The supply of water is the most vital part of any exertions towards extinguishing 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 quantity 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 firecocks 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 assumed 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 quantity 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 quantity 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 quantity 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 quantity 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.
Where water can be had at nearly the level of the premises, such as from rivers, canals, &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 firecocks on the water-pipe. Another evil in sunk tanks is, that the firemen can seldom guess what quantity 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 quantity 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 standcocks, 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 standcock 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 standcock was then opened, and the jet from the first was 45 feet high.
3rd. The third standcock was opened, and the jet from the first 40 feet high.
4th. The fourth standcock being opened, the first gave a jet of 35 feet high.
5th. The fifth being opened, the first gave a jet of 30 feet high.
6th. All the six being opened, the first gave a jet of 27 feet in height.
2nd Experiment.—Six standcocks were then put into plugs, on a main 9 inches diameter in Tooley-Street, the extreme distance being 450 yards, with hose and jets as in the first experiment. The water was brought from the head at Battersea by 4250 yards of iron pipes of 20 inches diameter, 1000 yards of 15 inches diameter, 1400 yards of 9 inches diameter. The weather was nearly the same, but the place of experiment was more protected from the wind than in Union-street.
1st. With one standcock open, a jet 60 feet in height was produced, and 107 gallons per minute were delivered.
2nd. The second standcock was then opened, and the difference in the first jet was barely perceptible.
3rd. Other two standcocks being opened, the first jet was reduced to 45 feet in height, and the delivery to 92 gallons per minute.
4th. All the six standcocks being opened, the first jet was further reduced to 40 feet high, and the delivery to 76 gallons per minute.
3rd Experiment.—Two standcocks, with hose, &c., as in the first experiment, were then put into a service-pipe, 4 inches diameter and 200 yards long, in Tooley-street, the service-pipe was connected with 200 yards of main 5 inches diameter, branching from the main of 9 inches diameter. The weather was still the same as at first, but the wind did not appear to affect the jets, owing to the buildings all round being so much higher than the jet.
1st. The standcock nearest the larger main was opened, and a jet of 40 feet high was produced, delivering 82 gallons per minute.
2nd. Both standcocks being opened, the first gave a jet of 31 feet, and delivered 68 gallons per minute.
3rd. The standcock farthest from the large main only being opened, gave a jet of 34 feet, and delivered 74 gallons per minute.
4th. Both standcocks being opened, the farthest one gave a jet of 23 feet, and delivered 58 gallons per minute.
When both these plugs were allowed to flow freely without hose, the water from that nearest the large main, rose about 18 inches, and the farther one about 1 inch above the plug-box.
These and other experiments prove the necessity of placing the plugs on the mains, and not on the service pipes, where there are mains in the street.
The different modes of obtaining water from the mains or pipes are shown in the accompanying drawings.
section of the common plug, with a canvas dam or cistern over it, as used in London. The cistern is made of No. 1 canvas, 15 inches deep, extended at top and bottom by 5/8-inch round iron frames, a double stay is hinged on the top frame at each end. When the cistern is used the top frame is lifted up, and the stays put into the notches, in two pieces of hoop iron, fixed to the bottom frame.
There is a circular opening 9 inches diameter in the canvas bottom, two circular rings of wash-leather, about 2 inches broad, are attached to the edges of the opening in the canvas, so as to contract it to 4 inches or 5 inches diameter; the plug being opened, the cistern is placed over it; the wash-leather is pressed down to the surface of the road by the water, and a tolerably water-tight cistern, with about 12 inches or 14 inches of water in it, is immediately obtained.
It will be observed, that the short piece of pipe between the main and this firecock is not curved to the current of the water, but merely opened a little; this is done with a view of increasing the supply by steam power, and as the steam engines are, in most cases, situated in a different direction from the tanks or reservoirs, therefore the curve that would have assisted the current in one direction would have retarded it in the other. It has been objected to these firecocks, that the opening does not run through the centre of the key, therefore only one side of the key covers the opening in the barrel, while in the common firecock both sides are covered.
as the pressure of the water forces the key into the barrel; this also renders the cock somewhat difficult to be opened and shut, if the pressure be great; but as a lever of any length may be used, and the key, from its perpendicular position, may be loosened by a blow, this objection is in a great measure obviated.
