Sustainable Facilities Tool

Shading/Glare Control

Glare, or excessive brightness contrast within the field of view, is an aspect of daylighting that can cause discomfort and eye strain to occupants. It is important to reduce glare and minimize direct sunlight exposure in the vicinity of critical visual tasks. Incorporate shading devices and window glazing technologies to keep work environments healthy and productive. Strategies such as:

• Roof overhangs
• External scrim
• Louvers
• Window coatings

can minimize glare and solar heat gain when coupled with internal technologies like automated shading devices and directional blinds.

Bundles: Optimizing Daylighting Optimizing Daylighting

System Relationships

Emergency/Security lighting

Emergency lighting is critical to any building design and can be designed for minimal energy use. Replacing an older exit sign that is on 24 hours per day, with a single LED-lit replacement can save you more than $300 over its lifetime(1). Battery-backed lighting devices come on automatically when a building experiences a power outage and allows occupants to continue basic activities or find exit opportunities through corridors and stairwells. LEDs coupled with lenses and reflectors are an increasingly popular and environmentally conscious option to highlight escape routes via exit signs and stairway illumination.

(1) Adapted from the “ENERGY STAR Exit Sign Savings Calculator”, http://www.energystar.gov/index.cfm?c=exit_signs.pr_exit_signs

System Relationships

Outdoor lighting

Outdoor lighting typically serves one or more of the following purposes: aesthetics, security, and/or utility. Facade, parking, and walkway lighting present a tremendous opportunity for savings, as these lights are on for nearly half the year. Outdoor lighting should be downward facing to limit light pollution and designed to reduce light trespass. Reflectors, deflectors, and covers can be used to maximize the efficiency of the light source. Outdoor lightings systems, coupled with lighting controls such as motion detectors and photosensors, ensure an energy efficient and safe area beyond the building facade. The most common lamps used for outdoor lighting are HIDs, but LEDs are becoming more popular as a viable, efficient, and more responsive alternative.

System Relationships

Lighting Controls

Lighting controls can be used to manually or automatically turn lights on and off or control lighting levels according to daylight conditions. Lighting controls are critical for minimizing energy use, maximizing space functionality, and user satisfaction. Common types of lighting controls include manual controls like switch dimmers and automated controls such as motion sensors, occupancy sensors, photosensors, and timers.

• Occupancy sensors – Occupancy sensors detect activity within a predetermined indoor area and turn lights on automatically when the space is occupied or off when the space is unoccupied. Occupancy sensors are an effective technology at improving the lighting system’s energy efficiency.

  “There are two types of occupancy sensors: ultrasonic and infrared. Ultrasonic sensors detect sound, while infrared sensors detect heat and motion. In addition to controlling ambient lighting in a room, they are useful for task lighting applications, such as over kitchen counters.” http://www.energysavers.gov/your_home/lighting_daylighting/index.cfm/mytopic=12210

• Photosensors – Photosensors detect daylight light conditions and adjust electric light accordingly. Vital for outdoor applications, photosensors ensure that the outdoor lighting system is functioning when needed. Photosensors within the interior of the building can be used to turn off or dim electric lighting in response to sufficient natural light levels provided by daylighting.
• Motion sensors – Motion sensors, primarily used outdoors for safety near areas where light isn’t always necessary, automatically turn on when motion is detected.

  “Motion sensors automatically turn outdoor lights on when they are needed (when motion is detected) and turn them off a short while later. They are very useful for outdoor security and utility lighting. Because utility lights and some security lights are needed only when it is dark and people are present, the best way to control might be a combination of motion sensor and photosensor. Incandescent flood lights with a photosensor and motion sensor may actually use less energy than pole-mounted high-intensity discharge (HID) or low-pressure sodium security lights controlled by a photosensor. When turned on, HID and low-pressure sodium lamps can also take up to ten minutes to produce light. Therefore, they do not work well with just a motion sensor.” http://www.energysavers.gov/your_home/lighting_daylighting/index.cfm/mytopic=12200

• Dimmers – Dimmer controls provide variable indoor lighting. By dimming lamps, energy savings can be achieved by reducing wattage and output.

