ISO/TR 29662:2020

Overview - ISO/TR 29662:2020 (Flash point and combustibility testing)

ISO/TR 29662:2020 is a Technical Report from ISO providing guidance on flash point testing and combustibility testing for petroleum products and other liquids. It gives an overview of established test methods, advice on application and specification development, and highlights key aspects such as definitions, instrumentation, safety, calibration and reporting. The document is intended for laboratory managers, technicians, regulators, specification writers and industry; it is not a comprehensive step‑by‑step manual or an exhaustive interpretation of results.

Key topics and technical requirements

• Definitions and concepts: widely used definitions of flash point, fire point, sustained combustibility and sustained burning; flash point values must be related to specific test methods and apparatus.
• Test method selection: guidance on choosing methods (e.g., open cup vs closed cup), and on classifications of tests - non‑equilibrium, equilibrium, and rapid equilibrium methods.
• Instrumentation and detection: recommendations for ignition sources, flash detection, stirring systems and temperature measurement (including sub‑ambient testing).
• Calibration and verification: procedures for instrument calibration and routine verification to ensure accuracy and repeatability and reproducibility.
• Sample handling: special guidance for volatile samples, viscous/semi‑solid materials, biodiesel (B100 FAME), mixtures and samples that form a skin during testing.
• Safety and environment: testing environment requirements and safety precautions for handling flammable liquids.
• Reporting and corrections: how to express results, apply barometric pressure correction (adjustment from 101,3 kPa) and document precision and uncertainty.
• Annex A: informative list of major test methods and typical temperature ranges used in specifications and regulations.

Practical applications and users

• Use ISO/TR 29662:2020 to:
  • Select appropriate flash point or combustibility test methods for product specifications and regulatory compliance.
  • Develop or review laboratory procedures and quality control practices (calibration, verification, reporting).
  • Assess applicability of methods for challenging samples (biodiesel, high viscosity, skinning samples).
  • Inform safety assessments, transport classification and storage decisions based on fire point and sustained combustion criteria (e.g., sustained burning defined as burning continuing ≥15 s after ignition removal; fire point often defined as sustaining ≥5 s).
• Typical users: test laboratories, fuel and lubricant manufacturers, regulators, standards writers and safety officers.

Related standards

• Normative references include ISO 1998‑1 and ISO 1998‑2 (petroleum industry terminology). The report was developed by ISO/TC 28 (Petroleum and related products).

Keywords: ISO/TR 29662:2020, flash point testing, combustibility testing, petroleum products, fire point, sustained combustion, open cup, closed cup, biodiesel, barometric correction, calibration.