Businesses are always looking for ways to make their facilities stand out. In addition to added security, a well-designed outdoor lighting system can help you outshine the competition. If you are not certain about the power of good outdoor lighting, consider your own impression when you see a business that is poorly lit. A careful design with well-chosen lamps and fixtures can create an outdoor lighting system that minimizes energy costs while enhancing your facility.
Lighting affects human perception. An effective design will draw the eye toward a defined area and may increase foot traffic to a location. General considerations for outdoor lighting design include the following:
While these guidelines are helpful, they should not be applied to specific designs. The type of fixture, lamp, mounting height and spacing are likely to vary with each application.
A variety of lamp options are available, each with advantages and disadvantages when it comes to efficiency and performance. Choose lamp types that complement your facility and design needs.
For example, while high-pressure sodium (HPS) lamps are very efficient, retail or food service facilities may require higher quality lighting. Color rendering index (CRI) is the industry standard for evaluating lighting quality and is represented on a scale of 0 to 100. Incandescent lights have a CRI of 100 but are highly inefficient. Fluorescent lighting systems are widely used because of their good CRI, low unit brightness per linear foot and quick restart capabilities. Metal halide (MH) lamps also have good color rendering and are more tolerant of cold temperatures. Light-emitting diodes (LED) are a newer outdoor lighting technology. They offer energy efficiency, good color quality and long life. Their limited light output and directional nature make them unsuitable for lighting applications in certain areas, however.
Facility managers must balance energy efficiency with other performance factors to determine which technology is appropriate for their needs. The following table compares commonly used lamp types.
|Lamp||Efficacy (lumens/watt)||Color Rendering||Start Time||Light Output (lumens)||Service Life (hours)|
|Incandescent||8 to 25||100||None||60 to 6,000||750 to 4,000|
|Incandescent||30 to 95||60 to 95||Split-second||600 to16,000||7,000 to 36,000|
|HPS||50 to 150||20 to 85||5 to 10 minutes||2,500 to 100,000||10,000 to 30,000|
|MH||70 to 130||60 to 70||2 to 12 minutes||4,000 to 200,000||5,000 to 20,000|
|LED||35 to 100||70 to 90||None||60 to 12,000||50,000|
In addition to lamps, there are various types of light fixtures to consider.
Traditional pole-mounted floodlights are the most common choice because their mounting height and design spread the light across a wide area. Some fixtures can be mounted on the sides of buildings, making them a good choice for illuminating access doors or highlighting decorative foliage.
Many local governments have ordinances and building codes that define lighting levels and types. Consult with your local building inspector or a lighting design expert before mapping an outdoor lighting project.