_The Necessity for Safeguards_
The majority of small houses will be built of either wood-frame
construction or of wood-and-masonry construction for many years to
come, in spite of the propaganda favoring fireproof dwellings, for the
cost of materials and labor are so adjusted that houses of this better
type cannot be built by the average citizen. In fact, 90 per cent of
the houses erected to-day use wooden studs and floor beams.
This method of building costs the fire insurance companies about
$60,000,000 a year. The actual loss must be even greater than this, for
not all houses are insured.
We might as well face these facts frankly and accept the next best
means of preventing this enormous annual loss of dwellings by
establishing safeguards against this fire dragon at the most vulnerable
parts of the building. We must place the armor of protection where
it is needed most, and set up the safeguards against fire where the
dangerous enemy attacks.
On examination of the insurance reports upon this question, we find
that 96 per cent of all the fires originate inside of the houses. The
most important cause of these fires is defective chimney construction.
Bad fireplace design, careless flue construction, and poor masonry work
in the chimney are responsible for many a tragic fire and a total loss
of furniture, clothes, and household goods of well-meaning citizens. It
is true that this is a cause of fire which may be prevented by building
good chimneys and fireplaces, but there are other causes that are not
so easily regulated, such as explosions from kerosene, short circuits
in the electric iron or vacuum cleaner, careless throwing around of
burned matches and cigarettes, and many other accidents which are bound
to occur in spite of all precautions. When such fires start, there is
only one thing to do: extinguish them in the quickest possible manner.
But this cannot be done easily if the walls and the floors of the house
are so built that they act as hidden passages and flues for the flames
to creep insidiously throughout the building, breaking out in the most
unexpected places and entrapping the unwary in dangerous positions. The
way that many dwellings are constructed makes it possible for a fire
to start in the cellar over the smoke-pipe from the furnace, in the
dead of night, creep silently through the floors and up the interior
partitions to the attic and second floor, until suddenly, bursting
forth in all its fury, it has the sleeping inhabitants ensnared in a
box of fire that has cut off their escape. The terrible heat has eaten
away the strength of the bearing partitions, the floors collapse, the
stairs are encircled with a writhing flame, and smoke and fire issue
from everywhere as suddenly as though they had been spontaneously
produced. There is no time to fight such a fire as this; about all
that can be done is to escape in safety, and then the history of such
conflagrations tells of the tragic death of many children left behind
in the excitement.
It is this fearful danger of the secret entrapping of fire that it is
possible to eliminate from the wooden house. At least we can make this
demon element come out into the open, where we can see to fight him. We
can set safeguards against his passage through floors and walls,
up stairs, and behind wainscots. In most cases where houses are so
protected a fire can be quickly extinguished by the fire department or
by a chemical fire-extinguisher kept in the house.
This business of setting up fire-stops when the house is being
constructed should be known. The closing of the passage between the
plaster, furring strips, and masonry wall, the blocking of continuous
ways through exterior stud walls and interior bearing partitions, the
filling in of the hollow spaces behind wainscots, the protecting of the
under side of stairs, and many other precautions can be provided for in
the plans and specifications without adding much to the expense.
_Placing of the Fire-Stops_
There are two general places where these fire-stops should be
constructed: in the vertical walls to cut off concealed drafts and in
the horizontal floors to act as barriers between one floor and the
next. A fire which starts in the cellar can be confined for some time
from spreading upward if the ceiling is covered with metal lath and
plaster and all the possible vertical openings in the walls are stopped
with concrete, mineral wool, or other effective material. On the other
hand, a fire which starts in the attic may spread to the lower stories
by sparks dropping down inside of the partitions, unless they are
properly fire-stopped.
It is very important, however, to have fire-stops carefully built,
for when gas is heated to the temperature of combustion it will pass
through very small crevices, setting fire to the materials on the other
side. It only requires a temperature of 1000° F. to ignite wood, and if
the air is this hot, although it may appear harmless, it will set
fire to whatever combustible material it touches. For this reason,
fire-stops carelessly installed are as good as none. As an example
of this, blocks of wood are sometimes used between the studs as a
fire-stopping material, but, as it requires time to fit this material
in place, small cracks are often left between the blocks and the studs,
which permit the heated gases easily to pass through them to the other
side. This is also true when bricks are used for fire-stops. As the
average stud is only about 3¾ inch wide, and the average brick is
4 inches, it is impossible to fill the space between the studs with
bricks, laid flatwise, but they must be set on edge, leaving a wide
crevice which must be filled in with mortar. This is often poorly done
or omitted entirely, making the brick fire-stop inadequate.
In enumerating the places where fire-stops should be built, the most
important ones are the blocking of the space between the plaster and
furred brick wall at each floor level and the closing of the air-space
in exterior stud walls at each floor (Figs. 1, 2, 3). The filling in
of the hollow space at the base of every interior stud partition is
likewise necessary (Fig. 4). A wooden cornice banks up the heat from
any neighboring fire, and it is advisable to fire-stop the space around
the ends of the rafters where they join with the ceiling-joists over
the plate (Fig. 5). Where the second floor of the house projects out
over the porch, it should be filled with fire-stopping material, not
only for safety against fire but also to keep out the cold in the
winter (Fig. 6). The pockets into which sliding-doors roll should
be lined with gypsum board, not only as a fire retardant but also
to prevent cold drafts from coming out of these pockets (Fig. 7).
The plaster should be carried down behind all wooden wainscots as a
fire-stop (Fig. 8). The space between the stair carriage should also
be closed at each story (Fig. 9), and all chases and ducts should
be filled at each floor level. Wherever exposed pipes pass through
horizontal parts of the house they should be run through sleeves.
Wherever hot-air flues go from one floor to the next they should be
packed around with incombustible material (Fig. 10), and all registers
in floors should be insulated in the same way. The space between
floor-joists and chimneys must also be filled in with fire-stopping
materials.
[Illustration: Fire-stopping of furred off space in brick wall