Ergonomics - Atlas Copco

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Temperature
Hand-held power tools often contain heat
or cold sources which affect the tempera-
ture of their surfaces. Contact with these
surfaces may cause the tool operator
discomfort, pain and even injury. Thus,
it is the responsibility of the tool designer
to keep the temperature of the surface of
the hand tool within limits that will not
affect the health of the operator.
A relatively large amount of research has
been done on the physiological responses of
the human being exposed to hot surfaces.
Standards and guidelines concerning
acceptable limits for hot surfaces (e.g., the
European standard EN 563: 1994; and the
publication of the British Standards Insti-
tute, PD 6504: 1983) are available based on
these studies.
However, scientific research on the
physiological responses of human beings
to cold surfaces is rare. Limited data from
some individual studies may provide guide-
lines for designers constructing a hand-held
power tool with cold surfaces.
Factors influencing
temperature limits
The following factors may influence tolerable
temperature limits:
l Surface temperature, i.e., the temperature
of a handle surface measured on the
Celsius scale;
l Contact period, i.e., the period of time during
which contact with the surface takes place;
l Thermal inertia, i.e., the combined effect of
the density, thermal conductivity and spe-
cific thermal capacity of the material used in
the construction of the tool. (A list of thermal
inertia for some common materials is given
in Table 3.11.)
l Material properties of the surface; i.e., the
chemical/physical composition of the mate-
rial and the characteristics (rough, smooth)
and shape of the surface.