Interior Lighting for Designers

(Elliott) #1

  1. The optimum distance away from the wall
    and on-center spacing.

  2. The mounting cavity height, depth, and
    finishes required.

  3. The necessity of baffles to shield the
    lamps from view along the length of the
    cavity.
    A full-size mock-up is the only way to
    ensure that the finished installation will
    achieve the desired illuminance value and
    avoid scallops and striations at the top of the
    wall. No miniature light sources exist to test
    the performance of architectural lamps in a
    scale model.


Continuous, linear, diffuse-source
wall-wash. The diffuse fluorescent source is
good at providing even lighting across the wall
in the horizontal direction but is inadequate at
providing even illuminance vertically from top
to bottom. Reflectors help to mitigate the
problem but fail to solve it for walls exceeding
10 ft in height. The use of a fluorescent wall-
wash system is reserved for low ceiling areas
with wall heights from 8 to 10 ft.


Specular vertical surfaces
When providing light for glossy surfaces,
such as glass, marble, high-gloss enamels,
and varnishes, specular reflections compli-
cate the placement of lighting equipment.
Careful location and shielding of the source
prevents distracting reflections and veiling
images.
Think of the glossy surface as a mirror;
eliminate glare by minimizing high luminance
in the reflected field of view. To reduce
reflected images, remove bright elements in
the reflected field of view or shield them with
properly located baffles or screens.
People, objects, and other surfaces in
the room become secondary light sources. If
they are located in the reflected field of view,


they will cause distracting or veiling reflec-
tions in glossy surfaces. In some cases, the
perception of varnished or glass-covered
paintings, or of marble and other specular
materials, is partially or completely obscured
by such reflected images.

Task Lighting


Lighting systems in the workplace provide for
accurate perception at a specific task area
(a desk, counter, machine, or workbench).
This is achieved by using one of two lighting
methods: a general-ambient approach or a
task-ambient approach.
General-ambientsystems provide a uni-
form quantity of light throughout a space.
This approach is often used when the task
location is apt to vary widely or when the
space will be reconfigured frequently.
Task-ambientsystems are more energy-
effective. Higher values of task illuminance
are provided for the workplane while lower
values of ambient illuminance are provided
for surrounding areas.
Task-ambient systems are appropriate
in rooms where task areas are permanently
located, such as private offices, factories,
laboratories, and stores. Task lighting is pro-
vided for task areas, with the remaining
space lighted for more casual activities
(figure 13.12).
When designing a task-ambient system,
first light the task (focal glow), then supple-
ment the task lighting with ambient room
lighting. In typical task-ambient systems,
task-oriented luminaires are mounted on or
near the furniture and supplemented by an
ambient (uniform) lighting system that pro-
vides lower illuminance.
Ambient lighting provides overall illumi-
nation for circulation, provides balance
between the VDT task luminance and its sur-
round, and provides part of the illuminance
for paper-based tasks. Areas surrounding
visual tasks need less illuminance than the

INTERIOR LIGHTING FOR DESIGNERS

Free download pdf