Cork insulation; a complete illustrated textbook on cork insulation ...

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CORKBOARD INSULATED REFRIGERATOR 341
ice manufacturers or the refrigerator manufacturers, and even
those principles worked out and established for the benefit and
guidance of the ice and refrigerating and allied industries,
and which are directly applicable to the household, often have
been overlooked, ignored or misapplied.
For instance, careful scientific research established the fact
that the flow of heat through a given insulating material was
retarded by an external or surface resistance as well as by
an internal resistance, but that its surface resistance virtually
disappeared if the surfaces of the material were no longer
in contact with the surrounding atmosphere, as elaborated in
the section of this book on "The Study of Heat." But this
scientific fact was either misunderstood, or its true significance
ignored, because many manufacturers of household refrig-
erators re-designed their product on the basis of multiple in-
sulation on the incorrect theory that each layer of material
in the walls of a refrigerator sets up or offers its own individual
surface resistance to the transfer of heat, even though
these layers are laid one against another or in positions of in-
timacy and their surfaces are not exposed to the surrounding
atmosphere. In other words, in theory, the surface resistances
of many layers of material were incorrectly combined to arrive
a wholly fictitious high total resistance of a given wall to
infiltration of heat. The claim of superiority based on
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multiple walls of <strong>insulation</strong> was a familiar one, and for too
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many years unsuspecting householders counted the
comparing prices.
layers in
With the growth of the ice industry, the refrigerator industry
expanded proportionately, and competition became
keen and difficult. Little real attention was paid to the actual
: insulating qualities of a household refrigerator ; for, as some
["have said, "the ice man wanted to sell ice, the refrigerator
' wanted
manufacturer wanted to sell refrigerators, and the householder
something low in cost and high in hopes." It is prob-
ably more to the point, however, that the real need for better
<strong>insulation</strong> in household refrigerators had never been made
clear to the ice man, the refrigerator builder, or the house-
holder. In a word, the necessity did not exist, and the need
was not understood.