2.6 Daylighting Related Design Issues - Interior
The following guidelines, adapted from "Tips for Daylighting" from Lawrence Berkeley
National Laboratories, can help make a daylighting design more effective:
- Locate activities according to light requirements. Put rooms with
little need for daylight or with infrequent use, such as service or washrooms or
high use of audio-visual or video display (VDT) equipment in non-perimeter areas.
Locate tasks with higher lighting needs nearer the windows. Group tasks by similar
lighting requirements for efficient use of electric lighting, and by similar schedules
and comfort needs.
- Locate activities according to comfort requirements. Place flexible
tasks or low occupancy spaces where there may be unavoidable glare, not enough daylight,
or direct sun penetration. These spaces may at times be thermally or visually uncomfortable.
If tasks are fixed and inflexible, comfortable glare-free conditions are required.
- Maintain daylight access. Furniture layout should not block light
for spaces farther from the window. Do not position full-height partitions, bookshelves,
or files parallel to a window wall if possible.
- Use light-transmitting materials for partitions where possible.
Use clear or translucent materials in the upper portion of full-height partitions.
If this approach is taken in corridor walls, corridors may be adequately lighted
just by this spill light.
- Shield occupants from views of highly reflective surfaces outside,
such as mirrored-glass buildings, water, snow, and large white surfaces.
- Shield sensitive occupants from bright windows. In highly glare-sensitive
areas (e.g., with wide use of VDTs), shield occupants from view of sky and provide
glare-controlling window coverings.
- Keep reflected view of bright windows out of computer screens.
Be very careful where VDTs are placed. Either keep them away from windows or block
the screen and occupant's view of the window. Use partitions or position the screen
with the window to the side and slightly turned away from the window.
- Use west zones for service spaces. Minimize use of exposed west
zones as occupied work areas. Large areas of west glazing make for difficult daylighting,
high cooling loads, and uncomfortable occupants.
Overhead skylights Source: Benya Lighting Design
- Don't use large areas of dark color. Generally avoid all dark colors
except as accents, and keep them away from windows. Dark surfaces impede daylight
penetration and cause glare when seen beside bright surfaces. For good distribution
throughout the room, it is especially important that the wall facing the window
be light-colored. Mullions or other solid objects next to windows should be light-colored
to avoid silhouette contrasts. Keep sills and other reveal surfaces light to improve
daylight distribution and soften contrast. Dark artwork can reduce daylight effectiveness.
- Aim for recommended surface reflectances. The Illuminating Engineering
Society recommends the following reflectances: ceilings >80%; walls 50-70% (higher
if wall contains window); floors 20-40%; furniture 25-45%.
- Choose matte over specular surface finishes. Matte finishes are
recommended for good distribution of daylight and no reflected glare (hot spots).
- Use light-transmitting materials. Translucent or transparent partitions
are best when possible-daylight can pass through to other spaces.
- Supply window coverings that allow individual control to accommodate
different glare tolerances. Interior window shading should be light-colored for
best cooling load reduction.
- Choose colors under the right light. Choose interior colors and
finishes under daylight and under the proposed electric lamps to avoid surprises
in color rendering.