NOVEMBER 2012 IN
RICK ASTER’S WORLD
Designing Water-Safe Buildings
Most cities are in river valleys and coastal plains, and most buildings are in these cities. A consequence of this is that a frightfully high proportion of buildings are likely to be in the water at some point, the result of storms, climate trends, tsunamis, and broken pipes. It is something of a mistake, then, that buildings are designed on the assumption that they will remain above water. The work of reclaiming a building from flooding can be nearly as expensive as the original construction, yet this cost could be greatly reduced with changes in the design of buildings so that they tolerate water better.
In no particular order, these are some of the design themes that represent weak points in a building when it comes in contact with water:
- Untreated wood as a structural material (especially in posts, beams, and subfloors). Wood weakens, deforms, and decays on contact with water. The use of a structural material that is lighter than water ensures, when the water gets deep enough, that the building will come apart and float away. Heavier materials, such as steel, cement, masonry, tile, and glass, are more easily made to resist water.
- Locating the electrical service point near or below ground level. Tradition and building codes often require that an electrical service panel and the most essential wiring is located in the basement of a building. Unfortunately this shuts off electricity in even a minor flood that otherwise may not require a building to be evacuated. It would be no more expensive to move the focal point of electrical service several meters higher, or to the attic. Designs incorporating low-lying electrical service points caused most of the lingering problems from flood damage in lower Manhattan last month, and of course, led to the nuclear power disaster in Fukushima.
- Basement server rooms, storage rooms, generators, etc. When the layout of a building places essential equipment or expensive supplies at the bottom of a building, it magnifies and extends the damage caused by the smallest amount of flooding. In New York City last month, hundreds of buildings that had backup generators remained offline for more than a week simply because the generators were located in the basement. Similarly, web sites were down for a week because server rooms were in flooded basements. The traditional shop design locates the main inventory at street level and any extra below ground, maximizing the loss when water levels rise.
The added costs of these adjustments are minor when compared to the costs of restoring a building after a flooding event, not to mention the potential for loss of life when buildings come down in a flood. When you look at buildings located in places that can expect to flood every 25 years, or more often, there is little reason to stay with the traditional building designs that aren’t designed for a world that also contains water.
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