Fire Prevention and Fire Extinction Part 12

_Three Wrenches for Coupling-joints._--These are for tightening the coupling-joints, when that cannot be sufficiently done by hand. When the hose are all put together a man is sent along the whole line with a pair of wrenches to tighten such of the coupling-joints as require it. The wrenches are generally made with a hole to fit the k.n.o.b on the coupling-joint, and, when used, are placed, one on the n.o.b of the male and another on the n.o.b of the female-screw, so as to pull them in opposite directions.

_Two Branch Pipes._--These are taper copper tubes, having a female-screw at one end to fit the coupling-joints of the hose, and a male-screw at the other to receive the jet pipes, one is 4 feet long to use from the outside of a house on fire, the other 12 inches for inside work.

_Three Jet-pipes_ or nozzles of various sizes made to screw on the end of the branch pipe.

A great many different shapes of jet have been tried, and that shown in Fig. 5, I found to answer best when tried with other forms. The old jet was a continuation in a straight line of the taper of the branch, from the size of the hose-screw, to the end of the jet-pipe; this had many inconveniences; the size of the jet could not be increased without making the jet-pipe nearly parallel. As the branches were sometimes 7 feet or 8 feet long, in some instances the orifice at the end of the jet-pipe was larger than that at the end of the branch. The present form of the jet completely obviates this difficulty, as the end of the branch is always 1-1/2 inches diameter.

[Ill.u.s.tration: FIG. 5.]

The curve of the nozzle of the present jet is determined by its own size; five times one-half of the difference between the jet to be made and the end of the branch, is set up on each side of the diameter of the upper end of the branch, a straight line is then drawn across, and an arc of a circle described on this line, from the extremity of each end of the diameter of the jet, until it meets the top of the branch; the jet is then continued parallel, the length of its own diameter; the metal is continued one-eighth of an inch above this, to allow of a hollow being turned out to protect the edge: The rule for determining the size of the jet for inside work is, to "make the diameter of the jet one-eighth of an inch for every inch in the diameter of the cylinder, for each 8 inches of stroke." The branch used in this case is the same size as shown in Fig. 5. When it is necessary to throw the water to a greater height, or distance, a jet one-seventh less in area is used, with a branch from 4 feet to 5 feet long.

_Two Lengths of Scaling Ladders._--These are 6-1/2 feet long, and are fitted with sockets so that any number up to 7 or 8 may be joined together to form one ladder varying in length according to circ.u.mstances from 6-1/2 to upwards of 40 feet.

_One Fire-hook._--This is similar to a common boat-hook, of such length as may be most convenient to strap on the handles of the engine. It is used for pulling down ceilings, and taking out deafening-boards when the fire happens to be between the ceiling and the floor above. It is also used when a strong door is to be broken open. It is placed with the point upon the door, one or two men bearing upon it, while another striking the door, the whole force of the blows is made to fall upon the lock or other fastening, which generally yields without much difficulty.

_Sixty Feet of Patent Line and Twenty Feet of Trace Line._--These are generally used for hoisting the hose into the windows of the house, in which there is a fire, the stairs being sometimes so crowded with people and furniture, that it is difficult to force a pa.s.sage, and when the pipe is laid in the stair, it is liable to be damaged by people treading on it.

_One Mattock and Shovel._--These are useful in damming any running water or gutter, uncovering drains, &c., from which the engine may be supplied with water. The mattock should be short and strong, and the shovel of the sort called diamond-pointed.

_One Hatchet._--The most serviceable hatchet for a fire-engine, is similar to that used as a felling axe by wood-cutters. The back part is made large that it may be conveniently used as a hammer.

_One Saw._--This should be a stout cross-cut saw, very widely set. It is useful in cutting off the communication between one house and another, which, when water is scarce, is sometimes necessary.

_One Iron Crow-bar._--This should be about two feet long. It is used in opening doors, breaking through walls, &c.

