DS EN 1020:2009 Non-Domestic Forced Convection Gas-Fired Air Heaters For Space Heating Not Exceeding A Net Heat Input Of 300 Kw Incorporating A Fan To Assist Transportation Of Combustion Air Or Combustion Products Describes the requirements and test methods for the safety and efficiency of non-domestic gas-fired air heaters having a fan to assist the transportation of combustion air and/or flue gases, hereafter