Saving Lives: ICFs and Tornados

Over 1,000 tornadoes touch ground in the US every year, leaving a path of devastation as they scatter people’s lives across the countryside. This year has seen the deadliest tornado season since 1953. Already, 519 People have lost their lives and billions of dollars of damage was caused as twisters ripped through parts of Oklahoma, Arkansas, Kansas and Missouri. The magnitude of the devastation has people questioning current building practices and looking for alternatives. Many are turning to ICFs to provide protection from extreme weather conditions.

Fort Pierce is home to one of Florida’s “Hurricane Houses.” The 3,000 square foot centre is one of 4 storm mitigation centers launched in 1997 to provide safe haven for Florida residents. When Hurricane Francis whipped its way through the area in 2004, the 115 mph winds caused extensive damage to buildings in the town, but the Hurricane House remained largely unscathed and provided a safe shelter for many of the town’s residents. The house was built using advanced building technologies including ICFs. ICFs provide a Styrofoam shell, reinforced with rebar, into which concrete is poured. ICFs are not only engineered to withstand excessive force, they also provide the home with a more energy efficient envelope. The Federal Emergency Management Agency (FEMA) recommends the use of ICFs to protect residents from flooding and high winds associated with tornadoes and hurricanes.

The Hurricane House is not the only example of the virtually indestructible ICF homes withstanding inclement weather. When 95% of Greensburg was destroyed by an F5 tornado, and the other 5 % severely damaged, residents decided to let the town live up to its name; they committed to rebuild the town to be as environmentally friendly as possible. ICFs have featured strongly in the rebuilding efforts. “ICFs are a great choice for rebuilding,” Says Curtis Nickel, a local ICF contractor; “ICF has an R-value that’s consistent and will be there forever. The concrete cures to 125% of design strength. It can take a 250 mph winds.” Concrete also contributes 19 to 28 LEED credits as the town strives for LEED platinum status. The list of ICF buildings in the town continues to grow and 3 churches, the city hall, a grocery store, a bank, at least two office buildings and several homes have been rebuilt using ICFs.

You can watch a documentary series on the rebuilding of Greensburg by Leonardo Di Caprio by clicking on this link.

How reliable are ICFs? Since the building technology is so new, can they be trusted to withstand the flooding and winds of major storms? Several studies have been conducted to test the resistance of ICF concrete walls. A recent study at Texas Tech University tested the resistance of various wall assembles to flying debris by shooting 2 x 4 wood slats at the walls at a speed of 100 mph. Wood and steel stud walls were no match for the simulated flying debris. The slats didn’t even leave a mark on the ICF walls. The study had high praise for the durability of concrete walls: “The strength and durability of concrete walls offer unmatched resistance to the devastation of major storms. Concrete homes are less likely to suffer major damage from debris than conventionally framed homes. This greater measure of built-in safety makes cement-based ICF construction systems the quality choice for your new homes.” ICF walls are more resilient than other methods of constructing concrete walls due to cure time and the monolithic structure of the walls. Watch the Texas Tech below:

Amvic Insulated, manufacturer of ICFs, conducted their own tests in June 2003. Have a look at the amazing results in this video:

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