Noise
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Overview
The conditions of the surroundings in which a tool or piece of equipment is
used to perform a task can have a significant impact on the employee's ability
to perform that task. We will consider two such factors --- noise and lighting.
Noise can be very distracting and prevent concentrated mental work. In extreme
cases, it can also result in physical disorders.
Noise can be characterized in two ways, direct and indirect. A direct noise
is determined by the intensity of the source and the distance from the ears.
Reflected noise is dependent on the reflection factors of the floor, walls,
ceiling, etc., and on the position of these surfaces.
Direct noise should be suppressed by placing covers over impact printers
or by isolating sources of noise from the rest of the work area.
A distinction should also be made between meaningful noise and general background
noise. Most working environments will have some background noise. However,
this noise can become uncomfortable if an irregularity, such as a malfunctioning
machine, develops.
Reflected noise can be reduced by introducing sound absorbing materials into
the environment. Often the actual source of noise and/or the technique for
controlling it is not readily apparent. In such instances, experts should be
consulted.
As workstations continue to migrate from the computer room to the quiet office,
acoustical noise becomes an increasingly important concern to both users and
designers alike. Acoustical noise is considered a human factor because it affects
such factors as a workers comfort, job satisfaction and performance. Noise
has several adverse effects on human beings. On the physiological side, these
effects include hearing damage and hearing loss. On the psychological side,
they include interference with speech communication, impairment of performance,
and annoyance.
Fortunately, however, the noise levels of modern workstations designed for
office or laboratory environments are relatively low, much lower than those
of typical data processing equipment found in computer room installations.
The noise is generated primarily by the single small fan in the system unit
used to cool the electronics or by the spinning hard disk drive. Displays are
usually cooled by convection and are very quiet. Workstation noise levels are
not high enough to cause hearing damage, and only seldom does the noise from
a workstation cause problems with communication or impair performance.
Thus, the primary concern from a human factors point of view is that the
noise from a workstation may be disrupting and annoying. The noise is not very
loud, but it may be reported as objectionable by the user simply because the
office environment itself is so quiet. Annoyance is a subjective response and
difficult to quantify, but it should not be treated lightly. From an employer's
point of view, an annoyed employee can present morale problems which may affect
performance and reliability.
Noise control engineers are striving to lower noise levels of workstations,
while at the same time studying and identifying the psychoacoustical aspects
of particular noises that most contribute to annoyance.
The following introduction to some relevant aspects of acoustics may help
to put the area of workstation noise into perspective.
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