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

STANDARD CAR 457
The studies already reported in Bulletin No. 17 had shown the desirability
of the basket bunker. To this we asked the roads to add
an insulated, solid, bulkhead, open top and bottom for air inlet and
outlet. We had found such a bulkhead to be an essential in maintain-
ing air circulation in small, ice cooled chill rooms designed especially
for dressed poultry and eggs with bunkers of either the overhead or
the upright type, and had worked out the details of the construction
in such rooms. We also asked for cars containing varying amounts
of <strong>insulation</strong> and we suggested that it be installed with and without
air spaces.
By the early spring of 1916 we had ready quite a number of
experimental cars built by four roads in as many shops. The details
of construction varied widely. This we considered advisable because
we first had to establish the fundamentals of construction, such as
the type of bunker and the action of floor racks, regardless of the
sfze or particular desirability of the car itself. In every case the
principle of one variable, only, was maintained, hence the cars were
built and used in series. For example, in order to test the bunker,
of the basket type with solid insulated bulkhead, such a car had for
comparison another, built at the same time and identical in every
respect except that it was provided with a box bunker and an open
bulkhead. To reduce the information to still simpler terms, a third
car had a box bunker with an insulated bulkhead, and a fourth car
had a basket bunker with an uninsulated bulkhead. When this series
was loaded with the same commodity and run in the same train to
the same destination, with resistance thermometer equipment as pre-
viously described, variations in temperature could be referred with a
fair degree of certainty to the one variation in construction.
A similar series was used to determine the relative value of the
floor rack and also the details of its construction, such as height,
width of slats and width of space between the slats. The <strong>insulation</strong>
series contained cars having one, two and three inches, respectively,
of hair felt, flaxlinum and linofelt. In order to determine the points
of heavy strain on the <strong>insulation</strong> roofs, floors and walls were given
unequal amounts.
Of course, these experimental cars were not all built at once,
and, as we were in close co-operation with the shop superintendents,
the facts, as gleaned, were at once incorporated into the building.
To go into the details of the many experiments, with various
products, in various parts of the country and under varied weather
conditions, will be a lengthy task even for a government bulletin.
What concerns us here are the broad facts and the deductions which
have been drawn from them, especially those concerning air circulation
and the amount and distribution of <strong>insulation</strong>. Let us begin
with air circulation.
It did not take long to decide that the basket bunker, insulated
bulkhead and a rack four inches ofif the floor, with lengthwise string-