=12. Location of Shaft.=—In all factories of two or more stories, an
elevator is a necessity for the economic transmission of goods from
one floor to another. While in some instances the elevator is run
through hatch openings in the floor, without being enclosed in brick
walls, it is not good practice, for the openings through the floors
make possible the rapid communication of flames and smoke in case of
fire, even when provided with an automatic closing hatch. Elevators are
therefore generally built in an elevator shaft, the walls of which are
constructed of good hard brick and made from 12 inches to 18 inches in
thickness.
=13. Elevator Doors and Openings.=—In building elevator shafts, it is
necessary to provide door openings at each floor, the openings being
protected with tin-lined fireproof doors. These doors may be either
folding or sliding-doors, it usually being considered best to provide a
sliding-door that will automatically close when a certain temperature
has been reached in the building. It is not always possible, however,
to provide sliding-doors, from the fact that where the elevator shaft
projects out into the room and the door opening is wide, there is no
wall space on which to fasten the track. Customarily, in each door
opening, there is also provided a heavy stone or cast-iron sill. As in
many states the law requires some automatic, or folding, lift gates
for elevator openings, it is the practice to project this sill inside
of the shaft at least 4 inches, in order to provide a bearing and
protection for such gates.
=14. Construction of Openings.=—The openings in the brick walls of an
elevator shaft are constructed ordinarily with rowlock brick arches,
and from the fact that the openings are usually wide, and little jamb
is left on each side of the opening, it is necessary to build 1-inch
round iron rods in the arch above the opening, these tie-rods being
furnished with washer plates at each end.
The jambs of all openings in the elevator shafts should be protected
with cast-iron fenders made of about ½-inch metal, and so constructed
as to return about 4 inches on each face. These jambs are provided with
heavy wrought-iron anchors, which are built into the brickwork in the
process of construction.
[Illustration: (_a_)]
[Illustration: (_b_)