by Eric Strandberg LC, Lighting Design Lab
We've all been in corridors that never feel bright enough. Even though there are plenty of light fixtures and a window, it still feels gloomy. Here are some design strategies to over-come this problem.
Surfaces
The first area to look at is not the lighting at all, but the surfaces. What
are the colors and textures of the walls, ceiling, and floor? Are they light
and reflective or dark and absorptive? Changing surface finishes is one of
the easiest and least expensive ways to really brighten up a space. Often
a gallon of light colored paint will boost the brightness. When was the last
time the surfaces and light fixtures were cleaned? Dirty surfaces and fixtures
may absorb over 30% of your light! If you can't change the surfaces, such
as with lots of brick and natural wood, then focus on electric lighting solutions
to the problem.
130 V Lamps vs CFLs
Because they are on 24 hours a day, common area lights in apartments often
have 130 volt incandescent bulbs in the light fixtures. These are long life
bulbs, but they put out yellower and dimmer light than their 120 volt equivalent.
A good alternative is a screw in Compact Fluorescent Lamp (CFL). If your existing
luminaire will accept a CFL, the advantages of longer lamp life, lower energy
costs, less heat, and more light will be yours! The wattage of the CFL should
be no less than 1/3 of the bulb you are replacing to achieve the same light
levels (20W = 60W).
Lenses
Some fixtures have lenses that aren't very efficient at transmitting light.
Changing the lens to one with a higher light transmittance may improve brightness
but be aware that more efficient lenses for your fixtures may be difficult
to find. Also, replacing high density lenses with clearer lenses can lead
to glare problems.
Placement
In new construction (or if the above solutions aren't practical) take a look
at new luminaires and placement strategies. Ideally, the new luminaire should
have some surface brightness (translucence) but not too much or it will cause
glare. Most of the light from the new fixture should reflect indirectly from
a light colored ceiling. The luminaires should be placed by the doors, intersections,
and stairways. Don't forget to light the end walls of the corridor so that
the user is walking toward an illuminated destination. This is a good place
to have artwork for visual interest. Try using a variety of fixtures for different
tasks. Mix glowing luminaires on the wall or ceiling for general lighting
and more directed light fixtures (like track or recessed cans) on areas of
visual interest. The directed lighting might be focused on objects like artwork,
signs, mailboxes, and phones. These directed lights could be fluorescent track
spots, luminous soffits, or recessed wall washers.
Daylighting and Glare
Surprisingly, the window at the end of a hallway can create more glare than
illumination. The contrast ratio between the high intensity of daylight and
the relatively dim interior can create glare problems, even on a cloudy day.
The window image appears hundreds of times brighter than the light from the
luminaires, yet the window only gives about 15 linear feet of useful light
into the space. There are a number of ways of working through an existing
situation using drapes, awnings, and window treatments but the best solutions
incorporate architectural elements that maximize the light penetration while
minimizing the glare. Pay close attention to the reflective properties of
the floor, as shiny linoleum can really amplify the glare problem! This can
be especially difficult for senior citizens, with aging vision and visual
adaptation issues. Proper common area lighting can have a great impact on
the appearance, function, safety, and maintenance of a building and should
not be left as an afterthought.
