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Construction History: A Detail Fails

In the world of US building design and construction, the last quarter of the nineteenth century and the beginning years of the twentieth were largely a search for “fireproof” construction. Ultimately that search proved to be futile, and the efforts switched to timed fire-ratings and the protection of people via better egress and other non-structural means, but in 1904 the focus was firmly on how to make buildings fireproof. Part of the effort was revisiting long-held ideas about fire protection by examining buildings after fires. There was no shortage of major fires in the era, including the 1904 fire that destroyed much of downtown Baltimore.

The picture above gives a sense of what happened to flammable buildings – in this case a house or house-sized commercial building with wood-joist floors – during the Baltimore fire. There no longer is any interior to the building and the rear wall (the far side from us) seems to have collapsed, giving us a view of the neighbors by looking in the front windows. And chunks of the front wall have collapsed as well, turning the two vertical lines of windows into two continuous masonry openings. This building has been reduced to two and a half free-standing walls. The caption mentions the specific piece of fire-prevention technology that was one of the subjects of the journal article: fire-proof shutters.

When studying past technology, you have to get into the mindset of the people who used it, rather than viewing things from our time, in order to fully understand how and why it was used. I have always found it difficult to understand the mindset behind fire shutters, because, to me, they don’t make sense. If the fire is in a neighboring building, you can close the shutters of your building (assume the pintle-style hinges aren’t rusted or painted stuck) to keep the fire out. So far, so good. In the process, you just closed off a non-negligible amount of the light and air entering your building. Much worse than that, the iron of the shutters is going to get hot – possibly red-hot – and it’s immediately adjacent to your wood window frames. So the possibility of the shutters themselves starting a fire in your building is not small, and if the iron of a shutter warps, as it tends to when heated only on one side, it’s going to be a funnel sending hot air at the window behind. The shutters in the small building above didn’t save it, but then again nothing was going to save a small wood-joist building in the middle of a fire-storm. What about bigger and fire-proofed buildings?

Here are failed shutters at buildings that survived structurally intact:

That last picture gives a sense of the destruction: the hill in the foreground used to be the rest of the building on the far left.

Fire shutters did not survive in modern codes because the evidence showed they did not work as intended, to keep fire from entering a building through its windows. You can still see them on old buildings, usually on the rear facades, open and tight to the brick on either side of the windows, because no one ever went around removing them. We just, as a society, stopped pretending that they meant much.

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