This European Standard defines requirements and test methods concerning, in particular, the construction, safety as well as classification and marking of non-domestic flueless space heaters (including greenhouse heaters and diffusive catalytic combustion heaters), having a nominal heat input not exceeding 10 kW (Hs) burning 3rd family gases at nominal operating pressure not exceeding 50 mbar, referred to in the body of the text as 'appliances'. It covers the following types of appliance: a) fixed heaters; b) portable or mobile heaters including those that incorporate a compartment for a transportable refillable LPG cylinder.