ISO/TR 15403-2:2006

ISO/TR 15403-2:2006 addresses the specifications of natural gas as a compressed fuel for vehicles as an addendum to ISO 15403-1. Specifically, ISO/TR 15403-2:2006 is intended to satisfy requests for quantitative data.
The critical items regarding gas composition are water content, sulfur compounds, particulate matter, higher hydrocarbons, CO2, free oxygen, glycol/methanol, oil content and corrosive components.
ISO/TR 15403-2:2006 pertains only to compressed natural gas as it enters the fuel containers on the vehicle. It does not apply to the natural gas delivered to a refuelling station.