News Analysis: Hurricanes

Hurricane Aftermath: Hurricanes Florence and Michael Leave Lasting Impact

By Jordan Scott

Hurricane season is often unpredictable, from the number of storms to their intensity at landfall. The 2018 season has brought major damage to the U.S. through Hurricane Florence and Hurricane Michael, which both impacted the East Coast in unexpected ways.

Destructive Storms

Hurricane Michael was at Category 2 storm 24 hours before making landfall in the Florida Panhandle on October 10, 2018. It quickly intensified to a Cate-gory 4 and caused severe damage to the area, which has less stringent wind-resistant requirements for buildings than in areas more prone to hurricanes, such as Miami-Dade. The historic hurricane was the strongest to hit the continental U.S. in more than 25 years.

Several glass companies in the Panhandle closed for evacuations prior to the storm, while others prepared for what they thought might be a weaker storm.

Miller Glass in Tallahassee, Fla., wasn’t located in an evacuation zone, but closed on October 10 in anticipation of Hurricane Michael’s landfall. According to Adam Jones, residential project manager at Miller Glass, the company postponed some of its jobs closer to the coast.

“We have a wide service area that goes down to coastal communities like Apalachicola and St. Marks,” said Jones.

Apalachicola, Fla., is only 35 miles from Mexico Beach, Fla., which was nearly destroyed during the storm.

As people assess the damage and look toward recovery, logistics can be a challenge. Robert Struble, brand and communications manager at Vitro Architectural Glass says, “The issue is typically that trucks become more difficult to obtain because so many are hauling emergency aid.”

Less than a month before Hurricane Michael hit Florida, Hurricane Florence brought major flooding to the Carolinas when it made landfall as a vast Category 1 hurricane on September 14. Though much weaker than its peak Category 4 status off the coast, the hurricane moved over the Carolinas, bringing days of heavy rain. The storm killed nearly 50 and damaged homes and businesses in both North Carolina and South Carolina. Many roads remained flooded weeks after the storm, making clean-up efforts difficult in some of the hardest hit areas, such as Wilmington, N.C. The cost of the damage is estimated to be around $22 million according to Moody’s Analytics.

It’s too soon to say what impact these recent storms will have on the areas hit as far as code changes. However, if past storms such as Andrew in South Florida and Katrina in New Orleans are any indication of what’s to come, we could see some changes in the future. Jeff Rigot, who handles southeastern sales for Viracon, says time will tell what the impact of Hurricane Michael will do to future iterations of the Florida Building Code Chapter 16 Structural Design.

“Most of the Panhandle region, and in particular the Apalachicola Bay area, falls out of mandatory hurricane protection for Risk Category II buildings; and what areas that do are mostly the lesser Wind Zone 1 windborne debris protection criteria listed in ASTM E 1996.”

He continues, “Michael was the most intense wind event on record to hit the Florida Panhandle. With this, combined with today’s comprehensive media coverage of these kinds of events, I expect there will be some serious discussions within that region’s legislative and general public communities to enhance hurricane building code requirements. Ultimately the debate will come down to preventing loss and saving lives versus the economic impact the additional financial costs associated with stronger hurricane code protection places on the building community.”

Engineers from PGT Innovations assessed damage done by Hurricane Michael in Panama, City, Fla., for the Structural Extreme Events Reconnaissance Network. The engineers witnessed damage to both residential and commercial structures.

According to the company, they saw many non-impact window and door failures due to impacts from wind-borne debris and wind pressure that exceeded the strength of the older windows and doors. Buildings that were well engineered and hardened fared better than more vulnerable structures.

“Miami-Dade and Broward counties adopted strict standards, requiring homes to be ‘hardened’ with protective building products so as to make structures able to withstand winds up to 175 mph,” says Dean Ruark, vice president, product management and engineering. “Post-storm assessments of Hurricane Irma made it clear that buildings constructed to new codes had performed extremely well and the damage of such extreme weather was much less than it could’ve been. In some communities on the Florida Panhandle, new construction homes only need to withstand wind speeds of 130 mph or less — far below the 155-mph winds seen during Hurricane Michael. In the aftermath of Hurricane Michael, as local, state and federal officials assess the damage, a consensus is thankfully emerging that building codes along Florida’s Panhandle need to be tougher.”

Lessons from Irma

While the damage from Hurricanes Florence and Michael is still being assessed, experts are now able to report on the extent of damage from Hurricane Irma in Florida last year. The American Architectural Manufacturers Association (AAMA) hosted a webinar titled “Hurricane Irma: Lessons Learned,” in which Chris Matthews, vice president and senior consultant of GCI Consultants, shared how glazing systems performed during the storm based on the observation of hundreds of buildings in the hardest hit regions of Florida.

Hurricane Irma struck Florida from September 9-10, 2017. It first hit the Florida Keys and South Florida before heading toward North.

“What was different about this storm was the wide range of the state it affected. Irma was strong, relatively wide and tracked up the western part of the peninsula,” said Matthews.

Some glazing systems in the Keys and on the Southwest and some Southeast coasts were blown out or had broken glass. Other systems had frame damage, but the majority of damage to glazing systems was by water intrusion.

GCI Consultants looked at the performance of a wide age range of products. Some systems and buildings included newer impact-resistant systems while others included the original systems installed 30-40 years ago.

“As we would anticipate, the new impact-resistant, higher load systems performed better. They performed well structurally, and as for impact resistance, did the job they were designed to do by protecting the enclosure from wind and wind-borne debris,” said Matthews.

He explained that many of the older systems had structural failures related to the original design intent of the systems, age of the systems, how well they were installed and how well the walls around the systems held up after the storm. There was more blown out and broken glass in the older systems.

“Something we saw in both older and more modern systems was water infiltration during the storm,” said Matthews. “We saw more of that than we’ve seen in recent storms we’ve investigated through a large area of the state.”

In non-impact systems, which are generally more than 20 years old, glass was blown out or the envelope was completely breached. They performed poorly in all aspects, according to Mat-thews. He said impact systems also sustained damage, but protected the envelope. They didn’t see blown out panels or glass broken out of the opening in those systems. They saw more discreet damage to the assemblies and frames. Fixed glazing systems per-formed better than operable doors and windows.

One trend that Matthews noted is that some buildings had new glazing systems, but there was no attention given in some cases to the surrounding substrates anchoring in the doors and windows. The glazing system itself would not be damaged but the drywall would be damaged.

Another common theme presented itself in buildings with newer systems.

“They had systems that had never leaked previous to the hurricane. They had leakage during the hurricane, but then, several months later, they’re having water leakage in common thunderstorms that were not occurring prior to the storm,” said Matthews.

Matthews said that when storms occur, very good systems can still have water infiltration if the storm exceeds resistance ratings.

To view the laid-in version of this article in our digital edition, CLICK HERE.

 

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