ISO 3924:2019

Overview

ISO 3924:2019 - Petroleum products - Determination of boiling range distribution - Gas chromatography method specifies a gas‑chromatographic (GC) procedure to determine the boiling range distribution of petroleum products and fractions with a final boiling point ≤ 538 °C. The method excludes gasoline and gasoline components and is intended for products with a boiling range > 55 °C and vapour pressure low enough for ambient‑temperature sampling. ISO 3924:2019 defines two GC procedures (A and B), calibration and reporting conventions (IBP, T10–T90, FBP), and precision/bias information.

Key topics and technical requirements

• Two procedures
  • Procedure A: Flexible - packed or capillary columns, non‑polar stationary phases (e.g., polydimethylsiloxane or silicone gum rubbers), detectors FID or TCD; analysis time ~14–60 min.
  • Procedure B: Accelerated - restricted to three capillary columns, no sample dilution, fast analysis (~8 min).
• Principle: Temperature‑programmed GC separates hydrocarbons by increasing boiling point; chromatogram area is converted to boiling temperatures using a retention‑time vs boiling‑point calibration.
• Calibration: Uses accurately weighed n‑alkane mixtures (typical C5–C44 components) in carbon disulfide; different concentrations for packed vs capillary columns; sample peaks (n‑alkanes) can aid calibration.
• Instruments & materials: Non‑polar stationary phases, solid supports for packed columns, carrier gas purity ≥ 99.995% (helium preferred for FID/TCD); hydrogen and nitrogen options discussed in Annexes E and F.
• Data outputs & definitions: IBP, T10/T30/T50/T70/T90, FBP based on percent area under chromatogram; slice rate, peak skewness and resolution checks required.
• Scope limits & compatibility: Applicable to samples containing up to ~20% FAME by volume; safety cautions for compressed gases (helium, nitrogen) and flammable hydrogen.

Practical applications and users

• Who uses ISO 3924:2019
  • Petroleum and petrochemical laboratories
  • Refinery QC and process control teams
  • Fuel analytics labs testing middle‑distillate and lubricant fractions
  • Biodiesel/fuel blending quality control (FAME compatibility)
  • Standards bodies and method validation scientists
• Why use it
  • Rapid, reproducible boiling range distribution by GC as an alternative/complement to physical distillation
  • Fast throughput (especially Procedure B) for routine QC
  • Useful for product specification, blend design, regulatory compliance and correlation to physical distillation (see Annex A)

Related standards

• ISO 3170, ISO 3171 - sampling of petroleum liquids (normative references)
• ISO 3405 - physical distillation correlation (Annex A assists conversion)
• Historical equivalence: IP 406 and ASTM D2887 (method origins)
• Annexes in ISO 3924:2019 cover n‑alkane boiling points, carrier gas alternatives, precision, and bias.

Keywords: ISO 3924:2019, boiling range distribution, gas chromatography method, petroleum products, Procedure A, Procedure B, GC calibration, n‑alkanes, FAME, fuel quality control.