Debris driven by high winds present the greatest hazard to homeowners and their homes during tornadoes and hurricanes. Laboratory testing at the Wind Engineering Research Center, Texas Tech University, compared the impact resistance of a variety of residential concrete walls to a sample of conventionally framed walls. According to the results, the frame walls failed to stop the penetration of airborne hazards. However, the concrete walls successfully demonstrated the strength and mass to resist the impact of wind-driven debris.
Various wall specimens were impacted with a 2x4 wood stud traveling up to 100 mph. This is equivalent to the weight and speed of debris generated during a tornado with 250 mph winds. This testing covers the maximum wind speed generated in 99% of U.S. tornadoes.
Ten wall specimens were constructed, each representative of the type of construction now used to build frame homes and concrete homes in the United States. Table 1 describes each wall assembly tested.
The Wind Engineering Research Center's compressed air cannon propelled a 2x4 wood stud debris “missile” at the test walls. The stud was propelled along its axis with the leading end hitting the specimen. Electronic timing devices measured the speed of the debris as it traveled from the cannon to the test walls located 16 feet 6 inches away.
Frame wall performance
The frame walls lacked the weight and mass to resist the impact of the wind-driven debris. In each case, the debris traveled completely through the wall assembly with little or no damage to the “missile.”
Concrete wall performance Co
The concrete stopped debris from traveling through the walls. Exterior finishes were damaged, but the concrete walls were unscathed. Even the narrowest, 2-inch-thick “waffle grid” ICF wall was undamaged by the direct impact of the debris at more than 100 mph.
Damage from hurricanes
Hurricane winds will be less than the equivalent maximum speeds modeled in the tests. Missile testing designed to mitigate property damage losses from hurricanes use a criterion of a 9-pound missile traveling about 34 mph.
The strength and durability of concrete walls offer unmatched resistance to the devastation of major storms. Concrete homes are less likely to suffer damage from debris than conventionally framed houses.