Overview
ISO 11114-3:2010 specifies an autogenous ignition test for determining the ignition behavior of non‑metallic materials in pressurized gaseous oxygen. The standard defines how to measure the autogenous ignition temperature - the temperature at which a sudden, self‑sustaining increase in temperature and pressure occurs - and provides test procedures, apparatus guidance and reporting requirements. ISO 11114-3 is intended to help rank and select materials for oxygen compatibility in gas cylinders, valves and accessories, and to support type testing requirements (for example ISO 10297 for cylinder valves).
Key topics and technical requirements
- Test principle: heat a small quantity of test material in a sealed reaction chamber filled with pressurized oxygen and continuously record temperature and pressure to identify the autogenous ignition point.
- Sample preparation: liquids or finely divided solids; sample mass typically 0.06 g to 0.5 g (examples use 0.3–0.5 g), adjusted for chamber volume.
- Reaction chamber size: practical chamber volumes quoted in the standard range 30 cm³ to 250 cm³.
- Oxygen purity: minimum 99.5% by volume; hydrocarbon content limited (see standard).
- Pressure: autogenous ignition temperature depends on oxygen pressure; for ranking the standard recommends a starting pressure of 100 bar when minimum ignition temperature is required.
- Instrumentation:
- Thermocouple close to sample with accuracy ±2 °C (25–500 °C).
- Pressure transducer accuracy 1% full scale.
- Heating: temperature raised at a constant rate; typical heating rates are 5–20 °C/min (high rates >20 °C/min may lower measured ignition temperature). Maximum test temperature 500 °C.
- Results: autogenous ignition temperature is taken where a sudden increase in both temperature and pressure begins; ΔT and Δp quantify reaction severity.
- Safety: apparatus and chamber must withstand violent internal reactions; purge procedure (pressurize to 10 bar then vent, repeated three times) to remove air.
Applications
- Material selection and ranking for oxygen service (seals, gaskets, lubricants, polymers) used in gas cylinders, valves and oxygen systems.
- Type testing to demonstrate oxygen compatibility of cylinder valves and accessories (supporting ISO 10297 compliance).
- Test laboratories providing oxygen‑compatibility data for manufacturers, safety assessments, and risk management.
Who uses this standard
- Cylinder and valve manufacturers
- Materials engineers and product designers for oxygen systems
- Accredited testing laboratories
- Safety and compliance officers in medical, industrial and aerospace gas supply sectors
Related standards
Keywords: ISO 11114-3, autogenous ignition test, oxygen compatibility, gas cylinders, non‑metallic materials, autogenous ignition temperature, ISO 10297.