ISO 13736:2021

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

• ISO 3679 (water‑borne paints testing)
• ISO 3170 / ISO 3171 (sampling petroleum liquids)
• ISO 15528 (paints/varnishes sampling)
• ISO 4259‑1 (precision definitions)
• ISO/TR 29662 (guidance on flash point testing)

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.