Specification for indirect 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)|Gas space heating, Classification systems, Combustion, Safety valves, Marking, Flames, Flow rates, Performance testing, Gas valves, Convection heaters, Temperature control, Leak tests, Flues, Heat exchangers, Abrasion, Design, Performance, Ignition systems (heat engineering), Artificial weathering tests, Testing conditions, Flued heaters, Air, Air heaters, Automatic control systems, Warm-air heating, Test equipment, Weather resistance, Thermal efficiency, 2nd family gases, Gas flow, Flow measurement, Burners, Industrial, Combustion products, Safety measures, Fire safety, Commercial, Heat, Instructions for use, Heaters, Gas-powered devices