Overview
EN ISO 3015:2019 (ISO 3015:2019) specifies a standardized laboratory method for determining the cloud point of petroleum and related products that are transparent in 40 mm layers and have cloud points below 49 °C. The scope explicitly includes diesel fuels (with up to 30 % (V/V) FAME), paraffinic diesel (with up to 7 % FAME), 100 % FAME and lubricants. The cloud point is defined as the temperature at which a cloud of wax crystals first appears when the sample is cooled under specified conditions.
Key topics and technical requirements
- Principle: Cool a prepared sample at a specified rate and periodically inspect the bottom of a test jar; record the temperature when a cloud is first observed.
- Sample preparation & sampling: Remove moisture and pour sample to the marked level in the test jar; sampling methods referenced to ISO 3170 / ISO 3171.
- Apparatus:
- Cylindrical clear glass test jar (outside diameter 33.2–34.8 mm, height 115–125 mm; sample height mark at 54 mm ± 3 mm).
- Temperature measuring devices: liquid-in-glass thermometers or digital contact thermometers (DCT) (normative device specifications are included).
- Cork, gasket, disc and a watertight metal jacket to hold the test jar.
- Controlled cooling bath (refrigeration or cooling mixtures; recommended mixtures in Annex B).
- Procedure details: Correct thermometer immersion, prevention of liquid-column separation, pre-cooling of jacket/disc, and observation intervals are specified.
- Results & precision: Methods for expression of results and precision statements (repeatability/reproducibility) are provided; the standard notes alignment of temperature ranges with established practice.
- Safety & limitations: Warning that hazardous materials and equipment may be involved; users must ensure appropriate safety measures.
Applications and who uses it
- Quality control and acceptance testing for diesel fuels, biodiesel (FAME blends), lubricants and other petroleum-derived liquids.
- Laboratories in refineries, fuel terminals, independent testing houses and regulatory bodies that require reproducible cloud point measurements for cold-weather performance assessment.
- Suppliers and purchasers specifying product acceptance criteria, and R&D teams evaluating fuel formulations or additive effects on low-temperature behavior.
Related standards
- ISO 3170 - Petroleum liquids: Manual sampling
- ISO 3171 - Petroleum liquids: Automatic pipeline sampling
- ASTM D7962, ASTM E644-11, ASTM E2877 - referenced for temperature sensor and thermometer practices
- Supersedes EN 23015:1994; endorsed by CEN as EN ISO 3015:2019
Keywords: EN ISO 3015:2019, ISO 3015:2019, cloud point test, petroleum products, FAME, diesel fuels, lubricants, test jar, digital contact thermometer, cooling bath.
