MILL-CONSTRUCTION OF TO DAY

MILL-CONSTRUCTION OF TO DAY

WOOD VERSUS STEEL BEAMS IN A FIRE.

COMPLETE DESTRUCTION OF A MACHINE SHOP AT CLEVELAND, WHERE LITTLE INFLAMMABLE MATERIAL WAS USED.

(CONCLUDED)

In a building of mill construction, in addition to the fire-walls, with standard fire-doors at each, there should be incombustible fire-curtains. These are made of metal lath, in the roof—say, of a machine shop, with cement plaster or galvanised corrugated iron. They must be substantially erected. They must fit tightly, and are best fastened directly to the side of one of the trusses and to angle-iron secured to the under side of the roof-plank. If doors are necessary to provide access to overhead scaffolds or for any other purpose, they must be fire doors and should be provided with sprinklers on the under side.

THE BUILDING MATERIAL.

should be either rcinforc e d concrete, or the structure s h o u 1 d be substantially built of hnrdburncd brick. If these columns are to be used inside, and for the protection of structural steel or wrought iron generally so that it shall not buckle or bend under the action of heat, which it will do much sooner than stone, beams or posts of wood, they must be protected by fireproofing—an essential in buildings of more than one story, so as to prevent a fire in a lower story from bringing down everything above it. One illustrati’ n that accompanies this article shows the results of a fire, where the stability of the single 8 x 10-in. wooden timber roof was not affected, although the 10-in. steel beams sagged and were twisted to a degree that required rebuilding. This wooden beam was used, because not enough steel had been ordered to complete the work promptly. In rebuilding, wooden beams were used throughout.

THE ROOF.

which has already been spoken of, but simply with respect to the form it should take in the case of certain buildings. For factories and buildings in general and especially those in which light is an essential requisite, the value of a perfect light is being appreciated more and more.1 he best style, of course, is one that combines both safety and light. This is obtainable by the employment of the saw-tooth roof, with wooden framing. Of such roofs two illustrations are presented. One shows the saw-tooth extension, with the application of the principles of reinforced concrete, showing also an ample window-area in the side walls, which not only provide all the light possible, but, also, assist ventilation. The other is an interior of the room under the same roof. The very excellent diffusion of light from the saw-tooth form or skylight will be noted, the steel channel, beams being provided only for the support of the shaftings, while the supporting columns are non-combustible. The roof-covering—an important item—is composed of asphalt and slag on 3-in. roof-plank (it should never be less than 3-in.), grooved for hard wood splines. The wooden sashes are fixed double glazed, with yellow pine beams 8 to 3 ft.In the cut the tension rods are about -o ft. apart, the beam-hangers bolted through girders and joint bolts for beams; wood columns; i-in. maple top floor, I-in. rough; intermediate 4-in. plank grooved for hardwood splines; floor-beams about 8 ft. on centre; concrete basement floor; wood columns; cast iron post cap cast iron cap. Observe following details

ROOF COVERING.

Roof covering, pitch of valleys—the pitch is obtained by nailing pieces of varying height; trusses 8 to 10 ft. on centres; steel truss; metal sash, double glazed; structural and steel columns. The steel columns will, of course, be protected by insulating materials, as the column is the vital part of the roof support.

WHAT MAY HAPPEN.

It may erme to pass that, in spite of w’hat may have been looked upon as being principally a slowburning construction of the true type, buildings, such as machine-shops, are burned. A11 illustration shows the results w’here the stability of the props of the roof and floors gave way, with disastrous results. In such a case the vaunted fire-resisting construction proved no safety at all. That w’as exceptional, and it may happen sometimes that, as in the building illustrated (a big machine-shop property several hundred feet long, with but little of a combustible nature in its con-struction, except the roofs, windows and flooring,) such a method of construction w’as a positive disadvantage. If, however, the mill-const-‘cted style of building is strictly and conscientiously followed, each construction and equipment should guarantee, so far as is possible, the safety of a structure of that type.

In such a case as the one here illustrated, the absence of .automatic sprinklers and of firestops of the large areas in the shape of fire-walls, with fire-doors, would account for the total or almost total destruction of such a building. Areas are, of course, necessary for economical shop management; but they should not exceed the limit needed for safety.

W’HAT MILL CONSTRUCTION IS NOT.

The late Edward Atkinson, who may be looked upon as the father, as to the end of his life he was the staunch apostle of mill-construction, putting some up as follows, what such construction is not.

“1. Mill-construction does not consist in disposing a given quantity of materials so that the whole interior of a building becomes a series of wooden cells; being pervaded with concealed spaces, either directly connected each with the other or by eracks, through which fire may freely ass where it cannot be reached by water.

“2. It does not consist in an open-timber construction of floors and roof resembling mill-construction, but of light and insufficient size in timbers and thin planks, without fire-stops or fireguards from floor to floor.

SAW-TOOTH EXTERIOR ROOF WORK IN RE-INFORCED CONCRETE.

