Inspection of Old Buildings.

Inspection of Old Buildings.

T. R. TINSLEY, PART 11.

These old buildings that speckle our cities, like veritable freckles on the municipal complexion, are as full of menaces as a cellar fly is of maggots. The particular menace that will be referred to here is the jeopardy to life, limb and property, by reason of their great susceptibility to the effect of fire and water.

The official inspection, suggested for ascertaining the status of the ravages of eremacausis and concomitant corrupting agents, of the wooden structural of these old buildings, might, as a primary rule, only comprehend such vital points of these timbers as the bearing ends resting on walls or girders, the head and base ends of columns, posts, braces or struts, or as these parts can always be easily reached with comparatively no expense to occupant or inspector. Initial tests can be made by puncture of awl or drilling by small auger and scrutiny of the boring dust by smell, taste, weight, microscopic or chemical action, or by any method, the result of direct practical research, to obtain this end. Such a primary survey would produce relevant evidence, trustworthy for intelligent procedure. The official finding of such an inspection should become permanent record of the building department, and in case the finding developed a state of decay threatening the safety strength of these structural timbers, official notice should lie served on owner and occupant and a copy of the record filed with the fire department, as a measure of public safety, as the duty of firemen does not comprise entering death traps. It must be borne in mind that no inspection can arrive at a true finding or verdict unless it embraces the conditions that these diseased timbers would present under a degree of heat dose to the igniting point.

HEAD GATES OF FLUME, POWER HOUSE AND SMELTER, GREAT FALLS, MONT,

The effect of heat and cold on wood is the reverse of the same on metal, since cold lengthens wocxl and heat shortens it. The building of the ends of joists and girders into newly laid up brick or stone walls, where they are subject to absorb the freshly burned lime in liquid state from the mortar, greatly hastens their decay at these vital points.

Both law and practice, obtained among the ancients and our forefathers, governing the cutting of trees in the leafless season, yet progressive, we (?) supply the market demand irrespective of sap status, and we must dearly pay the piper therefor. The underwriter’s practiced eye is perchance keen and observing, but it must be superficial withal. To demonstrate, some few years ago the head of a famous female academy called into service our office for an inspection of the condition of the floors of their huge building. Her fears had been raised by the accidental lifting of a floor board next to the wall while in search of a lost coin. Some one remarked that the joists scarcely rested on the walls. Upon a thorough examination, a most startling condition was uncovered. The joists supporting the floors of almost the entile school rooms did not average quite one-half an inch bearing on the girders, and less than one and one-half an inch on the brick walls. Evidence of severe shrinkage, of eremacausis and other putrescent constituents, was plain and plentiful. Now, beyond the peradventure of a doubt, had n fire taken hold strong enough to generate sufficient heat to raise the temperature of these joists to a degree just short of ignition, they were in no condition to withstand the pyrogenous strain, and disaster would have resulted.

A peculiarity worthy of mention in this connection, is that after these floors had been made safe, insurance policies held previous to the discovery and remedy, and which expired immediately thereafter, were renewed at the same risk, and new policies taken out in companies not before holding, were written at the same risk as those taken before this uncanny state of affairs was exposed, yet these underwriters were made fully aware of the true conditions of things, and to remonstrance they simply replied that had they known of the existence of such a condition they would have refused to write a policy. But why didn’t they inspect intelligently and know.

Another case w*as that of a large mercantile building five stories high in the very centre of the city, specially designed for heavy floor work, but, being run up with a rush, its structural timbers were hewn from the leafed stem and set up in place in cold weather, and inside of ten years shrinkage, dry and wet rot, oxidation, microscopic organisms and other putrescent agents had rendered these timbers diseased and prematurely old. A fire broke out in the basement ; there was but a moderate bulk of goods stored there. The firemen responded promptly, when, without fair warning, the first floor gave way immediately over the fire area below.

And soon after the other floors above this space came, one after the other, until the roof followed suit. Of course, the smoke, compressed air. fire, sparks, etc., of these falling floors baffled the firemen and accelerated the fire.

Afterwards, while having the debris removed from this basement, these first-floor joists were found to be only partially charred, and evidences remained where in a number of cases they had broken abruptly near the wall line. Upon inspecting the unburnt apartments of this building a very similar state of affairs was found as existed at the academy.

There can exist no doubt but that had this first floor been what it should have been, and was thought to have been, it would have confined the fire to the basement sufficiently for it to have been controlled by the firemen.

Now, again, after remedying all these evils and putting this building in strong condition, the insurance policies were issued as the same risk as when this structure was pregnant with dis aster from fire and water.

And it was explained that this was considered as the same risk simply because the underwriters had assumed that the building was in good strong condition when they had written the previous policies.

