Overview
ISO 13736:2021 - "Determination of flash point - Abel closed‑cup method" specifies the manual and automated Abel closed‑cup test for determining the flash point of combustible liquids. The method covers liquids with flash points between −30.0 °C and 75.0 °C, with stated precision valid for −8.5 °C to 75.0 °C. The standard defines apparatus design, sampling, test procedure, temperature measurement, pressure correction and reporting rules required to obtain reproducible closed‑cup flash point results.
Key topics and technical requirements
- Scope & limitations
- Applicable to combustible liquids in the stated temperature range.
- Not applicable to water‑borne paints (see ISO 3679).
- Liquids with halogenated compounds can give anomalous results.
- Manual thermometer limits upper manual test temperature to 70.0 °C.
- Principle
- Test portion is heated under continuous stirring in the Abel test cup. An ignition source is applied at intervals; the lowest temperature producing ignition across the liquid surface is recorded as the flash point.
- Apparatus and verification
- Detailed apparatus dimensions and requirements in Annex A.
- Thermometer installation and specifications in Annex B and Annex C; digital contact thermometers allowed if they meet accuracy and response requirements.
- Annex D (normative) covers apparatus verification using CRMs and secondary working standards.
- Measurement & controls
- Barometer with absolute pressure reading accurate to 0.5 kPa; flash point adjusted for atmospheric pressure deviations from 101.3 kPa.
- Timing device accuracy better than 5%.
- Cleaning solvents, coolants (ethylene glycol/water, glycerol/water or silicone oil), lubricants and appropriate ignitor/pilot gases are specified for correct operation.
- Precision and reporting
- Precision statements updated in line with ISO 4259‑1; full reporting requirements and details are provided in Clauses 11–14 and Annex E.
Practical applications
- Regulatory classification for shipping, storage and handling of flammable/combustible liquids.
- Quality control in petroleum, fuel and chemical manufacturing to detect volatile fractions or process consistency.
- Safety assessments used by HSE, transport authorities and emergency responders to determine storage/transport requirements.
- Laboratory testing for certification, supplier verification and preliminary investigation of unknown materials.
Who should use ISO 13736:2021
- Petroleum and fuel laboratories, chemical manufacturers, testing & calibration labs, regulatory agencies, transport & storage safety teams, and industrial hygiene professionals performing flash point testing using the Abel closed‑cup method.
Related standards
Keywords: ISO 13736:2021, Abel closed‑cup method, flash point determination, closed cup flash point, combustible liquids, flash point testing, test apparatus, flash point precision.
