In the annals of Chicago history, there is a marvelous urban legend about how John Van Osdel had buried his drawings in the basement of the construction site of the new Palmer House in an attempt to preserve them from being destroyed by the 1871 fire. To his astonishment, when he returned to recover them, they had survived the holocaust completely intact. The legend goes on to credit this experience with Van Osdel coming up with the idea to fireproof iron columns and beams with fired clay coverings. Highly romantic, and complete fiction. The actual story of Chicago’s invention of terra cotta fireproofing is as follows:
The call by the National Board of Underwriters following the 1874 fire, to stop the use of cast iron columns and substitute them with the use of heavy timber columns was a direct threat to Nathaniel S. Bouton’s Union Foundry Work’s structural iron business, pressuring him to take an active role in the development of a fireproofing system for iron framing. Unfortunately, the recession and resulting slowdown in construction during the latter half of 1873 had forced George H. Johnson, to close his fledgling fireproofing business in Chicago and return to New York early in 1874.
(In Volume One we saw how Johnson, an architectural designer with Daniel Badger prior to the start of the Civil War, had developed an interest in fireproofing buildings, first by inventing a system of hollow clay tile blocks that was used to construct fireproof grain bins in grain elevators.
Although Johnson held the patent, he needed expertise in the manufacturing of fireclay products. My research points to Johnson collaborating with New York’s leading fireclay producer, Balthasar Kreischer. Kreischer had been born in 1813 in Bavaria to a father who was a brickmaker. Following the 1835 New York fire, the twenty-two year old immigrated to the U.S. in hopes of finding work with his talents. Within ten years he had uncovered beds of clay needed to make fireclay for baker’s ovens and bricks to line fireplaces. There was no one more able in New York in 1869 to produce Johnson’s newly-patented clay tiles than Kreischer.
Stimulated by his interest in such systems, Johnson apparently had traveled to Paris in 1870, just prior to the start of hostilities with Prussia, to study the latest developments in fireproof floor construction. Johnson coupled this new information and with Kreischer’s experience of clay manufacturing they addressed the problem of fireproofed floors. The two patented (#112,926) a hollow tile floor system on March 21, 1871. Johnson and Kreischer’s system consisted of a monolithic terra cotta piece or pot that spanned between two beams. The design that was almost identical to the system patented by Frederick Peterson some sixteen years earlier and used in the Cooper Union with which Johnson had personal experience as he was Badger’s chief designer for the building.
However, the monolithic nature of the design is curious in that the majority of patented French systems, that had been exhibited during the 1867 Paris World’s Fair and that Johnson would have seen during his trip, incorporated segmental arches and had been in existence at least five years prior to his trip. The story becomes even more curious as Kreischer returned to the Patent Office later that same day and patented (#112,930) without Johnson the same system, except that it incorporated a three-piece segmental arch.
Nonetheless, the date of these patents prove that these two New Yorkers had applied fired clay as a fireproofing material for floors long before the 1871 fire. So New York, and not Chicago had spawned the initial idea of using fired clay tiles for the construction of fireproofed floors. The two went their separate ways, Kreischer starting a company in New York, while Johnson had moved to Chicago to take advantage of the rebuilding effort, founding a company that eventually supplied his floor tiles, that also employed multiple tiles for the Kendall Building.)
Johnson’s departure from Chicago in early 1874 had left a large void in the city’s collection of experts on fireproof construction. Bouton, therefore, had turned to Peter B. Wight for assistance in developing a technique of fireproofing cast iron columns in order to save his business. Wight and his partner William Drake wasted little time in beginning to experiment after the July 14 fire with timber as an insulating material for cast iron columns. Wight’s use of wood to protect iron should not come as a complete surprise, for following the 1871 fire in Chicago and the 1872 fire in Boston, many observers had begun to champion solid timbers as a total replacement for iron construction, that was only reinforced by wood’s lower cost. In the latter part of August 1874, they attempted one of the earliest recorded tests of the ability of hard, slow burning oak to protect cast iron, by exposing three different types of columns to a controlled fire.
Their protected column employed a cast iron column with a cruciform section with an outside diameter of 10.” This was encased by four pieces of red oak that were attached to the column by recessed plates and screws. Wrought iron battens covered the joints between the pieces of wood. Plaster of Paris was then poured in from the top of the assembly to fill all of the gaps between the metal and the wood. The other two columns that were to be tested were not protected; one had the same cruciform section while the other was a 9″ diameter hollow cylindrical section. The test procedures did not maintain an intense heat for a long enough period of time, however, so the test results proved somewhat inconclusive. Nevertheless, Drake and Wight (I believe that although Wight was the expert on such issues, the two partners listed their names alphabetically in the patent application) were granted a patent (#154,852) for this assembly on September 8, 1874. Symbolically on October 8, 1874 (the third anniversary of the 1871 fire but more importantly, only a week after the insurance companies began to cancel insurance policies), they ran a successful test at Bouton’s Foundry. After a one-and-a half hour exposure to an intense fire, the wood-encased column survived with only a slight charring of its surface while the other two columns had completely failed.
Wermiel, Sara E. The Fireproof Building: Technology and Public Safety in the Nineteenth-Century American City. Baltimore: John Hopkins University Press, 2000.
(If you have any questions or suggestions, please feel free to eMail me at: firstname.lastname@example.org)