Vreča za vzorce, ki še ni bila uporabljena za zbiranje vzorcev izpušnih plinov, se napolni z zrakom (ali kisikom) in referenčnim plinom NO, odmerjenima tako, da nastane mešanica, ki je v merilnem območju analizatorja.
A sampling bag which has not already been used to collect samples of exhaust gases shall be filled with air (or oxygen) and NO reference gas, which will be metered in such a way as to enable a mixture lying within the measuring range of the analyser to be obtained.