Streets, roadways, parking lots and pedestrian areas are only a few examples of outdoor areas that rely on superior lighting design for safety and efficiency. LED lighting is rapidly becoming a strong competitor to high-intensity discharge (HID) light sources for outdoor lighting. Kenneth Siderius, Invue marketing manager with Eaton’s Lighting Division, talked with us about LED and HID outdoor lighting sources and other outside lighting ideas, plus major design considerations for excellent lighting in outdoor spaces.
How should color be measured with outdoor lighting? What is the adequate range for outdoor lighting?
KS: The industry standard tends to be measured to 4000K correlated color temperature (CCT) at 70 color rendering index (CRI). Acceptable ranges are often 3000K-5000K CCT with a CRI of 70 or 80.
How do designs vary from street lighting to lighting for parks or other outdoor spaces?
KS: Each application represents a different set of visual tasks that need to be addressed through application of design technique and optical technology. Different environments have varying needs for security, way finding and the speed of recognizing details required to identify objects.
What considerations should you consider when planning an outdoor lighting design?
KS: When planning an outdoor lighting design, keep these five things in mind:
What role do light distribution and glare play in outdoor lighting design?
KS: Careful selection of lighting distribution will help ensure the visual environment is uniformly illuminated with luminaires that distribute the light at angles low enough to prevent excessive brightness and glare. This promotes visibility and the feeling of security.
In terms of energy efficiency, do HID lamps or LEDs perform better? Why is this important for outdoor area lighting?
KS: LED lighting has become more efficient than HID lamps in terms of both energy consumption and utilization of light, reducing the dollar per lighting lumen cost of ownership. Today the market is more thoroughly educated on LED sources, allowing end users to feel comfortable choosing LED lighting.
Is lumen depreciation a worry for either light source? How does LED durability factor into outdoor lighting?
KS: The lumen depreciation of HID fixtures drives a relamping requirement every three to five years. In contrast, LED luminaires extend the relamping requirement to more than 20 years. The low failure rates and reduced lumen depreciation of LEDs have extended the relamping maintenance cycle, reducing maintenance costs.
Overall, are HID lamps or LEDs a more cost-effective choice for outdoor area lighting?
KS: Modern LED lighting fixtures offer control options to turn off or reduce power when lighting is not required, saving energy and protecting the environment. If you also consider the low cost of ownership thanks to reduced energy consumption and maintenance needs, LEDs are a far better option.