Specification for direct gas-fired forced convection air heaters with rated heat inputs greater than 330 kW but not exceeding 2 MW for industrial and commercial space heating. Safety and performance requirements (excluding electrical requirements) (2nd family gases)|Convection heaters, Gas space heating, Combustion products, Safety devices, Ignition systems (heat engineering), Gas flow, Combustion, Scratch tests, Flow rates, Heat, Heaters, Commercial, Design, Flames, Safety valves, Temperature control, Artificial weathering tests, Gas valves, Air heaters, 2nd family gases, Test equipment, Air, Performance, Marking, Automatic control systems, Industrial, Instructions for use, Classification systems, Burners, Testing conditions, Gas-powered devices, Warm-air heating, Temperature rise, Watertightness tests, Fire safety, Performance testing