Recommends installation of closed heating appliances having an output of up to 45 kW, burning solid smokeless mineral fuel and fitted with factory-made insulated chimneys or combined chimney units. Covers room heaters, with or without boiler, cookers with integral boilers and independent boilers that provide heating or hot water. Includes definitions, ventilation, appliance output, materials and components, siting of appliances, pipework, air for combustion, draught stabilizers, ventilation of appliance enclosures, protective casing, dampers, accessibility of chimney assembly, warning plate, users' handbook, information on operation, maintenance and safety and safety precautions for the occupant.