Wall Pack Lights: How to Adjust Light Distribution
Wall pack lights are a staple in commercial and industrial exterior lighting, widely used for building perimeters, loading docks, and parking garages. Unlike general floodlights, wall packs are designed to be mounted directly onto vertical surfaces. A critical factor in their performance is light distribution—how the light is spread across the intended area. Properly adjusting and selecting the right light distribution ensures energy efficiency, minimizes light pollution, and maximizes safety by eliminating dark spots or excessive glare［1］.
Understanding Light Distribution Patterns
The distribution of light from a wall pack is determined by the fixture's optical design, specifically the reflector and the lens. In the lighting industry, these distributions are often categorized by standard types defined by organizations such as the Illuminating Engineering Society (IES). Understanding these patterns is the first step in adjusting your lighting layout.
- Type III (Medium Spread): This is the most common distribution for general wall packs. It projects light outward in a symmetrical or asymmetrical pattern that is wider than it is deep. It is ideal for general area lighting, such as building perimeters and walkways, where the mounting height is moderate (typically 15 to 25 feet)［2］.
- Type IV (Forward Throw): Also known as "Forward Throw" or "Asymmetrical," this pattern directs the majority of the light forward, away from the wall. This is crucial for illuminating areas directly in front of the fixture, such as parking lots or loading docks, while minimizing light falling on the building facade itself.
- Type V (Square/Circular): While less common for standard wall packs, some high-output models offer a symmetrical distribution (Type V) that spreads light evenly in all directions. This is typically reserved for pole-mounted area lighting but can be found in corner-mounted wall pack applications［3］.
- Type II (Short Spread): This pattern is designed for narrow pathways or walkways where the light needs to be distributed along the path rather than thrown far outward.
Mechanical Adjustment: Physical Positioning
Unlike indoor downlights or troffer lights which are often fixed within a ceiling grid, wall pack lights offer specific mechanical adjustments that can alter light distribution after installation.
1. Vertical Aiming (Tilt Adjustment)
Many modern LED wall packs, particularly those designed for high-wattage applications (replacing Metal Halide), feature a pivoting bracket. This allows the installer to adjust the vertical angle of the fixture.
Many modern LED wall packs, particularly those designed for high-wattage applications (replacing Metal Halide), feature a pivoting bracket. This allows the installer to adjust the vertical angle of the fixture.
- Adjustment: Loosening the pivot bolts allows the fixture to be tilted up or down.
- Effect: Tilting the fixture slightly downward concentrates the light closer to the base of the wall, increasing foot-candles on the ground immediately adjacent to the building. Tilting it slightly upward (though generally discouraged to prevent glare) throws the light further out into the distance［4］.
2. Horizontal Orientation
While wall packs are usually mounted parallel to the wall, the choice of mounting location dictates the horizontal distribution.
While wall packs are usually mounted parallel to the wall, the choice of mounting location dictates the horizontal distribution.
- Corner Mounting: Placing a wall pack at a 45-degree angle in a corner allows a single fixture to illuminate two sides of a building, effectively splitting the light distribution pattern to cover a wider angular sector.
- Alternating Orientation: In long corridors or loading docks, alternating the aim of adjacent fixtures (angling them slightly inward toward the center of the path) can create a more uniform light distribution and reduce the "striping" effect often caused by regularly spaced lights［5］.
Optical Adjustment: Selecting the Right Lens and Reflector
For fixed wall packs (which lack mechanical tilt), "adjusting" the distribution happens at the specification and design phase. This involves selecting the correct optical components.
Reflector Geometry
The shape of the aluminum reflector inside the housing is the primary driver of the beam angle.
The shape of the aluminum reflector inside the housing is the primary driver of the beam angle.
- Smooth Reflectors: These provide a sharper beam edge and are often used when precise cutoff is needed to prevent light form spilling onto adjacent properties (Dark Sky compliance)［6］.
- Textured/Specular Reflectors: These scatter the light slightly more, creating a softer transition between light and dark areas. This is often used in Type III distributions to ensure a smooth gradient of light across a wall surface.
Lens Options
The lens acts as the final filter for light distribution.
The lens acts as the final filter for light distribution.
- Clear Lens: Allows for maximum efficiency (lumens per watt) but results in a more defined beam pattern based strictly on the reflector.
- Frosted/Prismatic Lens: These lenses diffuse the light. While they slightly reduce total output efficiency, they significantly improve uniformity. They are essential for applications where the "hotspot" of the LED array needs to be softened to prevent glare for drivers or pedestrians［7］.
Electrical Adjustment: Dimming and Control
Modern LED wall packs are rarely just "on" or "off." Adjusting the intensity of the light is a form of distribution control, managing how much light reaches a surface at any given time.
