While no one can control the weather, we do have control over building practices.
Hurricanes are the destructive force of nature that Florida expects each fall much like we in Oklahoma expect tornadoes during the spring. In 1992, Hurricane Andrew damaged or destroyed more than 125,000 Florida homes and left about 250,000 people homeless. After the category 5 storm, Florida officials conducted a critical examination of state and local residential building codes and enforcement. Andrew had caused about $16 billion in insured damage. What they found were outdated building codes, shoddy construction and flagrant code violations that slipped inspection.
Their findings resulted in a number of reforms to residential building codes and means of code enforcement. Research has demonstrated that the destructive effects from moderate (EF0 to EF2) winds may be avoided by following Florida-style hurricane coastal code. A number of studies conducted since Hurricane Andrew have found that residential construction built to the best available standard can cut hurricane damage by about 50 percent.
Why is this important to us in Oklahoma? Because we have the opportunity to lower the chance of tornado damage by updating our state building codes.
Let me explain.
While an EF5 tornado delivers the greatest catastrophic damage with winds in excess of 200 mph, 95 percent of tornadoes are rated EF2, or 135 mph, and below. Wind speeds rated at EF2 or lower typically cause 85 percent of the damage in an EF5 tornado. In the May 2013 EF5 tornado that hit Moore, wind speeds in excess of 200 mph were less than one percent of the tornado’s footprint.
In the aftermath of that devastating twister, OU Associate Professor of Civil Engineering Dr. Chris Ramseyer led a team of professors, scientists and engineers through the disaster zone to examine what impact the tornado had on homes and other buildings. They discovered that homes recently built to higher-quality construction standards sustained less damage than homes built to a lesser standard.
Ramseyer recommended the City of Moore upgrade its residential code to require building techniques that allow homes to withstand winds up to 135 mph, the equivalent of an EF2 tornado. The old standard only required homes to withstand 90 mph winds. Ramseyer’s recommendations would make homes stronger, but it would only raise the cost of new home construction by one to two percent. The Moore City Council voted unanimously to approve the new building code.
In the Moore tornado, 88 percent of the damage was caused by wind speeds rated EF2 or lower. If the impacted homes had been constructed to Moore’s new building code, it is calculated that approximately 1,012 of the 1,150 damaged homes would have withstood the destructive forces experienced that day.
Since 1989, Oklahoma has experienced almost $32 billion in insured losses due to the 1,575 tornadoes that wreaked havoc on our state. The time has come to learn from the experiences of Florida and the City of Moore. We can start the process to mitigate future tornado losses by embracing the tornado-resistant residential building code as a statewide construction standard. As an added benefit, the same standards that make a home more resilient to tornadoes also improve the home’s performance in an earthquake.
In the coming legislative session, I will advocate the adoption of tornado-resistant fortified home construction standards as our state standard for new home construction. Stronger homes provide us with enhanced security and a chance to save money on insurance premiums. Tougher building codes could also translate into lower insurance claims costs for insurance companies and protect Oklahomans and their possessions after a devastating storm. The benefits may not be evident at first glance, but the peace of mind with stronger homes will last a lifetime.