This standard specifies requirements for providing documents for the operation, mainte-nance and use of heating systems in buildings requiring a trained operator.Parts of heating systems covered by this standard are:- boilers or heat supply equipment, including control;- safety arrangements, including air supply;- district heating heat exchangers, heat meters and primary domestic hot water production facilities;- energy sources, storage and supply;- flue gas systems, including condensate treatment and disposal;- heat distribution network, including associated components;- heat emitters, including accessories;- systems for control and supervision;- water treatments and procedures (e.g. chemical and physical, including antifreeze).