(The castings are placed in the cabinets and are held and turned about
by the operators, who watch the progress of the work through glass
panels. The dust is carried off through the exhaust ducts.)]
Illumination.
The average foundry is poorly lighted, and many accidents may be
attributed directly to this condition. There are many problems to be
considered in providing proper and adequate light for foundries, and as
the conditions that have to be met vary a great deal, it is impossible
to make any general recommendations that will be applicable in all
cases.
The floors, walls, supporting columns, ceilings, and materials in
foundries are usually covered with grime and dust which absorb from 95
to 98 per cent. of the light that strikes them, and which give them
all the same general tone or color. With no contrasting background
it becomes exceedingly difficult, at times, to distinguish objects
lying upon the floor, and care should therefore be taken to see that
the floor is kept free from tools, materials, and obstacles of every
other kind, over which the workmen might stumble. Moreover, if the
ventilating system is inadequate to keep the air reasonably clear,
the dust, smoke, and gases will not only reduce the intensity of the
illumination and thereby invite accidents, but may also affect the
health of the working force.
During certain stages of the work,--notably at pouring time,--the men
are exposed to a dazzling, blinding radiation from the white-hot,
molten metal. Very often, too, lighting units of intense intrinsic
brilliance and high candle-power are placed where they shine directly
into the eyes of the men. Conditions such as these impair the vision
of the worker, thereby reducing his efficiency as a producer, and
multiplying the opportunities for accidents.
One of the best artificial lighting sources for foundry work is the
Mazda C lamp (500 to 1,000 watt sizes). To determine the proper
location of the lamps, and their spacing, suspension heights, and other
features (such as the types of reflectors that should be used) it is
necessary to understand, as fully as possible, the exact conditions
that must be met. Where incandescent lighting units are to be used,
wall brackets, fitted with angle reflectors, provide the best means of
securing satisfactory illumination at the floor level. Good results may
be obtained by installing the brackets on the supporting columns, under
the crane runway and below the smoky zone.
Although we have spoken only of artificial light for foundries, it is
important to admit the greatest possible amount of natural light. As
a usual thing, skylights are of little value on account of the clouds
of smoke that often fill the upper part of the building, and therefore
practically all the natural light that can be really serviceable
must pass through windows in the side walls. For the same reason the
effective window area must be considered as only that below a height of
approximately twelve feet. It is essential that the windows occupy as
much of the wall space as possible, and, where the width of the room
is great, prism glass should be used. Prism glass, when properly set,
will reflect the light into the room in a nearly horizontal direction.
Satisfactory natural illumination can hardly be had without keeping
the windows clean; and we also strongly advise whitewashing the walls,
ceilings, and supporting columns, applying fresh coats whenever they
are needed.
[Illustration:
_Courtesy of American Blower Company._