This standard defines, for the purpose of type examination, the construction, the safety characteristics, the test methods and the marking of mobile and portable non-domestic forced convection direct fired air heaters with a rated heat input not exceeding 180 kW (Hs) and burning 3rd family gases, referred to in the body of the text as "appliances". This standard covers the following type of mobile and portable non domestic forced convection direct fired air heaters of type A3 (see CR 1749) fitted with an integral burner intended for use in other than residential dwellings: a) low gas pressure appliances operating at pressures up to and including 50 mbar burning commercial butane and/or commercial propane; b) medium gas pressure appliances operating at pressures above 50 mbar and up to 4,0 bar burning commercial butane and/or commercial propane. It does not apply to appliances which are intended to be fixed or permanently installed, or to appliances which incorporate liquid feed burners. Requirements for appliances given in this standard assume that the supply of gas from the gas cylinder will be governed by a pressure regulator. These appliances are not equipped with an appliance governor. Requirements for controls, given herein, relate to controls fitted as part of, or supplied with, particular appliances; they do not necessarily provide a complete specification for controls intended for general use. This Standard does not cover cylinders for liquefied petroleum gases or their associated regulators. There are no specific thermal efficiency requirements appropriate to these types of appliances as: c) all the heat produced by the combustion process is released into the space to be heated; d) the requirements with regard to the combustion performance, which is a safety matter, ensure the effective burning of the fuel gas.