Again I pause to ask, why assume anything? Why not know by proper inspection ?

Inspection of Old Buildings.

1

Inspection of Old Buildings.

A word to the readers of FIRE AND WATER as to the inspection of structural timbers of the old buildings with which our cities are more or less sptinkled.

The character of construction of these old buildings, together with the severe action of our climate on them, renders these structures prematurely old in all respects before time has aged them. Duplicate any one of them in Italy or Spain and in fifty years it will not show as much decay as it does here in twenty.

The old buildings I refer to are in active service in our cities, and are in the midst of modern and more expensive structures. They harbor a menace that should demand special official inspection. It is the progress that cremacausis has made in the timbers.

What percentum of the original strength of these wood structurals has been destroyed by the process of oxidation, that slow burning of the cellular tissue, by the action of air and moisture ?

What is the true condition of fibrous resistance remaining ?

There can be no doubt but that joists, rafters, girders, posts, etc., when sufficiently oxidated, become more susceptible to fire, both as to ease of ignition and rapidity of combustion. This is a sequence of the nature of the oxidizing power of air and moisture accelerated by the ravages of infinitesimal insects or “ microscopic organisms,” as Pasteur is pleased to term them. The effect of this biolytic alliance is the destruction of cellular tissue, the reduction of atomic constitution, the product of this being the presence of a highly inflammable dry powder and an increased porosity of the timber, both essentially sensitive to heat, as they also are correspondingly destructive of inherent strength.

Now the menace referred to lies not in the mere cremacaustical saturation alone, as it is known that timber so affected, while retaining its normal temperature, scarcely ever is permitted to reach that degree of decay when it will collapse, like the wonderful one-horse shay. But this self-same timber, which in normal temperature is not condemnable according to our present mode of inspection, when subjected to the absorption of heat, and consequent rapid increase of temperature, passes into an entirely different condition, its mutilated cells and diseased fibrous tissues which, under normal temperature, present a rigidity of resistance astonishing. Such resistance is dispelled when they are under a high temperature, because the internal leverage and strain of this penetrating heat demoralizes, if not demolishes, their form-strength, and as the heat intensifies this push and strain increases until it produces a degree of enervation in fibrous structure, that should an inspection be made, while in this state, the uncondemnable would be condemned as unsafe.

The application of water to wood, thus diseased, is somewhat similar in effect to that of heat, and especially so when the wood is carrying a high degree of temperature at the time svater is applied. Firemen have often remarked the suddenness with which roofs and floors of these old buildings go down during a fire, and it has puzzled many of them, as the building was in active service, was considered safe, and insurance worthy, and its several floors were loaded with valuable merchandise, perhaps its apparent strength had been a boast.

Yet the fire had scarce got a good hold, when, without a fair warning, the collapse came. Now in most cases, the simple explanation is that the timbers were diseased, as above stated, especially at their vital bearing points, i. e. -. the ends of joint, rafter and girder that are built into the wall, and the base of the supporting posts or columns, as at the joints these timbers are more subjected to the baneful effects of air and moisture, and consequent penetration and creation of ravaging insect life.

During two terms as chief of the building department of Kansas City, occasion was frequently presented of observing most conflicting evidences of decay in timber of buildings condemned and being torn down. Timbers that, to the -eye and touch, seemed lair and faultless, when submitted to microscopic scrutiny, developed a deplorable state of structure, and when two similar pieces, one normal temperature, the other heated almost to the igniting point, were tested as to their relative breaking strength, it was the heated one that always more readily yielded. Tests were made also as to the susceptibility of fire and product of smoke between equal pieces, one of the diseased old wood, and one of new but well seasoned sound wood. In all cases the old piece showed readier ignition, hastier combustion, and less smoke product.

It is well to remark here, that sometimes timbers were met with, in the demolition of these old buildings, that were sound and faultless, but they certainly were the exception. In an official inspection of the structural timbers of these old buildings, the practice should obtain of establishing by simple practical tests, the extent to which wood may be inoculated by this disease, and when heated to the degree of ignition, still retain a sufficiency of strength for purpose required. And all structural timbers having the decay or disease to that extent tlia. they will not possess a safe strength when so heated, should be condemned, and either replaced or reinforced so as to ensure safety.

THE CONVEYOR IN OPERATION.

Many valuable lives have been lost beneath walls suddenly hurled down by the force of air compressed, or pried over by the ends of timbers built in by these collapsing roofs and floors let loose by this action of heat on decay, whereas proper inspection would have averted this.

All buildings are subject to fire and water at any moment. Certainly then, the test of strength applied to them, in the name of public salety, should fully meet the emergencies.