If, indeed, the fire of 1871 had only a minimum impact on post-fire Chicago’s architecture and construction, it could be said that the most important result of the 1871 fire on the city’s architecture was the relocation to Chicago, of New York City’s leading expert on fire construction, Peter B. Wight. Once things had settled down following the end of the fire, local architect Asher Carter of Carter & Drake, contacted Wight in New York and offered him a partnership in the firm if he would come to Chicago to help with the overload of projects he anticipated from the imminent reconstruction. Carter had first become acquainted with Wight back in 1858, when the then twenty year-old architectural apprentice had spent a year in Chicago, 1858-9, designing a small office building for one of his father’s friends at the southwest corner of State and Randolph, and had maintained correspondence with Wight after he had left. William H. Drake was also not a stranger to Wight at this time. Drake, along with Sanford E. Loring, had been made a Fellow of the A.I.A. in 1869, in order to increase the size of Chicago’s chapter to three (John C. Cochrane had joined earlier) that was the minimum size required to officially form a chapter, which was done on Dec. 13, 1869. Wight was the national secretary of the A.I.A. in 1869 and therefore, would have corresponded with all new members.
Wight traveled to Chicago three weeks after the fire in late October 1871, and visited for three days finalizing his contract, locating a residence, and observing the destruction. Upon returning to New York to prepare for his move, he was asked to present his observations of the fire to the 1871 A.I.A. National Convention, held in Boston on November 14-5, 1871. He listed five factors that contributed to the scale of the destruction:
1. The walls of the buildings were uncommonly thin in proportion to their height, being only 12″ thick above the first floor (we have seen that this was sanctioned, however, by the building code). He consistently hammered this point home by citing numerous examples of specific building failures such as the Chicago Tribune Building. He observed that the fire’s intensity appeared to have diminished where the few walls that still stood remained, giving credence to the fact that had Chicago’s walls been thicker, the fire’s advance might have been slowed considerably.
2. The materials in the thin walls did not perform well. Brick walls performed better than stone (as the code had tried to make allowances for), but even many brick walls failed because they were often built with soft brick fillers. He condemned stone walls outright, especially stone veneers, as being extremely vulnerable to the intense heat and totally useless as a fireproof material. Almost without exception, every type of stone had spalled or cracked completely. Much of the stone used in Chicago was Lemont limestone that had exploded upon contact with the heat. Wight had amused his audience by comparing its reaction to heat to that of popcorn.
3. Iron shutters on windows (required by code) were either non-existent or had not been closed. He attributed the destruction of the otherwise well-constructed U.S. Post Office and Customs House to the fact that while it was equipped with shutters, one appeared to have been left open, exposing the highly combustible materials of the interior to the heat of the fire. He went on record claiming that the building would have survived the fire intact had the shutter been properly closed.
4. Exposed “fireproof” iron performed very poorly in the presence of the extreme temperatures:
“A. Wrought and cast iron beams gave way very quickly. As mentioned previously, fireproof floors were constructed in Chicago prior to the fire, being either brick arches or concrete covered corrugated sheet iron arches. Both of these flooring systems performed extremely well. The Achilles heel of the systems, however, was the exposed bottom flange of the iron beam, which often sagged due to the loss of rigidity caused by the high temperatures.”
“B. Much of the devastation was the result of cast iron columns failing in one of the three aforementioned manners. No matter which mode of failure prevailed, the result was the same, the collapsing of sound, intact floors that were supported above the column. Wight cited the loss of the Post Office and Customs House as a prime example. The fact that this type of column was allowed by the building code, let alone used by knowledgeable architects is perplexing, for there were many examples of failures of this type of construction in England that should have shown the vulnerability of such construction. Also, as has been pointed out before, New York was requiring the use of double-walled, plaster-insulated columns by this time. Wight was queried on this point after his talk to which he replied that he specifically raised the issue of this type of construction, to which he found no evidence either that the column was used or that it was even known about! He suspected with good reason that these “relatively expensive” devices would not have been employed in the cheaply constructed “fireproof” buildings of a Chicago speculator/owner.”
“C. The practice of stopping a bearing wall at the first floor by supporting it on an iron beam, truss and/or column in order to open up the first floor proved to be the condemning flaw in many buildings once the iron member was subjected to the heat.”
5. The roofs were perhaps the most insecure parts of the buildings. Many were covered with tar and gravel that appeared to have encouraged the fire in the face of the tremendous downdraft produced by the fierce winds that fed the fire and the corresponding updrafts of the intense heat.
Wight then went on to recommend possible solutions and practices that could eliminate most of the hazards and potential problems that led to the scale of the Chicago Fire. These can be seen not only as the “state of the art” from a contemporary expert, but even more so as a prediction of things to come.
1. The Importance of a good, solid wall running the entire length from foundation to roof, that he considered the best construction for a fireproof building. He recommended to avoid the use of iron storefront systems in the first floor that supported bearing walls above.
2. What value was a good wall whose windows were not protected? “But by all means keep out the fire from neighboring buildings, even if you have nothing in your own house to burn.” Therefore, he recommended that all windows should have fireproof shutters, including the front (the usual practice was to locate these only on the rear windows).
3. He insisted that the roof be the best-constructed part of the building.
4. He also addressed the problem of protecting ironwork.
“I was struck with one fact in connection with the use of rolled iron beams, and it was, that the beams often sagged before the filling gave way; and I was impressed with the idea that precautions should be taken in fire-proof buildings to protect the underside of the beam, so that the heat cannot affect the stability of its lower flanges. The lower part being exposed, absorbed the heat, and the beams consequently sagged very often. I would direct the inquiries of the Institute to the propriety of covering the lower parts of the iron beams with cement, artificial stone, or terra cotta, or perhaps to the advantage of plastering the ceiling underneath the iron beams. All the buildings with iron beams that I happened to see, were without any plastering underneath, except where the soffits of the brick arches were plastered.”
Therefore, Wight had proposed a radical revision in fireproofing strategy from the existing practice of assuming that a building was safe if its interior construction could not support combustion (i.e., Bogardus’ claim for cast iron) to one that bears the experience of a major urban holocaust. The danger loomed not from within, but from without. The best fire protection for an urban building, therefore, was a fortress of brick walls and a solid roof, not dissimilar to those of a Renaissance palazzo.