0-10V Dimming
Most commercial wall packs come with 0-10V dimming drivers. This allows facility managers to lower the light output during late-night hours when traffic is low.
Most commercial wall packs come with 0-10V dimming drivers. This allows facility managers to lower the light output during late-night hours when traffic is low.
- Application: A loading dock may require 100% output (full distribution) during shipping hours but can be dimmed to 50% or 30% after midnight. This does not change the angle of the light, but it adjusts the density of the light distribution, saving energy and reducing light trespass［8］.
Motion Sensors and Occupancy
Integrating motion sensors (microwave or PIR) effectively changes the temporal distribution of light. The fixture remains in a low-output state (often acting as a safety nightlight) and ramps up to full distribution only when movement is detected. This is highly effective for energy conservation in parking structures and alleyways［9］.
Integrating motion sensors (microwave or PIR) effectively changes the temporal distribution of light. The fixture remains in a low-output state (often acting as a safety nightlight) and ramps up to full distribution only when movement is detected. This is highly effective for energy conservation in parking structures and alleyways［9］.
Application-Specific Distribution Strategies
To maximize the utility of wall pack lights, the distribution strategy must match the environment.
| Application | Recommended Distribution | Reason |
|---|---|---|
| Building Facades | Type III (Symmetrical) | Provides even wash up and down the wall for aesthetics and security. |
| Loading Docks | Type IV (Forward Throw) | Pushes light out toward the trailer/truck, keeping the dock floor bright without blinding the driver. |
| Walkways | Type II or Type III | Focuses light on the path without spilling into landscaping or windows. |
| Parking Lots | Type IV (High Output) | Replaces pole lights in tight spaces, throwing light far into the lot from the building edge. |
Conclusion
Adjusting light distribution for wall pack lights is a combination of selecting the correct IES photometric type (Type III vs. Type IV), utilizing mechanical tilt features where available, and employing the correct lensing for diffusion. By understanding these variables, facility managers and lighting designers can ensure that wall pack lights provide safe, uniform illumination while adhering to energy codes and minimizing light pollution.
References
［1］ (Illuminating Engineering Society) IES Lighting Handbook: Application of Light and Illuminating Criteria - https://www.ies.org/standards/lighting-fundamentals/
［2］ (Energy.gov) Outdoor Area Lighting | Department of Energy - https://www.energy.gov/energysaver/outdoor-area-lighting
［3］ (DarkSky International) Outdoor Lighting Principles - https://darksky.org/what-we-do/lighting/lighting-principles/
［4］ (LED Professional) Optics and Thermal Management in LED Lighting - https://www.led-professional.com/technology/light-sources/optics-and-thermal-management-in-led-lighting
［5］ (Lighting Research Center) Exterior Lighting for Safety and Security - http://www.lrc.rpi.edu/programs/transportation/SSL/exterior.asp
［6］ (DesignLights Consortium) Technical Requirements for Solid State Luminaires - https://www.designlights.org/technical-requirements/
［7］ (Lumissil Microsystems) LED Lensing and Beam Angles - https://www.lumissil.com/technology/led-lensing
［8］ (EPA Energy Star) Commercial Lighting Controls - https://www.energystar.gov/products/commercial_lighting_controls
［9］ (Navigant Consulting) Energy Savings from Networked Lighting Controls - https://www.energy.gov/eere/ssl/articles/energy-savings-and-financial-analysis-networked-lighting-controls
［2］ (Energy.gov) Outdoor Area Lighting | Department of Energy - https://www.energy.gov/energysaver/outdoor-area-lighting
［3］ (DarkSky International) Outdoor Lighting Principles - https://darksky.org/what-we-do/lighting/lighting-principles/
［4］ (LED Professional) Optics and Thermal Management in LED Lighting - https://www.led-professional.com/technology/light-sources/optics-and-thermal-management-in-led-lighting
［5］ (Lighting Research Center) Exterior Lighting for Safety and Security - http://www.lrc.rpi.edu/programs/transportation/SSL/exterior.asp
［6］ (DesignLights Consortium) Technical Requirements for Solid State Luminaires - https://www.designlights.org/technical-requirements/
［7］ (Lumissil Microsystems) LED Lensing and Beam Angles - https://www.lumissil.com/technology/led-lensing
［8］ (EPA Energy Star) Commercial Lighting Controls - https://www.energystar.gov/products/commercial_lighting_controls
［9］ (Navigant Consulting) Energy Savings from Networked Lighting Controls - https://www.energy.gov/eere/ssl/articles/energy-savings-and-financial-analysis-networked-lighting-controls