Impact Test Result
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Missile Speed 50 fps
Missile Weight 9 lbs
Glass Type Impact
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Broward County Contractors

When Things Fly

A 2x4 board at 50 feet per second. That's what your windows have to stop. Select a glass type and launch the missile to see what survives.

Find Impact Requirements Compare Tests
Impact Test Simulator
Speed: 50 fps (34 mph)
2x4 50 fps
PASS
Impact Glass
Laminated, HVHZ rated
Tempered
Safety glass, not impact
Standard
Regular annealed glass

Large vs Small Missile

Two different tests for two different threat levels

🪵
Large Missile
9 lb 2x4 lumber
50 feet per second
Impact energy: ~350 ft-lbs
Required In
HVHZ (East Broward)
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Small Missile
10 steel balls @ 2g each
80 feet per second
Impact energy: ~0.3 ft-lbs each
Required In
Non-HVHZ (West Broward)

The Complete Test Sequence

Impact is just the beginning - products must survive everything after

1
Impact
2x4 hits at specific points on the glass
2
Pressure Cycle
4,500 cycles of positive/negative pressure
3
Air Test
Check for air leakage at design pressure
4
Water Test
Zero leakage allowed at 15% of DP

Common Questions

What contractors ask about impact testing

What is large missile impact testing?
Large missile impact testing simulates a 9-pound 2x4 lumber board flying at 50 feet per second (34 mph) hitting your window or door. This represents debris that could be launched in a Category 4-5 hurricane. Products must survive the impact AND continue to resist wind and water afterward - not just avoid shattering.
What is the difference between large and small missile testing?
Large missile testing uses a 9 lb 2x4 at 50 fps - simulating major debris. Small missile testing uses 10 steel balls (2 grams each) at 80 fps - simulating roof gravel and small debris. Broward County HVHZ (east of I-95) requires large missile testing. Non-HVHZ Broward can use small missile tested products.
Why do impact windows cost more than regular windows?
Impact windows use laminated glass (two layers bonded with a plastic interlayer) instead of single-pane glass. Even if the glass cracks on impact, it stays in the frame. The frames are reinforced to handle both impact forces and ongoing wind pressure. This specialized construction costs 2-3x more than standard windows.
Can shutters provide large missile protection?
Yes. Properly rated hurricane shutters (accordion, roll-down, or panels) can achieve large missile impact ratings. The shutter must have a Miami-Dade NOA or Florida Product Approval showing large missile testing. The key is matching the shutter's tested configuration to your actual installation.
What happens after an impact test?
After impact, the product is immediately tested for air and water infiltration at its rated design pressure. A window might survive the 2x4 hit but fail if it leaks air or water afterward. The complete test sequence is: impact, pressure cycling (4500 cycles), then final water test. All must pass.

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