There obviously must be a limit to the endurance of safes; therefore a guarantee is as obviously an absurdity, and ought not to be blindly believed in.
CHAPTER VI.
STRONG-ROOMS.
IN the planning and construction of a strong-room it must be remembered that the object sought is to obtain a place secure against both the attack of thieves and the ravages of fire.
There are many cases, however, where the latter is the chief object; and as the attainment of this is more difficult than the former, it will necessarily come before us more prominently. In many respects this subject is the most important in this treatise, and it is one concerning which there is a great amount of ignorance. Bearing in mind the rapid spread of banking and other businesses requiring the security a good strong-room affords, it will be my object to show the faults of many constructions now relied upon, and to suggest the simple ways by which they may be avoided.
Building a single strong-room is a very different matter from erecting a fireproof building; the latter is a larger and more difficult question, which will be noticed by itself; but the room that is to be made secure may be and generally is part of a building with no pretensions to special safety against fire or thieves.
Now, the first thing to consider is the position best adapted in any bank, mansion, or warehouse for placing the more valuable part of its contents. There may be certain parts which seem most convenient for access or other reasons, but such considerations ought never to be taken first, especially as the best place happens to be often rather inconvenient. The basement is undoubtedly the right position; any part of the basement will do, but a room on the ground or first floor has at once a source of weakness in itself, for it has to depend for support on what is not a strong-room. Let some spot be chosen in the basement where, if possible, the room will have none of its walls adjoining any other buildings. Should it be next to a street or thoroughfare, it will not matter; but it should not adjoin a court or area, where burglars might have an opportunity of working unobserved. It would undoubtedly be an excellent precaution to build all the walls quite distinct from the main walls of the larger structure, but this is not absolutely necessary, and the extra expense is a drawback to it, though I would give a caution against false economy in such a matter as this.
Any position likely to be damp should be avoided; but if this is not possible every precaution should be taken to remedy the evil, for the trouble caused by damp when once it has got into a closed room of this kind is endless. A few air-bricks connecting the inside by a hollow flue formed in the wall, with its outlet as far as possible from the inlet, should be sufficient to ventilate any strong-vault. But if other ventilation is necessary in the room, have a jet of gas always alight; and over the gas place a bell-shaped covering communicating with the outer air, or with a chimney flue in preference, by a two-inch iron pipe.
In excavating for the foundations, if the subsoil and the situation are not well known, it is important to see that there is no drain or pipe of any sort under the surface, and that the ground is stiff enough for the heavy weight that will be on it. One of the most important parts of a strong-room is the floor, although there is a popular delusion that because it is the floor it is quite secure without any protection. A circumstance showing the necessity of being careful to make the floor strong occurred in the early part of the year 1865, at Hong Kong. The Central Bank of Western India, situated there, had a strong-room for its securities, but unfortunately the defence of the floor seems to have been forgotten. Accordingly some thieves commenced to make a tunnel from a neighbouring house, and after considerable labour obtained entrance through the floor and carried off plunder to the amount of fifty thousand pounds. The affair was managed during Saturday and Sunday by means of this tunnel dug between a drain and the floor of the treasury, a horizontal distance of sixty feet.
A New York bank was also entered in a similar manner, through an excavation which must have taken two or three weeks to make. Although such approaches may occupy some time, they can be carried on unnoticed until the removal of a stone in the floor is at last only the work of a few minutes. For the floor to be secure, it should certainly be formed of half-inch boiler-plates rebated and fastened together, laid upon a good thickness of brick and cement. Stone has been constantly recommended and used for flooring, but it is not advisable; there ought not to be any stone in a strong-room except for the sill and lintel of the doorway, where it is almost necessary.
The walls must be at least fourteen inches thick, brick and cement, and there ought to be the boiler-plate lining inside wall and roof to correspond with the floor.