This international standard applies to packaged, self-contained or factory matched hydrogen generation systems with a capacity less than 400 m3/hr at 20 °C and 101,325 kPa, herein referred as hy drogen generators, that convert an input fuel to a hydrogen rich stream of composition and conditions suitable for the type of device using the hydrogen (e.g. a fuel cell power system or a hydrogen compression, storage and delivery system).It applies to hydrogen generators using one or a combination of the following input fuels: a) natural gas and other methane rich gases derived from renewable (biomass) or fossil fuel sources, e.g. landfill gas, digester gas, coal