_One Portable Cistern._[P]--This is made of canvas on a folding iron frame, and is used in London placed over the street-fire plugs, a hole is left in the bottom through which the water enters and fills the cistern, the escape between the canvas and the plug box being trifling. Two and sometimes three engines are worked by suction-pipe from one plug in this manner. The portable cistern is also used when the engine is supplied by suction, from water conveyed in carts or buckets, and is greatly preferable to any plan of emptying the water directly into the engine. By this latter method there is always a considerable waste of water, arising both from the height of the engine, and the working of the handles; and, in addition to these objections only one person can pour in water at a time. When the water is poured into the engine from carts, it must stop working till the cart is emptied. All these objections, are in a great measure removed by placing the portable cistern clear of the engine; when used in this manner there must of course be no hole in the bottom.

_One Flat Suction Strainer_, made to screw on to the suction pipe, to prevent anything being drawn in that would not pa.s.s through the jet-pipe, and made flat, with no holes in the upper surface, for use in the portable cistern.

_One Standc.o.c.k_, with stem to insert direct in the fire-plug, and used princ.i.p.ally with hose to throw a jet for cooling ruins.

_One Canvas Sheet._--This, when stretched out and held securely by several men, may be jumped into from the window of a house on fire with comparative safety.

_One Hand-pump_, as described at page 130, and used with the canvas buckets.

FOOTNOTES:

[Footnote G: The engines and their crews are distinguished by these colours.]

[Footnote H: The hose are made up in flat coils, with the male coupling-screw in the centre, and the female on the outside. When a length is to be laid out in any direction, it is set on its edge, and then run out in the required direction,--in this way no turns or twists can ever occur. When the hose is to be taken up, it is uncoupled, and then wound up, beginning at the end farthest from the engine or from the fire-c.o.c.k (as the case may be): by this method all the water is pressed out.]

[Footnote I: In practising this exercise the men are in the habit of descending by the chains from the parapet of the North Bridge, Edinburgh, to the ground below: a height of 75 feet.]

[Footnote J: Mr. Braidwood used canvas jumping sheets on this principle with hand holes for a dozen men, in the ordinary service of the London Fire Brigade.]

[Footnote K: Now Shand, Mason, and Co.]

[Footnote L: This description applies to the most recently constructed fire-engines belonging to the Metropolitan Fire Brigade.]

[Footnote M: "Stuffing," a technical term need by leather-dressers or curriers.]

[Footnote N: The proportions are, 1 gallon neats-foot oil, 2 lbs.

tallow, 1/4 lb. bees-wax, melted together, and laid while warm on the leather.]

[Footnote O: This description of the Edinburgh coupling-joints was written in 1830, and is inserted here to show how the present form of the well-known London Brigade hose-coupling was arrived at. The internal diameter was originally 2-3/8 inches, but Mr. Braidwood, when in London, found that he could increase it to 2-1/2 inches.]

[Footnote P: See engraving of portable cistern, page 156.]

FIRE ANNIHILATOR

With regard to the Fire Annihilator, I have seen several experiments with this machine, and heard of more which were not successful; and if an invention fails when experiments are tried, it is open to the impression that it might fail when brought into active operation.

There have also been many cases where these machines have met with accidents, one at Drury Lane Theatre amongst the number.

Water, properly applied, will do whatever the Annihilator can accomplish, and also many things which the latter cannot do. As it is, there are some forty or fifty different articles to carry with each fire-engine, and to add to them such unwieldy things as Fire Annihilators, would be to enc.u.mber the men more than they are at present, with a very doubtful prospect of advantage.

WATER SUPPLY.

The supply of water is the most vital part of any exertions towards extinguis.h.i.+ng fire. Where the pressure is sufficient, and the mains large enough, by far the most efficient and economical mode of using the water is to attach the hose directly to the mains.

In London, however, this can rarely be done, for several reasons. The greatest number of plugs are on the service pipes, that is, the pipes for supplying water for domestic and other purposes, which are only open a short time every day. If the cisterns are nearly empty, the pressure cannot be obtained till they are filled. Then, again, the plugs being some distance apart, it is difficult to obtain a sufficient number of jets. But when the plugs are full open 1-3/4 diameter, a sufficient quant.i.ty of water is obtained from each to supply three engines, each of which will give a jet equal to the plug if confined to one jet. The pressure also in the mains in London seldom exceeds 120 feet at the utmost. For these reasons the pressure from the mains is seldom used till the fire is checked, when the ruins are cooled by the "dummies," as the jets from the mains are named by the firemen.