The plug and firecock have both certain advantages and disadvantages, which are now described.
The plug, with a canvas cistern, is the easiest mode of obtaining water; the plugbox being only the size of a paving-stone, is no annoyance in the street, and the water has only one angle to turn before it is delivered.
On the other hand, where the supply of water is limited, the plugs give but little command of it; there is, however, comparatively very small loss at a large fire in London from this cause, as it is very seldom that all the fire-engines can be supplied direct from the plugs, and those that arrive late must pick up the waste water as they best can, by using another description of canvas dam, or opening the street; but in enclosed premises, especially where the water is kept for the purpose of extinguishing fires, firecocks are much to be preferred. It is very difficult to insert the standcock into a plug if there is a considerable force of water, and if the paving has moved, it cannot be done without raising the plugbox; but this is, however, the easiest mode of using firecocks, and where there is a considerable pressure of water, if the watchmen or the police are supplied with a hose-reel and branch-pipe, they can, in enclosed premises, direct a jet on the fire while the engines are being prepared, and if they cannot reach the fire, they will have water ready for the engine when it arrives.
Inclosed premises are particularly mentioned, because the principal duty of the watchmen, in these cases, is to guard against fire, and their other duties being comparatively few, the men are not often changed, and they can be instructed thoroughly in the matter. With the general police of the metropolis it is quite different, their duties are so numerous and varied, that to add that of firemen to them would only be to confuse them.
The advantage which the double firecocks have over the single ones, is merely the increased water-way, as a firecock 3-1/2 inches diameter could not be so easily opened or shut, as two cocks of 2-1/2 inches diameter.
One of the greatest objections to firecocks, is the very large openings required in the streets, the first cost and the repair of which are both considerable, besides their liability to accident. To take them to the footpath, increases the expenses and diminishes the supply of water, as it is generally done with a small pipe, and the number of angles is increased. In some instances, where firecocks have been put down on one side of the street, no less than four right angles have been made in the course of the water; and if the fire happens to be on the opposite side of the street from the firecock, the thoroughfare must be stopped. The expense also is no slight consideration, for if laid along with the water-pipes, each firecock, if properly laid, and the pit built round with cement, will cost eight or ten times as much as a plug.
London is, upon the whole (except in the warehouse districts), fairly supplied with water for the average description of fires, that is, where not more than five or six engines are required. When, however, it is necessary to work ten or twelve engines, there is very often a deficiency. In many of the warehouse districts the supply is very limited indeed, although it is there that the largest fires take place.
The water companies are generally willing to give any quantity of water, but they object to lay down large mains without any prospect of remuneration. The warehouse keepers decline to be at the expense of laying the pipes, and there the matter seems to rest. In most other places of importance, the water is under the management of the civic authorities, and they, of course, endeavour to obtain a good supply of water at fires in warehouse as well as in other districts.
In supplying fire-engines with water from firecocks, one or more lengths of hose are screwed on the firecock; the extreme end being put into the engine, the firecock is then opened and the water rushes in. When the water-pipes are large and the pressure considerable, two or even three engines may be supplied from the same firecock.
If the firecocks are all at too great a distance from the place on fire, to be reached by the supply of hose brought with the engine, the next resource is, to open the nearest firecock above the level of the place where the water is required. By covering the eyes of drains, and stopping up any cross-water channels, the water may in this manner be conveyed along the street, from a very considerable distance. From the nature of the ground it does not always happen that the water will run directly from the nearest firecock, to the spot where it is required; acclivities, buildings, and many other causes, may prevent this; but in some of these cases a few lengths of the hose, attached to the firecock, may convey the water to a channel which will conduct it to the required point. Upon the arrival of the water, it ought to be dammed up, and the engine will lift it by suction out of the pool so formed.
