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Insulated Metal Panel Buildings Can Meet the Codes for Hurricane Zones

To weather watchers there seems to be two seasons in Florida: Hurricane Season and Preparing for Hurricane Season.

Florida Division of Emergency Management recently tweeted: “Hurricane season doesn’t begin until June 1 but @NHC_Atlantic is already tracking the first tropical wave of 2022.”

Florida can be forgiven for having hurricanes on the brain as this state has seen its share of destruction from Mother Nature, especially from Hurricane Andrew in 1992 which caused over $25 billion in damage and 65 people lost their lives.

Craig Fugate, who has led the Federal Emergency Management Agency and the Florida Division of Emergency Management, told Scientific American last year that “Florida developed the nation’s strongest statewide building code after Hurricane Andrew in 1992 destroyed tens of billions of dollars’ worth of property and exposed weak construction practices that left many homes unable to withstand the Category 5 storm.”

Many builders have found in recent years that insulated metal panel buildings can meet the strong codes required for these hurricane zones.

Metal: A Shelter from the Storm

The Metal Roofing Alliance (MRA) says that metal, when properly manufactured and installed, can be a shelter from the storm.

“A metal roof can withstand decades of abuse from extreme weather like high winds, heavy snow, hailstorms and even wildfires. Metal roofing has a 140-mph wind rating, meaning it can withstand wind gusts up to 140 miles per hour,” says the Metal Roofing Alliance.

Architect Rich Carrol said that under high wind conditions, “metal roofing systems have wind resistance and uplift resistance that is above the new building code requirement. That gives us a sense of relief in that we can use the best material to meet those criteria."

Metal roofing that can withstand hail, driving rain and extreme winds including F-2 tornado force winds of up to 140 mph can be the difference maker when disaster strikes.

“It’s not uncommon to see images of neighborhoods that show mass destruction after a hurricane, and yet the homes that have been properly fortified are still standing,” said Renee Ramey, Executive Director of the MRA. “We hear stories from homeowners all the time who credit their metal roof for literally saving their home during a monster storm. It all starts with making the right decisions and choosing more resilient materials and installation processes right from the get-go.”

Florida Hurricane Zone Building Codes are Stringent

Florida’s building code, put into effect in 2002, is famously stringent when it comes to windstorm resistance for homes built along the hurricane-prone Atlantic shoreline, says The New York Times.

Again, the stronger building codes in Florida can be traced back to Hurricane Andrew which was one of the costliest natural disasters in U.S. history and damaged or destroyed more than 125,000 homes and 80,000 businesses.

The problem is shared across all U.S. coastlines threatened by tropical storms.

“Last year was a hazardous one for homeowners … producing the most active Atlantic hurricane season on record,” said the Insurance Institute for Business & Home Safety (IBHS) last year. “Driven by warmer temperatures, hurricane season alone inflicted at least $60 billion in damages and threatened every mile of the Atlantic coast from Texas to Maine.”

Florida scored the highest in the 2021 edition of Rating the States, which evaluates the 18 states along the Atlantic and Gulf coasts based on building code adoptions, enforcement, and contractor licensing.

“Building science has advanced significantly over the last decade, providing cost-effective strategies to reduce the impact of Mother Nature. Modern building codes are core to addressing the known risks of high winds and heavy rain that invariably come with these systems,” said Dr. Anne Cope, chief engineer at IBHS.

Drawing upon the national model building codes and national consensus standards of the International Code Council, the Florida Building Code is updated every three years and may be amended annually to incorporate interpretations and clarifications.

Florida’s Designated High-Velocity Hurricane Zones

Florida also responded by designating high velocity hurricane zones (HVHZ) which include all Miami-Dade County and Broward County

“Essentially, building products specified in these counties must be tested to HVHZ's high standards of performance, the two main requirements being laboratory-tested resistance for structural wind loads and an ISO-based production quality assurance program, audited by an approved third party,” says Building Design + Construction.

Buildings and structures in the high velocity hurricane zones must be designed and constructed to meet the requirements of Chapters 26 through 31 of ASCE 7, the American Society of Civil Engineers standard for minimum design loads for buildings and other structures.

Passing the Tests to Become Hurricane Rated

Structure Magazine says that ASCE 7 test procedures were once unique but are now standardized as ASTM E1886 and ASTM E1996 and codified in the International Building Code (IBC).

The tests are described as:

  • In the large missile test, a 9-pound, 2×4 stud (approximately 8 feet long) is fired at the window, shutter, or wall system at a speed of 34 miles per hour.
  • For the small missile testing, ten 5⁄16-inch-diameter steel balls (initially small gravel was specified) are shot at the test specimen at 50 miles per hour.

“In both the small and large missile tests, the test specimen must resist cyclic forces similar to hurricane winds for over 3 hours, and this occurs after two or more impacts to the specimen,” writes Structure Magazine. “Furthermore, the test must be repeated on three samples. While the glass may crack during testing, there can be no cracks more than 1⁄16-inch wide and 5 inches long through which air can pass.”

Green Span Profiles insulated metal panel wall and roof system, for example is approved for installation in the HVHZ after undergoing a series of tests including:

  • Large Missile Impact Test
  • Uniform Static Air Pressure Test
  • Susceptibility to Leakage Test
  • 2000-hour and 1000-hour Salt Spray Test
  • 2000-hour Accelerated Weathering Test

Topics: Product Testing, Insulated Metal Panels, Safety