Fire prevention and fire extinction

by James Braidwood

From 1838 to 1843, 776,762l. were lost in Liverpool by fire, almost entirely in the warehouse risks. The consequence was, that the mercantile rates of insurance gradually rose from about 8s. per cent. to 30s., 40s., and, it is said, in some cases, to 45s. per cent. Such premiums could not be paid on wholesale transactions, therefore the Liverpool people themselves obtained an Act of Parliament, 6 and 7 Vic., cap. 109, by which the size and height of warehouses were restricted, party walls were made imperative, and warehouses were not allowed to be erected within thirty-six feet of any other warehouse, unless the whole of the doors and window-shutters were made of wrought iron, with many similar restrictions. This Act applied to warehouses already built as well as to those to be built, and any tenant was at liberty, after notice to his landlord, to alter his warehouse according to the Act, and to stop his rent till the expense was paid. Another Act, 6 and 7 Vic., cap. 75, was also obtained, for bringing water into Liverpool for the purpose of extinguishing fires and watering the streets only. It is supposed that the works directed, or permitted, by these two Acts, cost the people of Liverpool from 200,000l. to 300,000l. Shortly after these alterations had been made, the mercantile premiums again fell to about 8s. per cent.

There is another very common cause of fire, which seems to come under the head of construction—viz., covering up a fireplace when not in use with wood or paper and canvas, &c. The soot falls into the fireplace, either from the flue itself, or from an adjoining one which communicates with it. A neighbouring chimney takes fire; a spark falls down the blocked-up flue, sets fire to the soot in the fireplace, which smoulders till the covering is burned through, and thus sets fire to the premises.

In theatres, that part of the house which includes the stage and scenery should be carefully divided from that where the spectators assemble by a solid wall carried up to, and through the roof. The opening in this wall for the stage should be arched over, and the other communications secured with iron doors, which would be kept shut while the audience was in the house. By this plan, there would be abundance of time for the spectators to retire, before fire could reach that part of the theatre which they occupy.

The danger from furnaces or close fires, whether for heating, cooking, or manufacturing purposes, is very great, and no flue should be permitted to be so used, unless it is prepared for the purpose. The reason is, that in a close fire the whole of the draught must pass through the fire. It thus becomes so heated that, unless the flue is properly built, it is dangerous throughout its whole course. In one instance of a heating furnace, the heat in the flue was found to be 300°, at a distance of from forty to fifty feet from the fire. In open fireplaces, the quantity of cold air carried up with the draught keeps the flue at a moderate heat, from the fire upwards, and, unless the flue is allowed to become foul, and take fire, this is the safest possible mode of heating.

Heating by hot air, steam, and hot water are objectionable. First, because there must be a furnace and furnace flue, and the flue used is generally that built for an open fire only; and second, the pipes are carried in every direction, to be as much out of sight as possible. By this means they are constantly liable to produce spontaneous ignition, for there appears to be some chemical action between heated iron and timber, by which fire is generated at a much lower temperature than is necessary to ignite timber under ordinary circumstances. No satisfactory explanation of this fact has yet been given, but there is abundant proof that such is the case. In heating by hot-water pipes, those hermetically sealed are by far the most dangerous, as the strength of the pipes to resist the pressure is the only limit of the heat to which the water, and of course the pipes, may be raised. In some cases a plug of metal which fuses at 400° is put into the pipes, but the heat to which the plug is exposed will depend very much on where it is placed, as, however great may be the heat of the exit pipe, the return pipe is comparatively cool. But even where the pipes are left open, the heat of the water at the furnace is not necessarily 212°. It is almost needless to say that 212° is the heat of boiling water under the pressure of one atmosphere only; but if the pipes are carried sixty or seventy feet high, the water in the furnace must be under the pressure of nearer three atmospheres than one, and therefore the heat will be proportionately increased. Fires from pipes for heating by hot water have been known to take place within twenty-four hours after first heating, and some after ten years of apparent safety.

The New Metropolitan Building Act prescribes rules for the placing steam, hot-air, and hot-water pipes at a certain distance from timber; but as it must be extremely difficult for the District Surveyors to watch such minute proceedings, it becomes every one who is anxious for safety to see that the District Surveyors have due notice of any operation of this kind.

Another cause of fire which may come under this head is the use of pipes for conveying away the products of combustion. Every one is acquainted with the danger of stove pipes, but all are not perhaps aware that pipes for conveying away the heat and effluvia from gas-burners are also very dangerous when placed near timber. It is not an uncommon practice to convey such pipes between the ceiling and the flooring of the floor above. This is highly dangerous. Gas-burners are also dangerous when placed near a ceiling. A remarkable instance of this took place lately, where a gas-burner set fire to a ceiling 28-1/2 inches from it.

Another evil of furnaces is, that the original fireplace is sometimes not large enough to contain the apparatus, and the party wall is cut into. Perhaps it may be necessary to notice at this point the use of gas, as it is becoming so very general. Gas, if carefully laid on, and properly used, is safer than any other light, so far as actually setting fire to anything goes, but the greater heat given out so dries up any combustibles within its reach, that it prepares them for burning, and when a fire does take place, the destruction is much more rapid than in a building lighted by other means. Gas-stoves, also, from the great heat given out, sometimes cause serious accidents; in one instance, a gas-stove set fire to a beam through a two-and-half inch York landing, well bedded in mortar, although the lights were five or six inches above the stone. This is mentioned to show that gas-stoves require quite as much care as common fires.

Spontaneous ignition is believed to be a very fruitful cause of fires; but, unless the fire is discovered almost at the commencement, it is difficult to ascertain positively that this has been the cause. Spontaneous ignition is generally accelerated by natural or artificial heat. For instance, where substances liable to spontaneous ignition are exposed to the heat of the sun, to furnace flues, heated pipes, or are placed over apartments lighted by gas, the process of ignition proceeds much more rapidly than when in a cooler atmosphere. Sawdust in contact with vegetable oil is very likely to take fire. Cotton, cotton waste, hemp, and most other vegetable substances are alike dangerous. In one case oil and sawdust took fire within sixteen hours; in others, the same materials have lain for years, until some external heat has been applied to them. The greater number of the serious fires which have taken place in railroad stations in and near London have commenced in the paint stores. In a very large fire in an oil warehouse, a quantity of oil was spilt the day before and wiped up, the wipings being thrown aside. This was believed to have been the cause of the fire, but direct proof could not be obtained. Dust-bins also very often cause serious accidents. In one instance, 30,000l. to 40,000l. were lost, apparently from hot ashes being thrown into a dust-bin.

These accidents may in a great measure be avoided by constant care and attention to cleanliness, and where paints and oils are necessary, by keeping them in some place outside the principal buildings. Dust-bins should, as much as possible, be placed in the open air, and where that cannot be done, they should be emptied once a day. No collection of rubbish or lumber of any sort should be allowed to be made in any building of value.