12-10-2012, 01:26 PM
LIGHTING DESIGN – GENERAL INDUSTRIAL APPLICATIONS
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The purpose of industrial lighting is to provide energy efficient illumination
in quality and quantity sufficient for safety and to enhance visibility and productivity
within a pleasant environment.
Industry encompasses seeing tasks, operating conditions and economic
considerations for a wide range. Visual tasks may be extremely small or
very large; dark or light; opaque, transparent or translucent; on specular or
diffuse surfaces and may involve flat or contoured shapes. With each of the
various task conditions, lighting must be suitable for adequate visibility and
productivity in developing raw materials into finished products. Physical
hazards exist in manufacturing processes and, therefore, lighting must contribute
to the utmost as a safety factor in preventing accidents. The speed
of operations may be such as to allow only minimum time for visual perception
and, therefore, lighting must be a compensating factor to increase
the speed of vision.
Lighting must serve not only as a production tool and as a safety factor, but
should also contribute to the overall environmental conditions of the work
space. The lighting system should be part of an overall planned environment.
GENERAL CONSIDERATIONS OF DESIGN FOR LIGHTING
INDUSTRIAL AREAS
The designer of an industrial lighting system should consider the following
factors as the first and all-important requirements of good planning.
1. Determine the quantity and quality of illumination desirable for safety of
personnel (see page 136), the manufacturing processes and the environment.
2. Select lighting equipment that will provide the quantity and quality
requirements by examining photometric characteristics, and mechanical
performance that will meet installation, operating and actual maintenance
conditions.
3. Select and arrange equipment so that it will be easy and practical to
maintain.
4. Balance all of the energy management considerations discussed in
Section 4 and economic factors including initial, operating and maintenance
costs, versus the quantity and quality requirements for optimum
visual performance. The choice of the electric distribution system may
affect overall economics.
Although not specifically mentioned in the discussions of the lighting for
each industry that follow, the use of daylighting should be considered for
area lighting in all industries.
SUPPLEMENTARY
LIGHTING IN INDUSTRY
Difficult seeing tasks often require a specific, amount or quality of lighting
which cannot readily be obtained by general lighting methods. To solve
such problems supplementary luminaires often are used to provide higher
illuminances for small or restricted areas. Also, they are used to furnish a
certain luminance, or color, or to permit special aiming or positioning of
light sources to produce or avoid highlights or shadows to best portray the
details of the task.
Because supplementary lighting can be specified, it is necessary to recognize the
exact nature of the visual task and to understand its light reflecting or transmitting
characteristics. An improvement in the visibility of the task will depend upon one
or more of the four fundamental visibility factors — luminance, contrast, size and
time. Thus, in analyzing the problem, the designer of the lighting may find that seeing
difficulty is caused by insufficient luminance, poor contrast (veiling reflections),
small size, or that task motion is too fast for existing seeing conditions.
The planning of supplementary lighting also entails consideration of the visual
comfort of both those workers who benefit directly and those who are in the
immediate area. Supplementary equipment must be carefully shielded to prevent
glare for the user and his associates. Luminance ratios should be carefully
controlled. Ratios between task and immediate surroundings should be limited.
To attain these limits it is necessary to coordinate the design of supplementary
and general lighting.