ISO 37306:2025

Overview

ISO 37306:2025 specifies a laboratory micro‑distillation method for determining the distillation characteristics of liquid petroleum products at atmospheric pressure using an automatic micro distillation apparatus. It covers light and middle distillates (initial boiling points > 20 °C and end‑points below ≈ 400 °C) from petroleum, synthetic or biological sources, including automotive and aviation fuels, diesel and FAME blends, solvents and narrow‑boiling hydrocarbons. The method delivers fast results from small sample volumes and is technically equivalent to ASTM D7345.

Key topics and technical requirements

• Scope and applicability: Light and middle distillates, automotive spark‑ignition fuels (including up to 20% ethanol), aviation gasolines and turbine fuels, paraffinic diesel, FAME (B100), diesel blends up to 30% FAME, naphthas, kerosenes, burner and marine fuels, and narrow‑boiling solvents. Not applicable to products with appreciable residual material.
• Automatic apparatus: Uses a microprocessor‑controlled unit that automatically controls evaporation, measures vapour/liquid temperatures and flask internal pressure, and converts sensor data to percent recovered using defined algorithms.
• Measurements and definitions: Initial boiling point (IBP), final boiling point/end‑point (FBP), vapour and liquid temperature readings, per cent recovered/recovered predictions, and per cent residue.
• Apparatus and calibration: Requirements for micro distillation unit, barometer calibration, differential pressure sensors, temperature measurement systems, sampling devices and waste collection. Instrument verification, calibration and quality control procedures are specified.
• Procedure, calculations and reporting: Detailed test procedure, calculation methods, expression of results and required test report elements.
• Precision and performance: Repeatability and reproducibility statistics, bias considerations and specific precision guidance for FAME samples.
• Standards referenced: Sampling standards ISO 3170 and ISO 3171 are normative references; method is aligned with existing distillation methods.

Practical applications and users

• Who uses it: Petroleum and biofuel testing laboratories, refinery process control teams, fuel producers, quality control/assurance personnel, regulatory bodies, forensic/adulteration testing labs, and researchers.
• Why use it: Rapid, low‑volume assessment of boiling range and volatility for specification compliance, process monitoring, product quality screening, fuel blends verification and field/portable testing scenarios where conventional methods (e.g., ISO 3405, ASTM D1160) are slower or more sample‑intensive.
• Benefits: Faster turnaround, reduced operator subjectivity, small sample volume, and suitability for ethanol and FAME‑containing fuels within specified limits.

Related standards

• ISO 3170, ISO 3171 (sampling)
• ISO 3405 and ASTM D1160 (conventional distillation methods)
• ASTM D7345 (technical basis/equivalent)

Note: Follow all safety, hazardous materials and regulatory requirements when performing distillation testing.