The air volume flow ̇V in m3/h of all ventilated luminaires in a room is derived from the cooling load calculation which factors in all interior as well as exterior thermal loads as well as the comfort-related components of ventilation/air conditioning systems such as air velocity, temperature and humidity. Exterior cooling loads consist of heat input through walls, window areas and gap ventilation. Interior cooling loads consist of heat input by people, lighting, machines, material throughput (e.g. heated materials) and other sources (e.g. chemical reactions) as well as from adjacent rooms. A luminaire's air volume flow is calculated by dividing the entire air volume flow according to cooling load calculation for the room by the number of ventilated luminaires in the room. For normally clothed, sitting persons with light activity, standard EN ISO 7730 “Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria” specifies recommendations for the comfort criteria of room climates at which at least 80% of room occupants are satisfied.
