Division 6.4

All these tests may be conducted with the applicable market fuels. However, at the manufacturer's request, the reference fuels described in Annex IX shall be used. F1For engines fuelled with natural gas/biomethane (NG) or liquefied petroleum gas (LPG), including dual-fuel engines, the tests shall be performed with at least two of the reference fuels for each gaseous-fuelled engine, except in the case of a gaseous-fuelled engine with a fuel-specific type-approval where only one reference fuel is required, as described in Appendix 1 to Annex I. Where more than one gaseous reference fuel is used the results shall demonstrate that the engine meets the limit values with each fuel.