“3. It does not consist in connecting floor with floor by combustible wooden stairways incased in wcod less than two inches thick.

“4. It does not consist in putting in very numerous divisions or partitions of light wood.

“5. It does not consist in sheathing brick walls with wood, especially when the wood is set off from the wall by furring, even if there are stops behind the furring.

“6. It does not consist in permitting the use of varnish upon wood-work over which a fire will pass rapidly.

“7. It does not consist in leaving windows exposed to adjacent buildings unguarded by fireshutters or wired glass.

“8. It is dangerous to paint, varnish, fill or incase heavy timbers and thick plank as they are customarily delivered, lest what is called dryrot should be caused for lack of ventilation or opportunity to season.

“9. It does not consist in leaving even the best constructed building, in which dangerous occupations are followed without automatic sprinklers, and without a complete and adequate equipment of pumps, pipes, and hydrants.

‘‘10. It does not consist in using any more wood in finishing the building after the floors and roof are laid than is absolutely necessary, there being now many safe methods available at low cost for finishing walls and constructing partitions with slow-burning or incombustible material.

“It follows that, if plastering is to be put upon a ceiling following the line of the underside of the floor and the timber, it should be plain limemortar plastering, which is sufficiently porous to permit seasoning. The addition of the skim-coat of lime-putty is hazardous, especially if the topfloor is laid upon resin-sized or asphalt paper. This rule applies to almost all timber as now delivered.

“All the faults above recited have been committed in buildings purporting to be of mill construction, and all form a part of the common practice in ‘combustible architecture.’

“The foregoing description (adds the writer) of what slow-burning construction is not may be taken as a true description of what ‘combustible architecture’ is. It often seems as if the motive of this style of architecture had been to assure the most complete destruction of property by fire from the least and most preventable causes. Examples may be cited of what purport to be brick and stone churches, expensive residences and halls, of which the outer wall is only a sham, screening a very combustible wooden building, so pervaded by hollow wooden flues that in the case of fires, which often occur in the air boxes of furnaces and in the heating apparatus in the basement, the first notice is given bv smoke or flame from the peak of the roof.”

Newark, N. J., may appoint an additional battalion chief.

MILL-CONSTRUCTION OF TO DAY

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MILL-CONSTRUCTION OF TO DAY

MODERN MILL CONSTRUCTION.

When it becomes universally recognised that fire insurance is only another name for direct annual taxation for fire protection, and that it might be in great measure avoided—certainly might be measurably lessened, if proper attention were paid to the construction of buildings, then the desirable consummation of a sense of security, accompanied by diminished expenses and less irrecoverable loss—as fire-waste is— will be achieved. It could be arrived at within a few years, so far at least as concerns factories and warehouses, if slow-burning or mill construction were adopted. Its adoption, with the necessary modifications, might fittingly become the rule in the case of ordinary buildings, just as the steel construction and its accompaniments, internal and external, are ruling in the new office buildings and apartment .houses and in the case of some theatres, schoolhouses, places of public gatherings and entertainments and a few churches. Unfortunately, however, that rule by no means universally obtains, and in very many instances, especially in the construction of tenement houses, the buildings of today are too much of the firetrap and too little of the fireproof description. The result is seen every day in the destructive fires that take place all over the country, causing too often the sacrifice of valuable life. Probably not the least to be condemned are those which profess to be fireproof—those built of incombustible materials, and yet so constructed as to be open to nearly every possible objection. There are present the exposure-hazard, the non-separation of one floor from another, the abundance of non-treated wood for partitions, flooring, window-frames, doors and the like, the uninclosed elevator-shafts, the open spaces, the stairways, often of wood, built alongside of these shafts and stairways, the absence of sprinkler equipments where such would be necessary and useful, the unsafe arrangement of furnaces—in a word, the presence of everything that might tend to start a fire and help to spread its progress through the building. Till these details are looked after (and, as a rule, they are too commonly the things least thought of by architects, builders and property owners), we must continue to expect to hear of disastrous conflagrations taking place all over the United States. As a matter of simple prudence it would be well for the underwriters to insist upon architects and builders conferring with their inspectors before putting up a structure, which, although it may be in strict accordance with the local building laws, may yet be defective in some of the details to which allusion has been made—almost essentials, when viewed from the standpoint of fire protection. This is especially desirable in the case of factories, churches, public halls and theatres, school and tenement houses and business buildings. If this policy were adopted, not only would many an unavoidable fire and fire-loss be prevented, but, also, preferential insurance rates would be granted to those conforming to this method. The question as to fire protection and the extinguishment of fire, so far as concerns equipment, has been fairly well solved. Fire-pails and buckets, handextinguishers and small hose are looked upon as indispensable adjuncts, and have over and over again put out fires in their incipiency. Automatic sprinklers extinguish a very large number of fires, or, at all events, serve to keep them in check until the Underwriter steam or rotary pump or the outside fire apparatus completes the work. Steam pipes and roof hydrants form another means of internal protection—all to be supplemented by an auxiliary fire-alarm system, careful, sober and intelligent watchman making half-hourly or at least hourly rounds (to be checked by some of the various time-clocks in use), trained to the use of the minor apparatus, possessed of a knowledge of the location of each sprinkler-valve, so as to be able to shut it off in case of need or breakage or to see that it is in order before the factory is closed for the night, and an efficient private fire brigade, thoroughly acquainted with the use of the means of fire protection that are provided, and each member subjected to such frequent drills as will render it morally impossible for him to make any mistake either as to the work he shall do or the position he shall assume in case of fire.

