BUILDINGS. The problem of constructing warehouses, dwelling-houses, etc., that shall be proof against all risk of conflagration, has not yet been solved. The liability to conflagration may be greatly diminished by the construction of a building, but cannot be entirely averted ; and therefore, in all " fire-proof " buildings containing furniture or other combustible materials of any kind, the ordinary precautions against fire should be strictly observed. It is well to state this at the outset, as, unless it be understood, a so-called fire-proof building may be more dangerous than an ordinary one, especially in warehouses, etc., intrusted to the care of watchmen and others, rely ing upon the supposed immunity the name expresses, are liable to neglect many pre cautions they would not fail to observe in a building believed to be dangerous. The most destructive fire that has occurred in London since 1666 was that at Cotton's wharf, in 1861, the warehouses of which were what is called " fire-proof." The great fury of this conflagration depended on the nature of the goods that were stored. It is scarcely possible to believe that such combustibles as tallow, turpentine, etc., could have been stored in the vicinity of saltpeter, unless there had existed some faith in their practical isolation from each other by the fire-proof divisions of the building, as it is so well understood that saltpeter, though incombustible of itself, intensifies to an immense extent the combustibility of all combustibles, by supplying them with undiluted oxygen when heated in contact or within a moderate distance of them.
The nearest approximation to fire-proof construction may be obtained as follows: The walls should be of stone or brick, and any ties, lintels, etc., required in the construc tion should be of iron. The staircases should be of iron or stone, and the floors or land ings of tiles, concrete, or stone. Wherever wood is inevitably used, it should be pre pared with silicate of soda (see FIRE-PROOFING). Instead of wooden joists to support the floors of each story, arched stone or brick work should be used, and this should be put together with sufficient care to be independent of the mortar. The roof should be constructed in like manner, wooden rafters being entirely excluded. The doors should be of iron, and the security would be much increased if the doors between any two apartments containing combustible materials were double, with a space between them equal to the thickness of the walls. Of course, it is not practicable to carry out all these
precautions in a dwelling-house, but the danger from fire may be considerably dimin ished by attending to some of them. Wooden staircases are especially dangerous. The most important conditions for a warehouse are, that each apartment shall be separated from the next by stout walls of non-conducting materials, and more especially, that each shall be as nearly as possible air-tight; and whenever, from the nature of the goods, ventilation is required, it should be obtained by periodically opening the doors and windows. If this latter condition is fulfilled, any fire would extinguish itself, unless there be along with the combustible goods some oxygen-giving substance, such as salt peter, chlorate of potass, or other nitrates or chlorates.
At first sight, it may appear that a warehouse built entirely of iron would be effect ually fire-proof, but this is far from being the case. In the first place, iron conducts heat more readily than any other material used in building; secondly, cast-iron is liable to crack and split when suddenly heated or cooled. Iron supports may, under some circumstances, be even more objectionable than wood, for if the water from a fire-engine were to play upon a heated cast-iron girder, it would probably give way immediately, while a stout wooden beam might be extinguished before being burned through. When buildings supported by iron girders are burning, they are far more dangerous to firemen than those with wood, as the experienced fireman can form a pretty accurate judgment of the time that burning wooden beams will stand, and may move about in their vicin ity to direct the stream of water to where it is most needed, but iron girders split and fall without visible notice. It is on this account that floors of arched masonry are recom mended above. In great fires, the heat is sufficient to fuse iron.
Without going to the expense of making warehouses and manufactories absolutely fire-proof, certain precautions not of a costly nature might be usefully adopted, for the purpose of merely checking the progress of conflagration until the arrival of fire-engines.' Among these simple measures, may be included iron doors hinged on stone between different departments; a sufficient deafening not easily destructibh between the ceiling of one story and the floor of that above ; and stone stairs. For rendering timber diffi cult of combustion, see FrvETItooFirig. See also ,SAFF:S,,FIRE-PRO,OF,