How a wind tunnel that recreates hurricanes makes homes safer

It’s not easy to make a hailstorm. The scientists and researchers at the Insurance Institute for Business & Home Safety studied the phenomenon for roughly three years. At their 90-acre test site in Chester County, South Carolina, that’s dedicated to burning, shredding, and otherwise destroying test homes, the researchers wanted to simulate a barrage of frozen rain inside their five-story test chamber—all for the sake of learning how to build stronger and safer structures.

The first trial run didn’t work out so well. After working for months to figure out the correct wind speed, duration, intensity, and shape of hail—drawn and precisely modeled from extensive storm records—they needed to recreate the individual ice pellets. That’s not something you can do with an everyday ice machine. Researchers actually spent months creating special ice trays and freezing the pellets, only to discover that such a slow, deliberate method took so long, it made the test financially unfeasible.

After three years of research, the solution was more mechanical. Now, a series of 12 hail cannons, each with six barrels that can freeze and fire pellets at just the right terminal velocity and angle, hang from the test center roof. Lab technicians can control the guns to precisely mimic different kinds of hail, adjusting the downpour to match digital records of storms drawn from their extensive library, which contains everything from derechos to tornadoes to category-3 hurricanes.

“I play Mother nature,” says Julie Rochman, the president and CEO of the Insurance Institute for Building & Home Safety, who runs the test site. “I don’t play god.”

Rochman and her staff of engineers and scientists don’t play God for fun, however entertaining it must be to have routinely destroying and demolishing homes as a job description.

While the experiments at the IBHS test center are all about destruction, the end results are all about safety, specifically, how to strengthen homes to avoid the damage cause by wind gusts, storms, and wildfire, and help homeowners and businesses both rebuild and prepare.

This massive indoor test chamber, the only facility of its type in the world, is actually a long-term investment by the insurance industry. Even Hollywood doesn’t really blow up buildings like this anymore. Rochman initially thought special effects shoots might be a smart way to generate ancillary income for the institute, but every studio she contacted said they only demolish everything digitally these days.

Rochman likes to say 7,000 cocktail napkins died so that that building could live. Built in 2010, the $40 million facility has only been running tests for the last three years, since it took extensive research and study to figure out how to build a structure that can both simulate and withstand some of nature’s worst weather phenomena. But it’s all for a much more important cause: to help avoid the kind of cataclysmic damage that can ruin homes and communities (and cost the insurance industry a pretty penny).

“Once an area has experienced a loss, the community tends to be tuned in,” says Rochman. “There’s a period of time when people are looking for something to make their homes safer. Those that weren’t affected may also be reaching for the same thing. That’s where we want to step in. Here’s what we know that can make your home more resilient.”

Rochman is actually no stranger to destroying things for a living. At her previous job with the Insurance Institute for Highway Safety, she helped wreck cars and trucks to figure out how to design for safer vehicles and less injuries and fatalities. Over time, the IIHS proved successful at driving down vehicle damage and fatalities, which saved the insurance industry money.

Things were different on the home insurance side of the business. After a string of damaging hurricanes and storms in the 1990s and 2000s, the insurance industry said enough, says Rochman. Losses had been ramping up for natural disasters, and something needed to be done (the industry pays roughly $30 billion annually for insured property losses from catastrophes). Insurers can’t just jack up premiums (both due to the market and regulations), so why not copy the successes it had seen using research to improve automobile safety and do the same thing for property industry?

All images via the Insurance Institute for Business & Home Safety

“You need to break the cycle of destruction,” says Rochman. “It’s our business to pay for losses and drive those costs down. With the economy performing as it has lately, we haven’t seen the same returns with our investments, and you can only raise rates so much. The answer was, how can we make structures more resilient to Mother Nature?”

Hired to help set up the lab, Rochman has overseen the design and development of the unique research facility, which is situated on a rural site about an hour from the Charlotte airport. What other building do you know that has a team of asphalt engineers and its own detailed shingle library, or that employs a team of contractors whose job is to build homes meant to be destroyed? The IBHS is wired to its own power substation and has a 750,000 gallon reservoir for rain and hail. Wind, water, fire, hail, and aging are all simulated, charted, and tested on site. Beyond the test chamber, a “roof farm” composed of rows of detached, shingled structures sits under the Carolina sun.

The wind machine normally gets the most attention, and for good reason. The immense wall of fans took a year-and-a-half and $9 million to conceive and construct. On one end of the structure, 105 industrial-strength fans, normally used for ventilating mine shafts, are stacked in a series of cells which can be controlled and manipulated individually to recreate the gusts, howls, and bursts of any number of weather patterns. Inside the chamber, the wind speed can be raised or lowered by 30 mph in just seven seconds. Often, pieces of the homes that are blown out the back door of the test chamber end up thrown against the trees behind the building.

“These fans are made to run 24 hours a day, but we stress them in ways they weren’t meant to be used,” says Rochman. “We had to figure out how the wall of fans won’t shake itself apart.”

All of this power, Rochman says, is meant to “do research that changes the world.” The Institute informs and helps improve building codes, but since just 2-3 percent of the existing structures were built over the last year, that can be a slow way to improve the safety and stability of the built environment.

The IBHS main mission is to use its findings to develop what it calls FORTIFIED Standards, different levels of extreme weather protection system upgrades (bronze, silver and gold) the progressively improve the safety of a building (bronze focuses on roof reinforcements, silver includes stronger doors and windows, etc.). There’s no way to completely protect against everything the environment can throw at you, but precautions can make a big difference. Institute research suggest that if just the roofs of buildings within the country’s hurricane zones were strengthened and fortified, Americans and the insurance industry reduce potential damage by 40 percent. That area includes an estimated $11 trillion of insured property.

Rochman and her staff take the job pretty seriously, she says. But that doesn’t mean they don’t enjoy their work. Amid the shredded frames and faux storms, she says she likes the wildfire testing the best. Wind is normally an invisible force, but with embers dancing through the air, you can see the swirls and patterns of nature, a language her staff spent considerable time trying to learn and recreate.

“There’s probably a little pyro in me,” she says. “When the embers are in the wind, it’s a little scary and gorgeous. I’ll never forget the first time we did the test. We had some fire chiefs observing, and at one point, they were jumping up and down screaming, ‘That’s just what it’s like in the real world!’”