Workrooms are all rooms in which workstations have been set up for employees. Hence residential rooms, changing rooms and lockers, staff rooms and similar rooms are not considered as workrooms. Work rooms have to satisfy a series of conditions with regard to ceiling heights, floor space, air space, lines of sight, Illumination and lighting, aeration and Ventilation as well as air conditioning. Some waivers exist for workrooms without permanent work- stations or parts of workrooms (see under Fictitious Partitioning) in which staff do not spend more than two hours a day (i.e. copying rooms).