Overview
ISO/TS 23877-1:2023 specifies an automated step‑wise cooling method for the determination of the pour point of petroleum and related products from natural or synthetic sources. The technique uses automated equipment that detects specimen movement during step‑wise cooling to identify the lowest temperature at which the sample will still flow. Results are normally reported in 3 °C testing intervals (some instruments can generate 1 °C intervals as an alternative, though precision/bias for 1 °C results have not been determined). This procedure is not suitable for crude oils.
Key topics and technical requirements
- Principle: After controlled preheating, the sample is cooled in steps and monitored for flow; the lowest temperature at which movement is detected is the pour point.
- Automated detection: Instruments may use optical reflection, CCD cameras, thermal sensing, or ultrasonic sensors to detect movement (see Annex A).
- Test interval: Standard testing intervals are 3 °C; 1 °C outputs are an acceptable alternative but lack established precision data.
- Apparatus & probes:
- Specified test jar dimensions and a contents mark for ~45 ml ±1 ml.
- Sample temperature probe (e.g., PT100) with at least 0.1 °C resolution and 0.5 °C accuracy.
- Cooling bath/jacket and anti‑moisture device to prevent contamination.
- Sample preparation:
- Preheat rules differ by expected pour point: samples with pour points above −33 °C have different preheat temperatures than those at or below −33 °C.
- If samples were heated >45 °C during transfer, allow 24 h at room temperature before testing.
- Calibration & verification:
- Follow manufacturer calibration procedures.
- Verify apparatus performance preferably at least twice a year using certified reference materials (ISO 17034); weekly in‑house checks (SQC) are recommended.
- Limitations: Not intended for crude oils; precision and bias for the new technique are still under study.
Applications and who uses it
- Quality control laboratories in refineries, petrochemical companies, fuel suppliers and lubricant manufacturers use this standard to assess low‑temperature flow properties.
- Instrument manufacturers use ISO/TS 23877-1 as a design and performance reference for automated pour‑point testers.
- Regulatory bodies and commodity specifiers reference the method for compliance testing of fuels, heavy lubricant base stocks and products containing residual fuel components.
- Practical benefits include improved repeatability through automation, reduced operator subjectivity compared with manual methods, and standardized reporting in 3 °C intervals.
Related standards
- ISO 3016 - manual pour point test (reference for traditional procedure)
- ISO 3170 / ISO 3171 - sampling of petroleum liquids
- ISO 17034 - certified reference material producers
- ISO 4259-4 - statistical quality control guidance
Keywords: ISO/TS 23877-1:2023, pour point determination, automated step-wise cooling method, petroleum products, pour point test, fuel oils, lubricant base stock, automated detection device.