ISO 15911:2000

Overview

ISO 15911:2000 specifies an empirical procedure for estimating the net specific energy (lower heating value) of aviation turbine fuels from measured hydrogen content, together with sulfur content and density. The method is intended as a practical guide when an experimental calorimetric determination is unavailable or inconvenient. It applies only to liquid hydrocarbon aviation fuels produced by conventional refining (limited boiling ranges and compositions) and is not applicable to pure hydrocarbons.

Key topics and requirements

• Input parameters: mass fraction of hydrogen (measured to 0.01 % m/m), sulfur (to 0.02 % m/m) and density at 15 °C (to 0.5 kg/m³).
• Analytical methods referenced: hydrogen by IP 338 or ASTM D3701 (low-resolution NMR); density by ISO 3675 or ISO 12185; sulfur by ISO 4260 or ISO 8754.
• Calculation: an empirical correlation uses hydrogen, sulfur and density to compute net specific energy on a mass basis (MJ/kg) and can be converted to a volume basis (MJ/m³). Results are reported to the nearest 0.01 MJ/kg or 10 MJ/m³.
• Precision: repeatability r = 0.05 MJ/kg; reproducibility R = 0.06 MJ/kg (volume-basis guidance provided for typical densities).
• Applicability limits: correlation was derived from representative aviation fuels (Annex A) with hydrogen 13.00–14.14 % m/m, sulfur 0.01–0.33 % m/m, and density 789.0–830.5 kg/m³.
• Limitations and warnings: the method is empirical and should not replace experimental calorimetry when accuracy is required. Large errors are possible for fuels outside the defined class.

Practical applications

ISO 15911 is useful for:

• Fuel producers and refiners estimating energy content during production and QC when calorimetric testing is impractical.
• Laboratories and certification bodies preparing specification reports or preliminary assessments of aviation turbine fuels.
• Aerospace fuel specification writers and procurement teams requiring conservative energy estimates for contract/specification purposes.
• Researchers and engineers needing rapid estimates of calorific value from routine compositional and density data.

This standard supports workflows involving fuel energy estimation, energy density assessment, and calorific value estimation for aviation fuels where measured net specific energy is not available.

Related standards

Standards referenced for test methods and context:

• IP 338 / ASTM D3701 - hydrogen content by low-resolution NMR
• ISO 3675, ISO 12185 - density determination
• ISO 4260, ISO 8754 - sulfur determination
• ISO 91-1 - petroleum measurement tables (temperature corrections)
• ASTM D1655, DEF STAN and MIL-T specifications cited in Annex A (fuel classes used to derive the correlation)

Keywords: ISO 15911, net specific energy, aviation turbine fuels, hydrogen content, fuel energy estimation, calorific value, energy density, fuel specifications.