As the end of the 2018 hurricane season nears, the American Architectural Manufacturers Association (AAMA) is reflecting on one of last year’s most destructive storms: Hurricane Irma. In a webinar titled “Hurricane Irma: Lessons Learned,” 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 Matthews. 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 performed 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. “The systems performed as they were designed to perform, but there’s some discreet type of damages that are allowing continued leakage after the storm. We’re investigating that. We’ve looked at 400-500 buildings and are doing field water infiltration testing to see at what level these systems are performing now.”
The cause of water infiltration in newer systems could be a preexisting condition exacerbated by the storm, that the storm exceeded the window rating or that the windows were damaged by the storm.
GCI Consultants has several recommendations based on its observations:
- Replace non-impact glazing systems with new impact-resistant and structurally superior systems;
- Analyze and reinforce window openings as necessary;
- Waterproof openings before installing new systems;
- Asses the water infiltration resistance ratings of new systems and consider exceeding codes’ minimum requirements; and
- Inspect existing systems annually before June 1 and replace/repair damaged or worn weather-stripping, sealants and hardware.
Matthews said that when storms occur, very good systems can still have water infiltration if the storm exceeds resistance ratings.