- Outdoor lighting can be a valuable tool for enhancing the security and appearance of your facility.
- An effective lighting design should focus on proper light distribution and light output.
- Energy-efficient lighting technologies and control strategies can reduce costs while ensuring a safe and secure environment.
Exterior lighting is important for security as well as enhancing the appearance of your facility. While lighting patterns for parking lots and other outdoor spaces may seem simple, creating a design that makes the best use of that lighting can be complicated. The ultimate goal is to optimize light levels and distribution while minimizing energy use. Proper lighting design can be a valuable tool for increasing the overall security of your facility.
Brightest is not always the best
Insufficient light can compromise safety. As a result, lighting designs often focus on light output. While light levels are important, poor distribution can create over lighting in some areas and dark patches in others. "The conventional wisdom is that more light is better, but from a security standpoint, too much of the wrong kind of light, aimed in the wrong direction, can cause glare," according to Eric Richman, senior research engineer at the U.S. Department of Energy's Pacific Northwest National Laboratory. "Moreover, security camera function depends on various lighting factors including uniformity, contrast, light color and intensity. No one type of lighting will be best in all situations." (Lo Bosco 2012)
A foot-candle is a commonly used measure for the amount of light in a space. A study conducted by the Lighting Research Center at the Rensselaer Polytechnic Institute found that individuals felt safe and secure at one foot-candle; anything more did not improve their impressions.
Lighting for safety and security
A good lighting design integrates the most effective light sources with proper height and location to obtain the best coverage. The Illuminating Engineering Society, a leading authority on lighting design, outlines the most important considerations for effective safety and security lighting:
- Horizontal illuminance. The standard for assessing effective lighting because many tasks are horizontal in nature.
- Vertical illuminance. Critical for security issues because identifying objects and their movement is best done by viewing their vertical surfaces.
- Uniformity. Important for avoiding dark areas and enhancing the effectiveness of security cameras.
- Glare. Lighting aimed in the wrong direction can cause glare, reducing the visibility of occupants and security personnel.
To optimize savings and security, it is important to incorporate these design elements into an energy-efficient lighting strategy.
Energy-efficient outdoor lighting
So, how do you maintain a safe, secure environment while minimizing lighting costs? Effective strategies include reduced wattage lamps, energy-efficient upgrades and lighting controls.
Reduced wattage lamps. Metal halide and high-pressure sodium lamps are the most widely used technologies for outdoor lighting. Consider installing lower wattage lamps and fixtures in areas with excess light. One to three foot-candles of illumination at ground level is typically adequate for security. A simple, inexpensive light meter can be used to measure light levels around your facility.
Energy-efficient upgrades. Light-emitting diode (LED) technology is an effective replacement option for conventional lamps, offering higher energy efficiency, increased durability and longer rated life. LEDs may cost more to install than conventional lights, but due to their efficiency and long life, they can pay for themselves over time with lower operating and maintenance costs. For security purposes, LEDs provide more uniform distribution and whiter light for better contrast. Wal-Mart conducted several tests using LEDs for outdoor lighting and eventually installed them at a new store in Leavenworth, Kan. Customers who were surveyed reported feeling safe and secure with the new technology. (Hanford 2011)
Controls. Occupancy sensors and timers can save energy without compromising safety or security. Occupancy sensors activate all or some of the lights in an area when pedestrians or vehicles approach. For facilities with defined hours of operation, timers can switch lights on and off or dim them according to a set schedule. LEDs, with their instant-start and dimming capabilities, are an excellent fit for integration with lighting controls.
As with any investment, it is important to evaluate each technology and your specific lighting and security requirements before making a decision. Check with local government officials about lighting regulations before exploring any lighting project; many local governments have adopted ordinances that define light level and types.
Hanford, Desiree. "Case Study: Exterior LEDs Balance Safety, Security And Green At Wal-Mart." Building Operating Management. December 2011.
Illuminating Engineering Society. IESNA Lighting Handbook. 10th Edition. 2011.
Lo Bosco, Maryellen. "Excessive Lighting Does Not Improve Safety, Security." Building Operating Management. December 2012.