ISO 3679:2022

Overview

ISO 3679:2022 specifies a small scale closed cup tester method for determination of flash point and flash no-flash results. The standard defines three procedures:

• Procedure A - rapid equilibrium flash no-flash (pass/fail at a specified temperature)
• Procedure B - rapid equilibrium flash point determination
• Procedure C - automated non‑equilibrium flash point determination

The method covers paints (including water-borne), varnishes, adhesives, solvents, petroleum products (including aviation turbine, diesel and kerosene fuels), fatty acid methyl esters (FAME / biodiesel) and related products over wide temperature ranges (procedures A/B: −30 °C to 300 °C; procedure C: −20 °C to 300 °C). The apparatus supports small test portions (2 ml or 4 ml) and can be made portable for on‑site testing.

Key topics and requirements

• Test procedures: Clear instructions for flash no-flash (A), flash point measurement (B) and automated flash point (C).
• Applicability: Specific product families and temperature ranges; suitability of FAME with a flash detector (A.1.6).
• Apparatus: Small scale closed cup tester design, verification and maintenance (Annex A, Annex B).
• Sampling & sample handling: Guidance for liquids, solids/semi‑solids and samples containing water (Clauses 8–9).
• Verification & calibration: Requirements for apparatus verification, temperature measuring device specs (Annex E) and use of cup inserts (Annex C).
• Precision and uncertainty: Precision statements (Clause 13), with procedure C precision assessed in the 40 °C to 135 °C range; repeatability and reproducibility criteria are described.
• Safety & limitations: Warnings about unstable, decomposable or explosive materials and method-dependent nature of flash point results.

Practical applications

• Regulatory classification for flammability, storage, transport and handling of fuels, solvents and paints.
• Quality control in fuel production, biodiesel (FAME) testing and paint/varnish manufacture.
• Rapid on‑site screening (flash no-flash) to decide if a product will ignite at a given temperature.
• Preliminary screening prior to more detailed compositional analysis.

Who should use ISO 3679:2022

• Test laboratories and QC teams in petroleum and paint industries
• Biodiesel and fuel producers assessing FAME flash behavior
• Safety, compliance and regulatory professionals responsible for classification and storage rules
• Manufacturers needing portable, small-sample flash point testing

Related standards

• ISO 1516, ISO 1523 (other closed cup equilibrium methods)
• ISO/TR 29662 (guidance on flash point testing and interpretation)
• Sampling and reference material standards cited in ISO 3679 (e.g., ISO 3170, ISO 3171, ISO 15528, ISO Guide 35)

Keywords: ISO 3679:2022, flash point, flash no‑flash, small scale closed cup tester, FAME, biodiesel, petroleum fuels, paints, on‑site testing, procedure A B C.