If water can be obtained at an elevation, pipes with plugs or firec.o.c.ks on them, are preferable to any other mode at present in use for the supply of fire-engines. The size of the pipes will depend on the distance and elevation of the head, and also on the size of the buildings to be protected. It may be a.s.sumed as a general rule, that the intensity of a fire depends, in a great measure, on the cubic content of the building; distinction being made as to the nature and contents of such building. If no natural elevation of water can be made available, and the premises are of much value, it may be found advisable to erect elevated tanks; where this is done, the quant.i.ty of water to be kept ready, and the rate at which it is delivered, must depend on the means possessed of making use of the water.

The average size of fire-engines may be taken at two cylinders of 7 inches diameter, with a length of stroke of 8 inches, making forty strokes each per minute. This sized engine will throw 141 tons of water in six hours, and allowing one-fourth for waste, 176 tons would be a fair provision in the tanks for six hours' work; this quant.i.ty multiplied by the number of engines within reach, will give an idea of what is likely to be required at a large fire. If, however, there are steam-engines to keep up the supply through the mains, the quant.i.ty of water kept in readiness may be reduced to two hours' consumption, as it is likely that the steam-engines would be at work before that quant.i.ty was exhausted. This is what may be supposed to be required, in cases of serious fires in dockyards, in large stacks of warehouses, or in large manufactories.

[Ill.u.s.tration: FIG 6. Opening for Suction-pipe.]

Where water can be had at nearly the level of the premises, such as from rivers, ca.n.a.ls, &c., if it is not thought prudent to erect elevated tanks, the water may be conducted under the surface by large cast-iron pipes, with openings at such distances as may seem advisable for introducing the suction-pipes (Fig. 6). This plan should not be adopted where the level of the water is more than 12 feet below the surface of the ground, as although a fire-engine will, if perfectly tight, draw from a much greater depth than 14 feet (2 feet being allowed for the height of the engine), still a very trifling leakage will render it useless for the time, at such a depth.

The worst mode of supplying engines with water is by covered sunk tanks; they are generally too small, and unless very numerous, confine the engines to one or two particular spots, obliging the firemen to increase the length of the hose which materially diminishes the effect of the fire-engine. If the tank is supplied by mains from a reservoir, it would be much better to save the expense of the tank, and to place plugs or firec.o.c.ks on the water-pipe. Another evil in sunk tanks is, that the firemen can seldom guess what quant.i.ty of water they may depend upon, and they may thus be induced to attempt to stop a fire, at a point they would not have thought of if they had known correctly the quant.i.ty of water in store.

Where sunk tanks are already constructed, they may be rendered more available by a partial use of the method shown in Fig. 6.

_Memoranda of Experiments tried on the mains and service pipes of the Southwark Water Company, between 4 and 9_ A.M. _of the 31st January, 1844. The wind blowing fresh from N.N.W._

The pressure at the water-works at Battersea was kept at 120 feet during the experiments, and every service pipe or other outlet was kept shut.

_1st Experiment._--Six standc.o.c.ks, with one length of 2-1/2 inches riveted leather hose 40 feet long, and one copper branch 4 feet to 5 feet long, with a jet 7/8 inch in diameter on each, were placed in six plugs on a main 7 inches diameter, in Union-street, between High-Street, Borough, and Gravel-lane, Southwark, at distances of about 120 yards apart. The water was brought from the head at Battersea, by 4250 yards of iron pipes 20 inches diameter, 550 yards of 15 inches diameter, and 500 yards of 9 inches diameter.

1st. One standc.o.c.k was opened, which gave a jet of 50 feet in height, and delivered 100 gallons per minute.

With four lengths of hose the jet was 40 feet high, and the delivery 92 gallons per minute. When the branch and jet were taken off with one length of hose the delivery was 260 gallons per minute.

2nd. The second standc.o.c.k was then opened, and the jet from the first was 45 feet high.