These requirements cover room air conditioners rated not more than 600 volts alternating current (ac) and intended for installation in accordance with the National Electrical Code@ ANSI/NFPA 70. For the purposes of this standard@ room air conditioners include packaged terminal air conditioners@ special purpose air conditioners@ and recreational vehicle air conditioners. They are factory-made encased assemblies designed as a unit primarily to provide free delivery of conditioned air to an enclosed space@ room@ or zone. This equipment is intended for installation in a window@ through a wall@ or as a console located in or adjacent to the room@ zone@ or space to be conditioned. These units employ hermetic refrigerant motor-compressors with factory-charged refrigeration systems and include means for circulating air. They may also have provision for heating and ventilation. With regard to 1.2@ a console or in-wall type air conditioner may additionally serve a single adjacent room. Such units employ cabinet or enclosure constructions permitting attachment of an air discharge adapter or duct which extends into the adjacent room. Recreational vehicle air conditioners may also employ a limited amount of ductwork. These requirements do not cover equipment intended for connection to duct systems for the purpose of providing central cooling@ heating@ or both.