FIRE COLLEGE EXTENSION COURSE
Copyright, 1920, by FIRE AND WATER ENGINEERING, INC.
(Continued from page 787)
BUILDING CONSTRUCTION: ITS RELATION TO FIRE FIGHTING, INSPECTION, AND FIRE PROTECTION
Before entering into the subject assigned to me, there is one point which must be understood in this or in any other lecture given by any of the chief officers or myself, and that is: The principal purpose of the college is to train men to think and to reason. It is not so much the few facts or illustrations which may be conveyed to you during the course that count. In the course of a lecture it is necessary to use a few specific points to illustrate some particular lesson or thought, but if you simply absorb these few points, memorize them, and let it go at that, your effort and time and the effort of the instructors are wasted.
Carry out the reasoning completely; apply it on all occasions; observe how the conditions are found in actual work; supplement the knowledge gained at this college with continual reading on the subjects discussed. Go to the library and get a few books, read them over so each particular point may be thoroughly understood. Get a book on architecture or on carpentry. Look at the illustrations first. It will interest you to know just what is behind the framework of a window casing, or between a floor surface and the ceiling. Find out how the nails are placed. Then your work of cutting up a floor or wall at a fire will be play. The hardest kind of work is caused by men either misdirecting their efforts or working without a thorough knowledge of what they are doing or why they are doing it.
Chief Kenlon in his talk to the officers of the fire department attending this term of the fire college, stated that it is just as essential for officers and firemen to know and understand the framework or skeleton of structures in which and upon which their efforts and operations are applied in the course of their work, as it is for a physician or surgeon to understand the human body, its skeleton, muscles, nerves, and all their functions.
The proof of this statement is plain to any officer who thinks and who seeks to excel in any fire department. In the following topic on building construction, an effort will be made to show why it is necessary that the framework of buildings be thoroughly understood, and why a general knowledge of the trades of masonry, carpentry, joinery, structural iron-working, as applied to buildings, add to intelligent operations at fires.
Man’s problem of providing shelter for himself and his kind began with the race. It was a natural tendency to use the material nearest at hand and that most easy to apply. In this country with abundant forests and woods, and an inherent tendency among our people for continual change, it was also natural that frame construction, buildings entirely of wood, should have been the class of structure most used by the people of America.
From the log cabin we progressed to the frame farm house, to the colonial mansion, and even to frame tenements in our cities. Fire prevention experts, in making comparisons between the annual fire losses and the number of fires in Continental Europe and in America, seem to ignore the primary consideration of the immense problem with which our fire fighters must contend through the heritage of our forefathers, and of American tendencies and conditions. Our buildings and our homes contain, perhaps, articles and values of more than 50 per cent in excess of those found in European homes. What is a necessity to an American would be a luxury to people in Europe, and we store these valuables in houses that burn readily.
There are two general types of frame-constructed buildings; the braced frame and the balloon frame. It has been my experience that members of fire departments are in the habit of reading and absorbing information without really understanding the meaning of terms, and if any subject is to be understood, it is necessary that every term be looked up and the student understand its meaning.
The definition of braced frame is: Each piece of the structure is carefully fitted and fastened to every other piece that it comes in contact with and the whole skeleton thereby made stiff and secure before any covering material is applied. See Fig. 7.
Balloon frame means: The timbers are simply nailed together and the entire structure depends entirely upon the outer sheathing or covering for strength and security. See Fig 8.
The first type was used in the olden times, when nails, bolts and iron straps were made by hand and required more time and labor than cutting mortise and tenon joints. (Fig. 9.)
With the advent of machine-cut nails, bolts and straps came the balloon frame, which, though somewhat flimsy in itself, is, after the outer sheathing is on, much stronger and stiffer than the regular or braced frame, and costs about one-half the money to erect. That is, it is stronger in so far as maintenance and ordinary structural strength is concerned, but if attacked by fire, owing to the small dimensions of its timbers, boards, etc., with many concealed spaces and openings through which fire may travel, and the fact that all parts depend on all adjacent parts for general stability, it requires eternal vigilance and quick work for the firemen to save the foundation once fire gains headway.
In erecting this type, after the foundation is laid (foundation may be stone, brick or concrete) a sill is laid in a bed of lime mortar on the foundation wall and well bedded by means of repeated blows with a heavy hammer, or the sill may be anchored to the foundation by means of anchor bolts. Then the first floor tier beam are laid. If the span is too great, a girder carried on posts will be carried through the center of the house. Floor beams are nailed to the sill, and crossbridging (Fig. 10) is put in to strengthen the floor and prevent side warping. Corner posts are then set; the studs are next placed, usually 16 inches apart. A point well worth remembering is that 16 inches is a measurement used in many instances in building construction. If it is necessary to cut open a wall or to strip off the lath and plaster, when you locate one stud you know the next stud is about 16 inches away. Studs are “notched” at the height of the second story, and “ledger boards,” on which the second story floor beams will be supported, are nailed in the notches.
Framing for doors and windows is then placed; usually the studs are doubled on each side of the opening and spiked together; the head and sill of the opening are also double studs, and if the opening is over three feet in width, the top should be trussed. While the tiers or floors are being carried up, the sheathing of 7/8-inch boards is applied. Sheathing is always laid diagonally, for it is upon the bracing effect of diagonally placed sheathing that the building depends for strength. Then the floor boards are laid and the structure is ready for the roof timbers. The rafters are set and nailed. The shingle lath to which the shingles will be nailed are put on, and the skeleton is up and covered with its sheating.
The next step is the inside and outside finish. Carpenters lath the partitions, cross-furr and lath the ceilings, set the frames of windows and doors, put on the clapboards or siding, shingle the roof, and the house is now ready for the plasterers and painters. The spaces between the sheathing on the outside and the lath and plaster on the inside, the width of the studding from the builder’s standpoint, is considered a necessary air space to insulate the interior of the house from the outside temperature, but it is this space that provides the great hazard in case of fire. A fire starting in any part of the building, and particularly in the cellar or lowest story, and then burning into the walls, travels up and behind the walls and spreads throughout the building. The average layman in whose home fire may occur remarks with wonderment and disgust: “Why, the fire was down in the cellar, but the firemen went into my bedroom on the top floor and pulled down the wall looking for it.”
(To be Continued)
The New York Fire College Course, which has been running serially through the volumes of FIRE AND WATER ENGINEERING, has been issued in book form of convenient size, 9×12 inches, well printed in plain, readable type with full illustrations. The book contains all of the lectures of the complete course and has been compiled in answer to a very strong demand from the members of the fire departments who have desired to have the course in convenient form for reference and preservation, without mutilating the copies of FIRE AND WATER ENGINEERING which they have on file. The book will be presented only upon request gratis to all subscribers of FIRE AND WATER ENGINEERING whose subscription accounts are paid up on May 1. The free offer will be withdrawn after that date. If your subscription has already been paid, write immediately for the book, otherwise it will be understood that a copy is not desired. It is a work every fireman should have in his hands for reference and study.