  “Dimming fluorescents requires special dimming ballasts and lamp holders, but does not reduce their efficiency. Fluorescent dimmers are dedicated fixtures and bulbs that provide even greater energy savings than a regular fluorescent lamp. Off-the-shelf dimmers for incandescent fixtures are inexpensive and provide some energy savings when lights are used at a reduced level. Dimmers also increase the service life of incandescent lamps significantly. However, dimming incandescent lamps reduces their lumen output more than their wattage. This makes incandescent lamps less efficient as they are dimmed” http://www.energysavers.gov/your_home/lighting_daylighting/index.cfm/mytopic=12190

• Timers – Timers can be programmed to turn on and off both indoor and outdoor lights at specified times. Timers, paired with other lighting control technologies, can be useful to ensure lighting does not remain on past primary building hours.

Bundles: Economic Lighting Upgrade Optimizing Daylighting Optimizing Daylighting

System Relationships

Task Lighting

Task lighting is any supplemental lighting source that assists in performing a localized and visual task. In the office environment, providing task lighting at individual workstations and desks allows occupants control of their visual space and could reduce the need for general lighting. Task lighting can come hard-wired in a desk or be as simple as a desk lamp. Consider the use of LED bulbs and lamps with articulated arms to provide even greater energy savings and positive ergonomics.

System Relationships

Furniture and Furnishings

The furniture and corresponding building space layout plays an important role in a successful lighting system. Furniture dimensions and orientation have a tremendous impact on the effectiveness of general lighting. A daylight-optimized interior design considers furniture design, placement, and finishes to enhance lighting performance. For example, positioning work surfaces at a distance from sun-oriented facades reduces the need for shading and permits greater penetration of daylight. Choose finishes that reflect light without causing glare. Maximize views to the outdoors through furniture orientation and space layout. The use of transparent or translucent panels within the workspace and centrally locating private offices can go a long way towards optimizing views and daylight to occupants.

(Example) By positioning work surfaces at a distance from the south facade, solar control is easier with smaller solar shading devices than if a desk or office is placed directly against the south facade. This concept is illustrated in the following figure, and shows how a relatively small overhang provides full direct seasonal solar protection to the workspace. The area immediately adjacent to the south facade is circulation space.
Source: http://www.wbdg.org/resources/daylighting.php

System Relationships

Surface Reflectance

Office (walls, floors, and ceilings) and furniture surfaces should be of light color, high reflectance value, low glare, and low contrast. This avoids high contrast with visual tasks and reduces the output required of the lighting system, making it more visually comfortable, economical, and energy efficient.

Bundles: Economic Lighting Upgrade

System Relationships

Daylighting

An effective daylighting strategy sufficiently illuminates the building space through side-lighting and top-lighting apertures like windows and skylights, without subjecting occupants to inconvenient glare or light level fluctuations. Daylight can be reflected into the interior of the space using light shelves at the building’s perimeter or light tubes from the roof. Daylighting can reduce the overall lighting energy consumption and provide a visually stimulating and productive environment for occupants.

Bundles: Optimizing Daylighting Optimizing Daylighting

System Relationships

General Lighting

General lighting is the broad distribution of lighting in a space. General lighting selection should be driven by efficiency, lamp life, color quality of the light, and its intended use with a combination of direct (downward) and indirect (upward) light sources. The ceiling layout impacts the effectiveness of a general lighting scheme. Use a non-uniform lighting layout to give more visual stimulation and appeal, supplemented with task lighting providing high illumination on the worker’s task. General lighting system components are lamps, fixtures (reflectors, diffusers, and lens), ballasts, and controls. Using fluorescent, High-intensity Discharge (HID), and/or Light emitting Diode (LED) lamps, coupled with effective fixtures, can reduce energy consumption. Consider the ceiling, floor, and wall surface reflectance values to maximize light levels. Search the SF Tool for more on lighting.

Bundles: Economic Lighting Upgrade

System Relationships

Accent Lighting

Accent lighting is directional and used to emphasize an object, display item, or wash a wall. Selective illumination, often located in entrance and lobby areas, can improve brightness, create dramatic effects, and highlight points of visual interest. Couple accent lighting applications with lighting controls to ensure highlighted objects are illuminated only when occupants are nearby.

System Relationships

Entrance/Lobby lighting

Entrance and lobby lighting serves as a greeting while helping to create the individual’s initial impression upon entering the space. Entrance lighting should appear warm and inviting, bringing attention to the entryway and associated important signage. Create an effective accent lighting strategy utilizing high-efficiency lamps that decorate the space only as needed. For high-ceiling applications where bulb replacement is particularly challenging, consider long-life LED lighting strategies to minimize maintenance cost.

System Relationships