Overview
ISO/TR 19441:2018 - "Petroleum products - Density versus temperature relationships of current fuels, biofuels and biofuel components" - is a technical report that compiles recent density-versus-temperature measurements for modern fuel types and biofuel components. It focuses on how density changes with temperature and provides guidance to calculate the thermal expansion coefficient (α15) to convert measured density or volume to the standard reference temperature of 15 °C. The scope includes gasoline blends (E5, E10, E85), biodiesel/FAME and blends (B100, B7), domestic heating oils, paraffinic diesel (GTL/XTL/HVO) and other market fuels.
Key topics and technical contents
- Density vs temperature data: Measured results for current fuels and biofuel components across temperature ranges.
- Thermal expansion coefficient (α15): Procedures and examples to calculate α from measurement temperature to 15 °C.
- Volume Correction Factor (VCF) models: Discussion of applicable VCF approaches including exponential, linear and constant-value models for product families.
- Comparison with API Petroleum Measurement Tables (PMT): Evaluation of PMT constants and group constants (K0, K1, K2) and their suitability for new fuel types.
- Experimental methodology and precision: Guidance on density determination methods, participating laboratory protocols, measurement ranges and precision requirements relevant to calibration and trade.
- Treatment of atypical fuels: Recommendations for handling fuels with unusual density/temperature behavior and steps for harmonized introduction of new components.
- Supporting annexes: Worked examples, density/temperature tables and calculation examples (Annex A–E), and bibliography for further study.
Practical applications - who uses this standard
ISO/TR 19441:2018 is practical for:
- Fuel producers and blenders evaluating product families and designing blends (E-series, B-series, HVO, GTL/XTL).
- Test and calibration laboratories establishing density–temperature curves and calculating α15 for certificate issuance.
- Metrology and verification bodies ensuring compliance with calibration requirements and the EC Measuring Instruments Directive for volume meters.
- Retailers and fiscal/trade stakeholders needing accurate standard-volume calculations for invoicing and custody transfer.
- Standards committees and regulators deciding whether existing PMT models apply to new fuel components or when new group constants are needed.
Related standards and keywords
Related specifications and standards referenced include API MPMS chapters 11.1 / PMT, EN 228, EN 590, EN 14214, EN 15940, and DIN 51603-1.
Relevant keywords: ISO/TR 19441:2018, density versus temperature, thermal expansion coefficient, VCF, biofuels, biodiesel B100/B7, ethanol blends E5/E10/E85, paraffinic diesel, API PMT, fuel calibration, volume meters.
Note: The report finds PMT predictions acceptable for most fuels but identifies limitations for high-CME biodiesel blends, high-ethanol E85 variants and some paraffinic diesel products - recommending targeted testing when new fuel types enter the market.