C405.2.2 Additional Lighting Controls
Exception: Additional lighting controls need not be provided in the following spaces:
- The override switch shall be in a readily accessible location;
- The override switch shall be located where the lights controlled by the switch are visible; or the switch shall provide a mechanism which announces the area controlled by the switch;
- The override switch shall permit manual operation;
- The override switch, when initiated, shall permit the controlled lighting to remain on for a maximum of 2 hours; and
- Any individual override switch shall control the lighting for a maximum area of 5,000 square feet (465 m2).
- The time limit shall be permitted to exceed 2 hours provided the override switch is a captive key device; and
- The area controlled by the override switch is permitted to exceed 5,000 square feet (465 m2), but shall not exceed 20,000 square feet (1860 m2).
Exception: Full automatic-on controls shall be permitted to control lighting in public corridors, stairways, restrooms, primary building entrance areas and lobbies, and areas where manual-on operation would endanger the safety or security of the room or building occupants
Exception: Daylight zones enclosed by walls or ceiling height partitions and containing two or fewer light fixtures are not required to have a separate switch for general area lighting.
Daylighting controls device shall be capable of automatically reducing the lighting power in response to available daylight by either one of the following methods:
- Continuous dimming using dimming ballasts and daylight-sensing automatic controls that are capable of reducing the power of general lighting in the daylit zone continuously to less than 35 percent of rated power at maximum light output.
- Stepped dimming using multi-level switching and daylight-sensing controls that are capable of reducing lighting power automatically. The system shall provide a minimum of two control channels per zone and be installed in a manner such that at least one control step is between 50 percent and 70 percent of design lighting power and another control step is no greater than 35 percent of design power.