encoding design

Looks promising, doesn’t it?1951 code cover

In Chicago for this weekend’s Chicago Design Conference at the Art Institute, presenting a rabbit-hole of research on Chicago’s 1951 Building Code, which is a great story about how political and economic considerations end up being imprinted–literally ‘encoded’–into buildings through these documents.

The city’s code through WWII had been a ‘specifications’ code, one that held architects and builders to strictly defined materials and dimensions depending on the level of fire resistance a building type and location demanded. This worked well for an era where brick, concrete, stone, plaster, and terra cotta were pretty much the only materials being considered for building exteriors and walls.  But technical developments in the 1930s and, especially, during the war meant that the code left a lot of innovation on the table, with no way for designers to take advantage of new materials like, say, aluminum in skyscraper construction.  Or new production techniques like gypsum drywall in residences.

John O. Merrill was the choice of a coalition of civic leaders to put a new code together.  They had hired the John Pierce Foundation to prepare a study of new types of building code, and the Foundation was familiar with Merrill’s work on the extensive housing constructed for Oak Ridge, Tennessee–which because of wartime exigencies had been largely unregulated and, therefore, particularly innovative.  Merrill and his team put a draft code together in 1948, and it spent two years in limbo as building trades, manufacturers, developers, and politicians argued over its merits.

The full story is in  the conference paper here, but suffice to say that the proposed code served as a lightning rod for everyone who had a stake in the changing nature of high-rise and domestic construction.  Labor-saving technologies like drywall drew the ire of tradesmen and their unions, who used fears about fire to bolster their arguments against such threats.  Developers and other trades–in particular carpenters, who stood to benefit from relaxed standards for frame construction–lined up in favor of Merrill’s code.  Ultimately, after controversies, an underhanded attempt to sneak 25 amendments in without the public noticing, and a brokered compromise by new reformer mayor Martin Kennelly, the code passed on New Year’s Eve, 1949.

Among other things, the new code’s relaxed standards eliminated tight specifications for spandrel walls in high-rise construction.  The old code had dictated upstand walls between windows, assuming that all skyscrapers would have more or less solid skins with punched windows:

“Every window in a non-combustible wall shall have a non-combustible sill and spandrel wall equivalent in fire-resistive value to two-hour fire-resistive construction for a vertical distance not less than three feet between such opening and any opening in the story next below such opening.”

The new code required structural elements to maintain a three-hour fire rating, but loopholes in definitions and classifications left no such requirements for the remaining territory of any non-bearing exterior wall that faced a street or a court.

The result can best be seen in Mies van der Rohe’s first two projects for developer Herbert Greenwals–Promontory, which was completed in 1949 to the old code’s spandrel standards, and 860-880 Lake Shore Drive, which was permitted after the new code took effect, and which took notable advantage of the newly-freed exterior wall:

Encoding Design Slides Nov 2018 Promontory 860.001

The code linked construction downtown and development further afield in balancing concerns for safety with innovation and the political power of unions and developers against one another.  As such, it’s one of several precursors I’m looking at in trying to figure out how innovative high rise construction took root in the city some twenty years after development ground to a halt during the Depression.  Codes are always political documents, but this episode illustrates this brilliantly.

Thanks to colleague and office-mate Andrew Gleeson for pointing me in the direction of numerous assessments of Promontory’s spandrels–theories on them have ranged from lack of steel to a conservative building culture, but the impact of the code’s restrictions seems to be a new piece to add to the puzzle.

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