ISO 4589-2:2017
- Specifies methods for determining the minimum volume fraction of oxygen (in a nitrogen mixture) that supports combustion of small vertical test specimens under specified conditions.
- Results are defined as Oxygen Index (OI) values.
- Methods provided for testing materials that are:
- Self-supporting in the form of vertical bars or sheets up to 10.5 mm thick.
- Solid, laminated, or cellular materials with apparent density ≥ 100 kg/m³.
- Potentially applicable to some cellular materials with apparent density < 100 kg/m³.
- A method is also provided for flexible sheets or film materials supported vertically during testing.
- Includes a comparative procedure to determine if the OI of a material exceeds a specified minimum value
ISO 4589-3:201
- Specifies methods for determining the minimum volume fraction of oxygen (in a nitrogen mixture) required to support combustion of small vertical specimens.
- Applicable over a temperature range of 25 °C to 150 °C (typically 40 °C to 150 °C).
- Results are expressed as temperature index values at the test temperature.
- Useful for evaluating material behavior under overheated service conditions typical in practical applications.












