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