On average, a hurricane season brings 12 named storms, six hurricanes and three major hurricanes annually. A hurricane is classified as major when sustained wind speeds reach at least 111 miles per hour, and the storm is designated as a Category 3, 4, or 5. These are the hurricanes typically remembered for generations, storms like Sandy, Andrew, and Katrina.
However, it doesn’t take a major storm to cause major damage. Strong winds can be one of the most damaging parts of tropical storms and hurricanes. They can decimate structures – risking the lives of building occupants and destroying critical business inventory inside a facility.
When we talk about hurricanes, we cannot talk about a single season. We must look at the risk these strong storms present over time, and a facility’s ability to withstand that risk. There are 185 coastline counties in the United States. When building in or near these counties, special considerations must be accounted for, including wind uplift. The Butler MR-24® roof system is designed to perform under extreme weather conditions such as hurricanes. It can be designed to withstand wind speeds in excess of 180 mph, and it meets the strict requirements of Miami-Dade County.
Real Buildings, Real Results
The Butler MR-24 roof, which covers more than three billion square feet of new and existing structures around the world, was chosen as the roof for the Hurricane Test Laboratories, Inc. facility in Riviera Beach, FL. The engineers and operators at the Hurricane Testing Lab are known worldwide for inflicting severe damage on building components. During testing, they create hurricane-like conditions to see which building parts hold up, and which ones don’t by using cannons, wind machines, and some rather destructive behavior.
When it came time to build a new test center, a Butler building system met the strict South Florida building requirements, as well as the demands of the engineers and operators. The new facility was designed, engineered, and constructed with the Widespan™ structural system and the MR-24 standing seam roof system.
Having been around for more than 50 years, the MR-24 roof system acts like a monolithic steel surface covering the entire building. The interdependence of structural elements sets the roof system apart. It features factory-punched structural members and roof panels to assure precision alignment. And the system’s ability to expand and contract with temperature changes also contributes to its unmatched durability.
When the New Orleans Saints built their new training facility, the team chose the Widespan structural system and the MR-24 roof system for their facility. The building and roof systems withstood Hurricane Katrina in 2005, and the facility served as headquarters for rescue personnel.
“This Butler building saved a lot of lives,” said Terry Ashburn, facility manager of the New Orleans Saints.
And when Hurricane Floyd inflicted significant damage to the Bahamian Islands, the RND Cinemas building escaped damage and was used as an evacuation center.
“I was able to take away with me the fact that our building and the Butler roof had absolutely no damage or leakage whatsoever,” said Jerome K. Fitzgerald, vice president of RND Cinemas Limited.
Engineered for Excellence
The MR-24 roof system features proprietary innovations and design details that set it apart.
- Wider tabs provide a more secure hold. In areas susceptible to extreme weather, the MR-24 roof system is constructed with wider tabs on the roof clip—a full 1-inch as opposed to a standard 5/8- inch. This wider tab is proven to maintain roof integrity under high-wind conditions.
- Optional double clips can be specified to further reinforce the MR-24 roof system. The two-panel clips are attached to a clip spacer bracket using a Butler superior-strength Scrubolt™ fastener.
- Pittsburgh double-lock seams create a true monolithic weathertight surface. Only the MR-24 roof system forms a 360-degree Pittsburgh double-lock seam to create a stronger, weathertight roof system. Other manufacturers snap or crimp panels with a machine, producing a loose, vulnerable seam.
Proven Performance
The MR-24 roof system has been extensively tested both in-house and independently, and it is certified to meet the strictest hurricane codes.
- The Butler Research Center is the industry’s only full-time metal building research and product testing facility in the U.S. Here, the MR-24 roof system is continually pushed to the limits to validate and enhance its superior performance.
- At the Hurricane Testing Lab — an architectural testing services company in Riviera Beach, Florida—the MR-24 roof system passes punishing cyclic wind-load tests, as well as the penetration test of repeatedly firing a 9-pound, 2’x4’ woodblock from a cannon at 50-feet per second.
- The MR-24 roof system is fully tested and approved by the Factory Mutual Research Corporation as a Class 1 panel roof. It is available with wind rating 1-60 through 1-165.
- The MR-24 roof system meets the stringent requirements of the Department of Energy and Florida Building Code 2004, including the High-Velocity Hurricane Zones (HVHZ) requirements of Miami-Dade and Broward Counties.
- The MR-24 roof system has been tested and certified in accordance with the Army Corps of Engineers Guide Specification 07416 (Test Method for Structural Performance of Standing Seam Metal Roof Systems By Uniform Static Air Pressure Difference).
- The MR-24 roof system carries the highest wind uplift ratings awarded by Underwriters Laboratories.
When wind uplift is a concern, closer purlin spacing can be incorporated into the building’s design. This provides additional structural support. Additionally, in high-wind regions, the purlins of a Butler building system are spaced at end bays to provide added structural support necessary for extreme weather conditions.
While both the Hurricane Testing Lab and the New Orleans Saints chose Widespan structural systems for their facilities, the MR-24 roof system can easily integrate with hard wall materials such as tilt-up, precast, and masonry walls. Our engineers review a variety of structural approaches to primary and secondary framing, as well as bracing design, to assure superior building strength and integrity. This capability provides building owners with expanded design freedom and enhanced protection.
Sources
Insurance Information Institute: https://www.iii.org/fact-statistic/facts-statistics-hurricanes
University of Illinois: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hurr/damg/wind.rxml
United States Census Bureau: https://www.census.gov/newsroom/facts-for-features/2017/cb17-ff13-hurricane.html