If, however, from the nature of the ground, from the want of hose, or from other causes, it is found impracticable to convey the water by either of the above methods, the next best is, to conduct the water in hose as far as can be accomplished, and carry it the remainder of the distance in carts, buckets, or whatever else may be most convenient.
When carried in buckets it is of advantage to form a line of men from the water to the engine, each man covering five or six feet of ground. The buckets are then handed from one man to another, till they reach the two or three men who are stationed round the suction-tub or fire-engine to receive them. The buckets when emptied are returned by a different line of men (women or boys) stationed in the same manner as the former. If a sufficient number of hands cannot be had to return the buckets in this manner, any convenient number may be employed to carry them to the firecock, that they may be again filled. When a fire occurs where the water-pipes are unprovided with firecocks or plugs, the ground should be immediately opened, and the water-pipe cut. If it be of cast-iron, a large hammer may effect the purpose: on the water-pipe being broken, the suctionpipe of the engine is placed in the opening so made. If the pipe be of lead, the opening in the street should be made of sufficient length to admit of one end of it, when cut, being turned into the engine. If the supply of water by this means be so great as to occasion waste, it may be regulated by the nearest stopcock on the water-pipe, by driving a wooden plug into the end of a cast-iron pipe, or compressing the end of a leaden one.
The next plan I shall notice of supplying fire-engines is from drains, gutters, &c.
In particular situations and wet weather considerable supplies of water from these and similar sources may be obtained. In the gutters all that is required is to dam them up; and, if there be no materials at hand for this purpose, the causeway must be dug up, till there is a sufficient depth of water for the suction-pipe of the engine.
When the water is to be drawn from drains or common sewers, great care should be taken not to damage them farther than is absolutely necessary.
If enough of cover be taken off to allow one man to enter easily, it will be quite sufficient for all necessary purposes. When the man inside the drain or common sewer has collected a proper supply of water by damming up the channel, the suction-pipe should be handed down to him, and the engine set to work.
Although it be true that foul water quenches fire, I will here observe, that the water from a common sewer should never be used, except when it is impossible to procure it from a purer source. For the purpose of procuring water to extinguish a fire, I had at one time occasion to open a common sewer, in which, with the usual impurities, the waste from a gas manufactory was intermixed, and the stench in the premises where the fire had been extinguished by this water, was for some time after very disagreeable.
If the water be obtained from a pond or river at a little distance, one engine may be stationed close to it, and that engine made to pump the water into another at work. If the water be conveyed in carts, an engine may be kept at the pond or river for the purpose of filling them. Of course this can only be done where there is a proper supply of engines.
In working from an open water, such as a gutter, drain, river, or pond, it is proper, in order to prevent sand or gravel being drawn into the engine, to sink an iron or wooden bucket, into which the suction-pipe of the engine should be placed. If nothing better can be had, a good wicker basket will be found useful.
It is of great advantage to have a number of carts, with butts upon them full of water, as it ensures a small supply to the engines the moment they arrive at the fire. This plan, however, entails a very considerable expense, as carters must be paid for taking them out on every alarm, besides giving prizes to the owners of the first and second horses, to ensure their coming in time.
FOOTNOTES: [F] At a fire which took place in one of the best streets in Edinburgh, and which began in the roof, the persons who rushed into the house on the first alarm being given, threw the greater part of the contents of the drawing-room and library, with several basketsful of china and glass, out of the windows; the fire injured nothing below the uppermost story.
[G] The engines and their crews are distinguished by these colours.
[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-cock (as the case may be): by this method all the water is pressed out.
[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.
[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.
[K] Now Shand, Mason, and Co.
[L] This description applies to the most recently constructed fire-engines belonging to the Metropolitan Fire Brigade.
[M] "Stuffing," a technical term need by leather-dressers or curriers.
[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.
[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.
[P] See engraving of portable cistern, page 156.
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