MILL-CONSTRUCTION WHAT IT IS.

When the accepted fireproof construction of steel and brick or concrete is not adopted, mill construction should take its place. That method of construction consists in so disposing the timber and plank in heavy solid masses as to expose the least number of corners or ignitable projections to fire, to the end, also, that, when fire occurs, it may be most readily reached by water from sprinklers or hose; in separating every floor from every other floor by incombustible stops—by automatic hatchways, by incasing stairways and belts either in brick or other incombustible partitions—so that a fire shall be retarded in passing from floor to floor to the utmost that is consistent with the use of wood or any material in construction that is not absolutely fireproof; in guarding the ceilings over all specially hazardous stock or processes with fire-retardent material, such as plastering plain lime plastering only) laid on wire-lath or expanded metal or upon open dovetailed-lath, following the lines of the ceilings over hazardous places with sheet metal or other fire-retardent; in so constructing the mill, workshop or warehouse that fire shall pass as slowly as possible from one part of the building to another; and in providing all suitable safeguards against fire. The roof-spaces, especially in the case of hospitals, asylums, schools and hotels, should be utilised for sun-parlors and places for recreation,rest and play, not peaked or turreted or with dormer lights. These, besides rendering the attic story practically useless far occupancy, serve to interfere with the operations of the firemen and often to hinder the escape of the inmates. There is also a necessity for guarding against the spread of fire from one building to another across an intervening space, unless there are incombustible fire-walls and curtains and window-openings adequately protected. Such walls are pot infrequently omitted because of their first cost.

MODERN MILL BUILDING SHOWING WELL DESIGNED CONSTRUCTION FOR FIRE PROTECTION.

It may be added that mill construction practically presupposes the installation of an automatic sprinkler system, as in one of the accompanying illustrations. In a mill-construction building the floor should be of 3-in. plank,-grooved and splined, covered with i-in. top boarding, laid on timbers eight or ten feet on centres, has been made continuous—that is to say. without any breaks for belt-holes, open elevators or open stairways. Such a floor has never been burned through by a fire upon it or by fire passing through the floor above, except in a very few in stances. One was in a warehouse where a pile of jute bales took fire in the bottom tier where it could not be reached. The firemen then put water through the hole from below’. Fires on such mill-floors have been held not only in the building, but in the room where they originated. Again, iron posts have been crippled or sprung by heat a great many times at an early period in a fire. Wooden posts of suitable size have never burned off, until other parts of the building were already destroyed. They have in one instance resisted for hours fire which destroyed granite posts close by them by cracking and scaling—the granite measuring 12-in. x 12-in. In fact, the mill-floor, properly constructed and rightly guarded, has sufficed to hold fires not only in the building, but in the room in which they have originated until the mill fire department or the public fire department could extinguish the fire. The wooden mill-post of suitable size will last longer than the floor. The mill-floor possesses this very great advantage over the ordinary joisted floor. Fires may be readily swept away between the timbers either by sprinklers or by water from hose-pipes; while in the joisted floor the fire will burn on one side of the joist while the water is playing on the other side. Of the accompanying illustrations, one shows the exterior of a modern building of true mill construction, one wall being removed, in order to show its interior arrangement, the details of which have already been partly described, other details to be given hereafter. The other illustration shows its sprinkler-equipment, interior and exterior. In the pumproom are two 750 or 100gal. steam pumps of the Underwriter type, W’ith an 8-in. discharge pipe for each pump and the necessary connections. Each pump has one suction-pipe. The supply may be taken from a large reservoir, pond or river. When a good public water supply or large elevated reservoir cannot be available, a large tank, whose bottom is 25 ft. or more above the highest floor, is provided as shown in the diagram On the outside are shown the arrangement of the plugs,Tee and other, hydrants, including roof hydrants, controling circuits, indicator post gates, cotton conveyor-pipe to opening room in the storehouses, with their platforms dry-pipe valve on long bypass, and river for the sprinkler-service, pits, check-valves, gates, etc. Inside are seen the main mill, with its risers, heating flue, elevators, belt or rope tower, hose standpipe, closet-tower, fanroom, enginehouse and boilerroom (these last four off it. but connected) pickerhouse, dust receptacle and passage. It will be seen that stout fire-walls are erected inside, provided with standard firedoors at every fire-w’all and across the intervening spaces between the various buildings that do not form an actual part of the main structure. Wherever, also, there are windows, these should be of wired-glass in metal frames.

(To be continued.)