22 August 2006
Daylight-based controls detect the amount of daylight in a space and either
dim luminaires accordingly or switch off unnecessary luminaires. Sensors must be
located according to manufacturer's recommendations and be adjusted so that short
changes in daylight (caused by passing clouds) do not trigger the sensor.
Occupancy-based controls detect individuals with passive infrared, ultrasonic,
or dual technology. They may be ceiling mounted to cover large spaces or they may be
integrated with wall switches for smaller spaces. Occupancy sensors are ideal for areas
of convenience such as storage rooms where individuals often have their hands full
when entering or leaving. Refer to Chapter 5 "Lighting Equipment" for more detail on
types of occupancy-based controls.
Timed switching can be incorporated into wall switches for small spaces.
These are ideal for janitor closets or other areas where the lighting might otherwise be
Timeclocks control larger areas or groups of luminaires. They are often
incorporated with photocells to control exterior luminaires. In such cases, the daylight
sensor may turn luminaires on at dusk and then all luminaires are turned off by the
timeclock at a preset time.
Personal Control typically refers to a Digital Addressable Lighting Interface
(DALI) system. Control devices that utilize this protocol allow individual luminaires to be
"addressed" to an individual workstation. This provides an occupant with the ability to
control and dim his or her own luminaire even in an open office configuration.
Building-wide control systems may monitor as well as control the lighting
systems throughout the building. Often, devices are combined to control both HVAC
and lighting systems.
Sustainability refers to a broad range of design strategies aimed at reducing
the resource use and environmental impact of the built environment. Areas of concern
include energy efficiency, resource conservation, reuse, and recycling, indoor air
quality. The concept of holistic design brings all of these issues into consideration. This
design approach integrates various building disciplines and systems. Integrated design
requires an understanding of how one building system affects other systems and how to
optimize their interdependence. For example, utilizing energy efficient light sources and
turning off fixtures that are not required, minimizes electricity requirements for the
building lighting system. However, these same strategies also reduce the amount of
heat produced by all light sources. With this reduction in heat, a smaller mechanical
system may be required to cool the building. Less space required for mechanical
equipment may mean more space for program requirements.
Requirements for sustainable design:
Use the most energy efficient light source suitable for the application.