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in weight will be exerted to pull and latch the door closed. The cord sheaves must be securely fastened to the wall with expansion bolts, and must be provided with bronze bearings, and so constructed that the cord cannot jump the grooves. The latch must be provided with a suitable coiled spring to hold it in place and to insure fastening.
Automatic swinging doors require a different arrangement of the link and weights closing the doors. Weights to be properly boxed and placed between doors. Cords to pass through holes drilled in wall frame and to be so arranged in sheaves that the f-.sing of the link will release sufficient weight to pull and latch the door closed. Fusible links to be placed near the ceiling and arranged so that the fusing of the link on either side of the wall will operate both doors; several links may be placed on either side if desired. The cords closing doors should be sufficiently weighted to keep them taut when the doors are opened and closed. When these doors are in pairs they must be so arranged that the right-hand doors will fold over the left-hand doors. This requires an automatic stop or trigger at the top of the doors, which will hold the right-hand sufficiently open to allow the left-hand door to close first. The closing of the left-hand door releases the trigger and allows the remaining door to close. The left-hand door to be provided with spring bolts or latches at both top and bottom, these to be operated from either side of the door by proper handles at the centre.
STANDARD SHEET IRON DOORS (National Board of Fire Underwriters).—These doors are lighter than the vault doors and differ from them in the following particulars. No. 12 guage sheet iron or steel is used instead of 3-16-inch plate, panel frames and bars are made of 2 x 2 x J4-inch angle iron instead of 2 x 2 x J^-inch.
Standard sheet iron doors may be used in less closely built up districts and in localities where exposure is not liable to hsevere. They are not recommended.
STANDARD IRON SHUTTERS (National Board of Fii Underwriters).—Must be made of sheet iron or steel, No. 14 gauge and lap the wall at least V/2 inches all around; if not practical to lap at the bottom must fit the sill closely. Frames to be of V/2 x ;4-inch angle iron, with not less than two cross bars of the same material, and to enter wall opening when shutter is closed. Shutters over six feet in height to have cross bars not exceeding two feet apart. To have not less than two lever bars, extending at least one-third of the distance across the opposite shutter, when double shutters are used, of V/2 x J^-inch iron, and where over six feet in height lever bars not to exceed two feet apart; these bars to work together by J^-inch connecting rod and fastened into substantial lugs, riveted on each shutter or to proper fastenings in the brick wall if the shutters are single. Hinges to be of 2}4-inch iron, extending at least three-fourths of the way across the shutter, and not to exceed two feet apart when the shutter is over six feet in height. Pin blocks or shutter eyes of j4-inch round iron, to be securely set in brick walls, preferably while building. On finished buildings pin blocks or eyes should be firmly set in holes drilled in brick and fastened with iron wedges and cement. Rivets to be of iron at least 5-16 inch in diameter, and placed not exceeding six inches apart. Hooks or gravity catches in wall to be provided to hold shutter in position when open. At least one shutter in three on each floor above the first to be constructed so that it can be operated from the inside and outside, the handles on the outside to be so constructed that they can be operated by hand or pike pole. Shutters to be thoroughly painted with two coats of iron oxide and boiled oil or equivalent.
STEEL ROLL FIRE DOOR AND SHUTTER (National Board of Fire Underwriters).—Should not be used where standard fire doors and shutters can be employed; otherwise for front or rear openings, exposed across narrow streets or alleys, they are recommended if of approved construction.
NOTES.—All materials used to be carefully and thoroughly straightened before the door is put together. Scrap or short pieces not to be used where such material should be avoided. Rivets to be drawn tight. Doors to be made, finished and hung n a thoroughly workmanlike manner. Strips to be screwed to loor and heads of screws must be countersunk.
Arrangement and Setting Up.—The thickness of the wall should be accurately measured, so that the bars or bolts fastening wall frame together can be cut to the exact length. If the door is not installed when the wall is erected, or is not placed in an old opening, the opening should be cut larger than the frame and the jambs built up to the proper size, using cement mortar and thoroughly pointing up around frames. Frames to be set perfectly level and plumb and doors hung so as to fit the wall frame closely all around. All doors to swing or slide freely and without binding, care being taken to see that the latches or lever bars fasten properly.
Use tin plate 14 x 20 inches, "IC" charcoal, 108 pounds to the box.
When necessary a light frame work of slats should be built outside of sliding doors to prevent piling of stock, etc., against them.
Bright tin doors resist fire better than if painted.
Do not paint the doors unless it is necessary, and do not until they have first been given a coat of asphaltum. A light-colored paint does not absorb heat so readily as dark-colored paint.
It is well to paint all iron parts of doors with iron oxide mixed with boiled oil.
Fire doors and shutters should be ready for instant use at times, therefore it is necessary to keep the surroundings clear of everything that would be likely to obstruct or interfere with their free operation.
Fire doors and shutters should be kept closed and fastened at nights and on Sundays and holidays, and whenever the openings are not in use.
Never tack any tin on a tin-clad door or shutter.
When tin becomes worn substitute new sheets in the same manner as when covering a new door.
Sheet iron, galvanized iron and other thin sheet metals, excepting proper sheet tin, are of practically no value as coverings for fire doors, as they do not adequately withstand heat, rust away, cannot be properly put on the woodwork, and buckle and bend with comparatively little heat.
Metal-clad doors, with the sheet metal nailed on in such a manner as to expose the nail heads, are of but little value as fire doors, as the heat will cause the nail to char the surrounding wood and the spring of the sheet metal will then force the nail out and drop the metal from the wood.
Sheet metal put on woodwork otherwise than lock jointed will not prove of much value, as the heat will soon reach the wood between the sheets.
Soldered joints must not be used, as the solder will melt and the joints come apart.
The fire resisting value of a wood door encased in tin depends upon the exclusion of oxygen from the wood, thereby retarding or preventing combustion. To obtain this result the tin must be so applied that during exposure to fire the tin will not leave the door nor will any joints or seams buckle open by expansion so as to expose the wood.
No exposed wood should be anywhere in the fire door, shutter, door frame or door sill.
Heating appliances are of such diverse characters, constructions and uses, that no general ruling can be given as to their construction, location or arrangement; that they should not be hazardously close to inflammable material is, of course, a necessary requirement, hence a free ventilating air space should be provided about them, and they should not be shut up in close, contracted locations, and all woodwork exposed to the heat should be adequately protected.
All woodwork directly exposed to any boiler, steam dome of boiler, breeching or flue should be covered with sheet asbestos overlaid with tin (standard clad), both closely following all lines and angles of the woodwork. A metal shield with air spaces on both sides affords some protection, but is not generally efficient for the purpose of protecting the wood from the action of the heat.
It is best from a point of economy, as well as a safe-guard from fire, to set all boilers and other heat-producing appliances allowing of same, in brickwork and covering them with some non-heat-conveying material. The loss of heat means the loss of just so much fuel to produce it, hence all heat wasted is fuel wasted, and in the operation of manufacturing plants this is a very decided item for the practicing of economy; the covering of steam pipes with the various coverings for retaining heat is a point in which one economy of operation in a manufacturing plant is exhibited, therefore the covering of all heat-producing appliances to reduce heat radiation where the heat is not needed acts as much in the interest of economy as in the reduction of the fire hazard, but it is not well to cover a pipe to a floor or partition, let it run through these bare, and then cover it on the other side of the floor or partition, for then an excess of heat is retained at the worst possible point, the covering of heat-conveying pipes where they pass through wood or any