The terms Maintained and Non-Maintained are used to describe the mode of operation for an emergency lighting luminaire, and the decision on which mode of operation to use is determined by the use of the permises.
Maintained Emergency Luminaire
This is a luminaire in which the emergency lamps are lit all the time. Maintained mode is generally employed in places of assembly such as theatres, cinemas, clubs etc. The lights are typically dimmed when the premises are occupied, and the emergency escape lighting prevents total darkness.
Non-Maintained Emergency Luminaire
This is a luminaire whose lamps only come on when the power supply to the lighting fails. Non-Maintained lights are typically found in the work place where artificial lighting is normally deployed whilst the premises are occupied.
The classification of Maintained and Non-Maintained mode of operation can be further broken down or defined with the following classifications.
Combined Emergency Luminaire
This is luminaire which contains 2 or more sets of lamps, at least one of which is powered from the Emergency Lighting supply and the other(s) from the normal mains power supply. A combined emergency lighting luminaire can be either Maintained or Non-Maintained.
Compound self-contained Emergency Luminaire
This is a luminaire which operates in either Maintained or Non-Maintained mode, and also acts as the emergency lighting power supply to a satellite luminaire.
Satellite Emergency Luminaire
This is a luminaire which operates in either Maintained or Non-Maintained mode, and which derives it's emergency operation supply from an associated compound self contained emergency luminaire.