avel from one building to the other, such as
unprotected belt and shaft holes. That a fire door may be effective, it
must be hung to the only opening in the wall.

The greatest care must be exercised to keep joists from extending too far
into the wall, so as not to touch the joists of the adjacent building,
which would transmit the flames from one building to the other in case of
fire. A good stone sill should be placed under the door, and the floor
thereby entirely cut. Sills should be raised about one and a half inches
above the level of the floor, in order to accomplish the necessary
flooding of the same. If stock must be wheeled from one building to the
other, the sill can be readily beveled on both sides of the wall,
allowing the wheels to pass readily over it. Lintels should consist of
good brick arches. When swing doors are used, they should be hung on good
iron staples, well walled into the masonry, and the staples so arranged
that the door will have a tendency to close by its own weight. The door
should consist of two layers of good one and a quarter inch boards,
nailed crosswise, well nailed together and braced, and then covered with
sheet iron nailed on, or if of sheet tin, flanged, soldered, and nailed.
Particular care should be taken to insert plenty of nails, not only along
the edge of the door, but crosswise in all directions. I have seen cases,
where the entire covering had been ripped off through the warping
tendencies of the sheet iron.

The hinges on these doors should be good strap hinges, tightly fastened
to the door by bolts extending through it, and secured by nuts on the
other side. Good latches which keep the door in position when closed
should always be provided. In no case should the door be provided with a
spring lock which cannot be freely opened, as employes might thereby be
confined in a burning room.

Sliding doors should be hung on wrought iron runways, fastened tightly to
the wall. Wooden runways iron lined, which we frequently see, are not
good, as the charring of the wood in the interior causes them to weaken
and the doors to drop. Runways should be on an incline, so that the door
when not held open will close itself. Care must be taken to have a stop
provided in the runway, so that the doors may not, as I have frequently
seen them, overrun the opening which it is to protect. Doors should
overlap the edges of the openings on all sides. Large projecting jambs
should never be used.