2 This method may not accurately determine the presence of corrosive materials if the sample contains corrosion inhibitors or other chemicals which diminish the corrosivity of the sample to the copper strip. Therefore, the addition of such compounds for the sole purpose of biasing the test method is prohibited. 3 At the request of the engine manufacturer, a higher MON be used to perform the type approval tests. 3.2. Type: Natural Gas/ Biomethane 3.2.1. Specification for reference fuels supplied with fixed properties (eg from a sealed container) As an alternative to the reference fuels set out in this paragraph, the equivalent fuels in paragraph 3.2.2. of this Annex may be used Limits Units Basis Test method minimum maximum Reference fuel GR Composition: Methane 87 84 89 Ethane 13 11 15 per cent Balance1 1 ISO 6974 — — mole Sulphur mg/m3 2 10 ISO 6326-5 — content Notes: 1 Inerts + C2+ 2 Value to be determined at standard conditions 293.2 K (20 °C) and 101.3 kPa. Reference fuel G23 Composition: Methane 92.5 91.5 93.5 per cent Balance1 1 ISO 6974 — — mole per cent N2 7.5 6.5 8.5 mole Sulphur mg/m3 2 10 ISO 6326-5 — — content Notes: 1 Inerts (different from N2) + C2+ C2+ 2 Value to be determined at 293.2 K (20 °C) and 101.3 kPa. Reference fuel G25 Composition: per cent Methane 86 84 88 mole per cent Balance1 1 ISO 6974 — — mole
2 This method may not accurately determine the presence of corrosive materials if the sample contains corrosion inhibitors or other chemicals which diminish the corrosivity of the sample to the copper strip. Therefore, the addition of such compounds for the sole purpose of biasing the test method is prohibited. 3 At the request of the engine manufacturer, a higher MON be used to perform the type approval tests. 3.2. Type: Natural Gas/ Biomethane 3.2.1. Specification for reference fuels supplied with fixed properties (eg from a sealed container) As an alternative to the reference fuels set out in this paragraph, the equivalent fuels in paragraph 3.2.2. of this Annex may be used Units Basis Limits Test method minimum maximum Reference fuel GR Composition: Methane 87 84 89 Ethane 13 11 15 Balance1 per cent mole — — 1 ISO 6974 Sulphur content mg/m3 2 — 10 ISO 6326-5 Notes: 1 Inerts + C2+ 2 Value to be determined at standard conditions 293.2 K (20 °C) and 101.3 kPa. Reference fuel G23 Composition: Methane 92.5 91.5 93.5 Balance1 per cent mole — — 1 ISO 6974 N2 per cent mole 7.5 6.5 8.5 Sulphur content mg/m3 2 — — 10 ISO 6326-5 Notes: 1 Inerts (different from N2) + C2+ C2+ 2 Value to be determined at 293.2 K (20 °C) and 101.3 kPa. Reference fuel G25 Composition: Methane per cent mole 86 84 88 Balance1 per cent mole — — 1 ISO 6974
ECE-TRANS-WP29-GRPE-76a3e.docx