Standard Storehouse Construction.
These illustrations represent salient points in design for a mill Storehouse several stories in height, and include many features found useful in practice for convenience in operation, and also securing the greatest measure of resistance to fire.
This plan is not intended to take the place of the services of any mill engineer, but rather to assise in such work. This office holds itself in readiness to furnish to its members estimates of the strength of floors. It is important that the floor beams should be designed to sustain the greatest load ever to be placed on them, and the stories should be made low enough to prevent overloading, and also to prevent bales of material from being piled to great height, the preferable method being to place bales on end.
These floors, with beams of twenty feet span, laid eight feet on centres, will sustain a load of 180 pounds per square foot, which is as much as would be required for raw material or finished goods of a textile or paper mill. The heavy drugs and dye stuffs would be placed on the ground floor.
For convenience as well as to separate the different hazards of raw material and finished goods, the building may be divided into two sections by fire walls extending through the roof
A storehouse one story in height is recommended in preference to this design whenever there is sufficient quantity of level land at disposal for this purpose, as being cheaper, more convenient and, when separated into small divisions by fire walls, the safest method of storehouse construction. Similar designs for one-story storehouses will be sent on application to persons connected with establishments insured in this company.
On reference to the drawing it will be seen that the floors are continuous, without openings and of the standard slowburning construction—a type which has not yet been burned through by any fire starting under such a floor, unless there have been openings in the floor. To reduce water damage the floors are not level, but have a camber of two inches in the middle, made by iron plates inserted under the columns in the basement. It it should become desirable to use the building for any purpose requiring level floors, they can be reduced to a level by removing these plates. Inclined iron tubes, with a light swinging cap on the outside, laid in the wall at the level of the floors, act as scuppers for the purpose of removing any water.
The floor beams are preferably of Southern pine bolted together in jiairs, leaving about one inch space between the beams. At the columns the beams are joined by dogs, made of three-fourths inch round iron, driven in at the top, and they are anchored to the walls by cast-iron wall plates, to which they are secured by means of a rib which fits into a groove crossing the under side of the beam. It is important that there should be a small space at each side and at the end of the beam, in order to allow free ventilation for the purpose of preventing dry rot. The Goetz box anchor is a special form of wall plate which is especially adapted to such purposes.
The under floor is made of spruce plank, generally three inches thick, planed on the underside and grooved at the edges, and fitted with hard wood splines. These plank are two bays in length, breaking joints at least every three feet. Over the plank are placed two thicknesses of rosin-sized paper before the top floor of hard wood is laid. The floor is smoother if laid across the line of plank, and the traveling loads moved in or out of the storehouse are better distributed than when the top floor is laid parallel to the plank. The floor should not be secured to the walls, but a narrow strip laid around the edges of the floor and fastened to the wall covers any openings due to shrinkage.
The columns should be square Southern pine or oak, with “iion cap, pintle and base, preferably cast in one piece, and secured to the under side of the beam by six-inch lag screws. The caps should be large enough to give the beams ample bearing surface.
If brick piers are placed in the basement, it is preferable rather than to insert bond stones in the piers, to use a plate of boiler iron the size of the pier, and containing a number of inch holes punched on both sides over a board, in order to produce as large burrs as possible to securely bold the masonry.
It is generally preferable that the roof should slope towards the centre one-half inch to the foot, and the gutter should slope towards the drain pipes one-twentieth inch to the foot ; but if the roof slopes towards the walls, the detail of cornice, A, illustrates the arrangement of gutters.
Access to the various stories is obtained only by means of a tower outside the main building and extending above the roof, containing stairways, elevator and water pipes. At each story of the tower open galleries communicate to the rooms on that level. A doorway from the upper story of the tower affords a ready means of reaching the roof. It is often a matter of great convenience if the doorway at the first story of the tower is made large enough, and at the outside grade, so that a wagon can be backed directly to the elevator. It is unnecessary to provide the elevators with automatic hatches, as guard gates serve every purpose. For the elevators in such towers. either hydraulic system or electric motors frequently furnish a more convenient means of applying the power than steam.
* By C. J. H. Woodbury, vice-president Boston Manufacturers Mutual Insurance Company.
The system of tram rails hung from above, in connection with triplex blocks, as constructed by the Yale & Towne Manufacturing Company, is a great convenience in handling the contents of storehouses.
The walls extend above the roof and the parapet should be laid in cement, because the moisture readily absorbed by brick would otherwise pass downward and render walls in the top story damp. In some instances a course of brick dipped in coal tar is laid above the roof level. The illustration, A, shows a method of protecting a low parapet wall by plank which is tinned. This form of parapet also tends to reduce the amount of snow lodging on the roof.
The window openings are small and omitted on sides exposed to other fire risks ; but if there is any contingency that the building will ever be used for other purposes, it is advisable to lay the walls with arches and panels, in which openings can be made suitable for windows of larger size, necessary to furnish light for manufacturing purposes.
In addition to yard hydrants near the buildings there should be a six-inch stand-pipe in the tower with two two and onehalf inch hydrants and hose at each story, and at the top story of the tower the stand pipe branches to a Morse monitor nozzle on the roof, if there are any adjacent buildings which might be reached by streams from this position.
A set of plugs for the roof drain pipes will allow the roof to be covered with water in case the property is endangered by sparks from burning buildings.
Automatic fire alarms with thermostats form a valuable auxiliary to the fire apparatus in storehouses.
If the contents of the storehouse are of such a nature that automatic sprinklers are advisable, it is preferable to shut off the water during freezing weather, rather than to rely upon the devices known as dry pipe systems.