Overview
EN ISO 22995:2019 - "Petroleum products - Determination of cloud point - Automated step‑wise cooling method" specifies an automated, optical detection approach to measure the cloud point of petroleum-derived liquids. It adapts the manual technique (ISO 3015) into an automated step‑wise cooling procedure suitable for routine laboratory testing. The standard is published by CEN/ISO and targets distillate fuels, fatty‑acid methyl esters (FAME), paraffinic diesel fuels and their blends, including products with flow‑improvers or additives intended for diesel engines and domestic heating.
Key topics and technical requirements
- Scope and applicability: Distillate fuels, FAME, paraffinic diesel and blends; may be applied to vegetable oils or lubricants but these were not part of the interlaboratory study (no precision data available).
- Principle: Step‑wise cooling of a sample while monitoring optically; the temperature at which the first cloud (wax crystals) appears is recorded as the cloud point.
- Apparatus essentials:
- Cylindrical clear glass test jar with defined dimensions and a marked sample height.
- Sample temperature probe positioned centrally with sensitive area ≤10 mm from the jar bottom; thermometer resolution 0.1 °C and accuracy 0.5 °C.
- Automated optical detection system capable of detecting cloud/wax appearance (detection at least every 1 °C).
- Jacket, anti‑moisture device and cooling bath conforming to the step‑wise cooling profile.
- Sample preparation and sampling: Samples must be homogeneous and moisture‑free; if needed, heat to at least 14 °C above the approximate cloud point (but ≤49 °C) and filter through lintless paper. Sampling follows ISO 3170 or ISO 3171.
- Precision and reporting: The standard includes sections on repeatability and reproducibility for evaluated fuel types; for unevaluated products (e.g., vegetable oils) precision data are not provided.
Applications and who uses it
- Quality control and acceptance testing in fuel laboratories, refineries and blending facilities.
- Verification of cold‑weather performance for diesel engine fuels and domestic heating fuels.
- Evaluation of additive and flow‑improver effectiveness on low‑temperature operability.
- Regulatory compliance testing and specification enforcement by standards bodies and fuel suppliers.
- Test equipment manufacturers implementing automated cloud‑point analyzers.
Related standards
- ISO 3015 - manual cloud point determination (background method)
- ISO 3170 / ISO 3171 - sampling of petroleum liquids (referenced normative documents)
EN ISO 22995:2019 is a practical, automated method for consistent cloud point measurement, supporting seasonal fuel management, product development and laboratory automation for cold‑flow property assessment.