The glass in your hurricane window sits inside a channel called the "pocket." If that pocket is too shallow, wind pressure can pop the glass right out - even if the glass never breaks. Here's how deep it needs to be.
The depth isn't just a number on a spec sheet. It's the difference between glass that stays put and glass that becomes a projectile.
A deeper pocket means more glass surface contacts the gasket and sealant. This spreads wind load over more area and prevents the glass from being levered out.
When wind hits the glass, it bows inward or outward. This puts tremendous stress on the edges. Deep pockets let the glass flex while still holding the perimeter secure.
Glass expands and contracts with temperature. A deeper pocket with proper spacers allows this movement without compromising the seal or stressing the glass edge.
Glass size varies slightly from the order. Deeper pockets accommodate this variation so the glass doesn't end up with one edge barely engaged in the channel.
Larger glass panels need deeper pockets. Here are typical minimums for HVHZ areas.
See how different pocket depths affect glass security.
Minimal glass engagement. Can pop out at 60 mph. Does not meet any code for HVHZ.
Standard non-HVHZ depth. May meet code for low wind zones. Not adequate for Broward.
Deep engagement on all sides. Meets HVHZ code. Tested for 150+ mph winds.
Enter your glass dimensions to see recommended pocket depth.
Glazing pocket depth is how far the glass sits inside the window frame. Also called "glass bite," it's the distance from the edge of the glass to where the frame pocket ends. Deeper pockets hold glass more securely during wind pressure.
For HVHZ areas like Broward County, typical minimum glazing pocket depth is 3/4 inch (19mm) on all sides. However, larger glass units and higher wind zones may require 1 inch or more. The exact requirement depends on glass size, type, and design pressure.
During a hurricane, wind pressure tries to push or pull the glass out of the frame. If the pocket is too shallow, the glass can pop out even if it doesn't break. Deeper pockets provide more surface area for the gaskets and sealant to grip the glass.
Shallow pocket depth can cause glass to pop out of the frame during high winds, even if the glass itself survives impact. Once the glass is out, the building envelope is compromised and wind/water can cause massive interior damage.
You typically can't measure pocket depth without removing the glazing stops. A window professional can inspect your windows. On most hurricane windows, the spec sheet lists the pocket depth. If your windows are pre-2002 in Broward County, they likely don't meet current depth requirements.
Get engineer-stamped calculations that specify exact glazing requirements for your Broward County project.
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