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Disaster led to stronger building codes in Xenia

Structures must withstand higher winds

XENIA | From the plains of Texas to the canyons of New York City, architects and inspectors are constantly looking for ways to make the built environment safer. But they can do only so much. Mother Nature always bats last.

Standard building codes call for a new commercial structure in this part of the nation to withstand lateral winds of 90 mph. If it's a residence of one to three units, the standard is 80 mph. (It could be 110 mph or higher in coastal areas subject to hurricane winds.)

That is sturdy for everyday storms, but it would have little deterrent effect against the black, swirling, counter-clockwise, upward-sucking motion of the monstrous 1974 tornado that hit Xenia.

Experts estimated the Xenia wind at more than 300 mph, making it one of the worst storms in a century. (It is scaled at F5 level, the maximum.) The damage was beyond any building code.

Still, preventive efforts continue. Since its latest big tornado in 2000, Xenia has adopted "slightly better" standards for new construction, said Don Shaffer, chief building official for Greene County.

"On new houses we add patented Simpson fasteners to each rafter or truss," Shaffer said. "In the rest of the county outside Xenia, it's every other truss." The metal tie is attached to top and bottom "plates," usually horizontal 2 X 4s, of a wall.

Shaffer said: "It's a slightly better standard, but I think we could do more." The fastener is designed to resist wind uplift, the official said, but it also can help a building withstand the non-spiraling, straight-line winds that may accompany a tornado.

"There's no perfect way to construct because tornadoes do what they want to do," Shaffer says. "It's been suggested we construct for 200 mph winds in areas we know are tornado areas." Recently, a Xenia IGA store had its roof "sucked right up, the airplane effect" by high, non-tornadic winds, he said. "High winds are something we can deal with."

Records of storms go back to the early 1800s. Even the Shawnee Indians, who called the Xenia area home, named it "the land of the crazy winds." Shaffersaid tornadoes are more frequent than people in these parts realize. Local records show 19 tornadoes in Greene County since 1884.

Building codes are local, but the trend is toward more uniform construction standards. Architect Terry Welker, chief building official for the city of Kettering, said the Ohio Building Officials Association has adopted an international residential code as a model code with higher wind-resistance requirements. The three major national organizations likewise merged their model codes in the past two years, forming an International Code Council.

So-called "safe rooms" are an option "well worth the money," Welker said. A safe room is usually constructed of masonry and steel to withstand very high lateral wind loads as well as any debris that might fall from above.

In Xenia in 1974, people who "did the right thing" — seeking refuge in a bathroom or cellar — sometimes died anyway when flying debris pierced the structure, or masonry from above collapsed inward, crushing them.

"Lots of municipalities are trying to pass codes that require safe rooms for different types of housing," said Joe Saliba, dean of engineering at the University of Dayton. A safe room can cost $3,000 to $5,000, depending on the design of a house or the site. It can be in a basement, on a grade-level slab. anywhere. Saliba says there is evidence that people survived F3- or F4-level tornados by taking refuge in a safe room.

Maury Wyckoff, chief building official of Montgomery County, predicts wind requirements will be strengthened in a revised code being drafted by the Ohio Building Officials Association and going into effect next year.

"There's been a steady trend toward safer buildings in my 26 years of practice," Wyckoff said. "But nobody has a code that's supposed to absorb a direct hit from a tornado at 200 miles an hour — except with a safe room."

"From an historical perspective, events like the Xenia tornado make a contribution to the development of building codes," Welker said. "The code community across the U.S. has finally begun to coordinate its efforts, with more requirements for inspections and licensing of contractors."

A catastrophic natural event, like Xenia 1974, also can be a lesson learned. A routine construction item like a windowpane can become a sword of decapitation in a storm like Xenia's. Even little Anna, in Shelby County, paid respect to its 1937 disaster, an earthquake, by making sure its new sewage plant, in 1996, was extra strong, according to village administrator Jon Hulsmeyer.

National Building Safety Week is April 4 through 10. They already know all about that topic in the land of the crazy winds.