ISO 2592:2017

Overview

ISO 2592:2017 - "Petroleum and related products - Determination of flash and fire points - Cleveland open cup method" - specifies the standardized procedure for measuring open cup flash point and fire point of petroleum products using the Cleveland open cup apparatus. It applies to products with open cup flash points between 79 °C and 400 °C, excluding fuel oils commonly tested by the closed‑cup method (see ISO 2719). The standard aligns with ASTM D92 and includes requirements for apparatus, sample handling, measurement, verification and precision.

Key topics and requirements

• Scope & definitions: Clear definitions of flash point and fire point (fire point = ignition sustained for ≥ 5 s), and applicability limits (79–400 °C).
• Test principle: Heat the test portion (initially at a faster rate, typically 5–17 °C/min, then slower 5–6 °C/min near the flash point) and pass a small test flame across the open cup at intervals to detect ignition. Results are corrected to standard atmospheric pressure.
• Apparatus & measuring devices: Cleveland open cup apparatus (Annex A). Temperature measuring devices must meet accuracy and response criteria (Annex B). Barometer required (absolute pressure accuracy 0.5 kPa; resolution 0.1 kPa); pre‑corrected sea‑level barometers shall not be used.
• Sample handling & sampling: Follow ISO 3170 / ISO 3171 for sampling. Subsample at least 56 °C below expected flash point; handle water, semi‑solids and skin‑forming materials per the method (Annex D offers an alternative for skin formation).
• Verification & standards: Annual verification against a Certified Reference Material (CRM) or more frequent checks with Secondary Working Standards (SWS). Verification acceptance: result within R/√2 of the CRM certified value, where R is method reproducibility.
• Precision: Repeatability and reproducibility specified; reproducibility aligned with ASTM D92 and updated to 18 °C in this edition.
• Automation: Automated testers permitted if demonstrated to produce results within method precision; manual testing is the referee method in disputes.

Applications and users

ISO 2592:2017 is used for:

• Quality control and batch testing in refineries, petrochemical plants and lubricant manufacturers
• Product classification, labeling and regulatory compliance (storage, handling, transport safety)
• Safety officers and risk assessment for flammability and fire protection planning
• Test laboratories and certification bodies validating equipment or issuing certificates

Typical users: analytical chemists, laboratory managers, QC engineers, safety/compliance personnel, equipment manufacturers and calibration labs.

Related standards

• ISO 2719 - Closed cup flash point (fuel oils and many fuels)
• ASTM D92 - Cleveland open cup method (aligned with ISO 2592)
• ISO 3170 / ISO 3171 - Sampling petroleum liquids

Keywords: ISO 2592:2017, Cleveland open cup, flash point, fire point, petroleum products, open cup method, ASTM D92, ISO 2719, sampling, CRM, verification.