Page 214 - Alternative Energy Systems in Building Design

190 ENERGY CONSERVATION

Lighting equipment certification The mandatory requirements for lighting-control
devices include minimum specifications for features such as automatic time-control
switches, occupancy-sensing devices, automatic daylighting controls, and indoor photo-
sensor devices. Most of the requirements are currently part of standard design practice in
California and are required for electrical plan checking and permitting.
Without exception all lighting-control devices required by mandatory measures
must be certified by the manufacturer before they can be installed in a building. The
manufacturer also must certify the devices to the CEC. On certification, the device is
listed in the Directory of Automatic Lighting-Control Devices.

Automatic time switches Automatic time switches, sometimes called time clocks,
are programmable switches that are used to automatically shut off the lights according
to preestablished schedules depending on the hours of operation of the building. The
devices must be capable of storing weekday and weekend programs. In order to avoid
the loss of programmed schedules, timers are required to incorporate backup power
provision for at least 10 hours during power loss.

Occupancy-sensing devices Occupancy-sensing devices provide the capability
to automatically turn off all lights in an area for no more than 30 minutes after the area
has been vacated. Sensor devices that use ultrasonic sensing must meet certain minimum
health requirements and must have the built-in ability for sensitivity calibration to
prevent false signals that may cause power to turn on and off unexpectedly. Devices
that use microwave detection (rarely used) principles likewise must have emission
controls and a built-in sensitivity adjustment.

Automatic daylight controls Daylighting controls consist of photosensors that
compare actual illumination levels with a reference illumination level and gradually
reduce the electric lighting until the reference level has been reached. These controls
are also deployed for power adjustment factor (PAF) lighting credits in the daylit areas
adjacent to windows. It is also possible to reduce the general lighting power of the con-
trolled area by separate control of multiple lamps or by step dimming. Stepped dim-
ming with a time delay prevents cycling of the lights, which is typically implemented
by a time delay of 3 minutes or less before electric lighting is reduced or is increased.
Light control in daylight is accomplished by use of photodiode sensors. It should be
noted that this requirement cannot be met with devices that use photoconductive cells.
In general, stepped switching-control devices are designed to indicate the status of
lights in controlled zones by an indicator.

Interior photosensor devices Daylight control systems in general use photo-
sensor devices that measure the amount of light at a reference location. The photo-
sensor provides light-level illumination information to the controller, which, in turn,
enables it to increase or decrease the area electric light level.
A photosensor devices must, as stated previously, be certified by the CEC. Devices
having mechanical slide covers or other means that allow for adjusting or disabling of
the photosensor are not permitted or certified.