keywords: ISO 1431-3:2017, ozone concentration, UV absorption, electrochemical ozone sensor, chemiluminescence, wet‑chemical ozone analysis, rubber ozone cracking, laboratory test chambers, ISO 13964, calibration, ozone measurement.
Open preview (PDF)Rubber, vulcanized or thermoplastic — Resistance to ozone cracking — Part 3: Reference and alternative methods for determining the ozone concentration in laboratory test chambers