ISO 14912:2025 · Annex D
Conversion validation
Agreement with the reference examples
These comparisons calculate the published example inputs using the same conversion library as the converter. Calculated fractions are shown in the same notation and precision as the published references.
Natural gas at 0 °C
D.2.1 · Table D.1 · Reference conditions 2
Volume output at 0 °C and 101.325 kPa absolute pressure.
All values match at the published precision.
| Component | Calculated | Reference |
|---|---|---|
| Ethane | 3.4758e-2 | 3.4758e-2 |
| Propane | 9.6225e-3 | 9.6225e-3 |
| n-Butane | 2.1125e-3 | 2.1125e-3 |
| Isobutane | 3.2796e-3 | 3.2796e-3 |
| n-Pentane | 5.5673e-4 | 5.5673e-4 |
| Nitrogen | 1.7546e-2 | 1.7546e-2 |
| Carbon dioxide | 6.7749e-3 | 6.7749e-3 |
| Methane | 9.2535e-1 | 9.2535e-1 |
Natural gas at 25 °C
D.2.1 · Table D.1 · Reference conditions 1
Volume output at 25 °C and 101.325 kPa absolute pressure.
All values match at the published precision.
| Component | Calculated | Reference |
|---|---|---|
| Ethane | 3.4810e-2 | 3.4810e-2 |
| Propane | 9.6654e-3 | 9.6654e-3 |
| n-Butane | 2.1356e-3 | 2.1356e-3 |
| Isobutane | 3.3081e-3 | 3.3081e-3 |
| n-Pentane | 5.6924e-4 | 5.6924e-4 |
| Nitrogen | 1.7537e-2 | 1.7537e-2 |
| Carbon dioxide | 6.7807e-3 | 6.7807e-3 |
| Methane | 9.2519e-1 | 9.2519e-1 |
Gravimetric preparation
D.2.2.2–D.2.2.3 · Mass-to-mole conversion
Mole output does not require a reference state.
All values match at the published precision.
| Component | Calculated | Reference |
|---|---|---|
| Carbon dioxide | 0.043034 | 0.043034 |
| Nitrogen | 0.067605 | 0.067605 |
| Ethane | 0.062984 | 0.062984 |
| Methane | 0.82638 | 0.82638 |
Reading the comparison
All table values are fractions, not percentages. Matching values agree at the precision published in Annex D; unrounded calculations may differ beyond the last printed digit.
Scope and interpretation
The natural-gas cases use the completed composition with methane determined by difference, not the alternative normalized analysis in Table D.1. Pentanes are represented by n-Pentane, as in the example. The standard brackets the pentane volume fractions because they describe a hypothetical gaseous state at these conditions; numerical agreement does not establish phase applicability.
These comparisons cover the central fraction values in D.2.1 and D.2.2. They do not validate the examples' uncertainty and covariance calculations, concentration conversions, the complete Annex C catalogue, or full phase and applicability assessment. This is independent validation evidence, not certification or a claim of complete ISO 14912 coverage.