How Are Doors Tested for Impact Resistance?
Impact resistant doors go through various tests to assess their robustness, including missile debris tests.
The large-missile debris test: This test requires the door to withstand the impact of being hit by a 9-pound 2x4 piece of lumber traveling at 34mph. The door must pass both negative and positive wind load for at least 9,000 cycles. For the door to pass this test, it should not develop a hole that is larger than "1/16x5"mm in the interlayer section of the glass.
Small-missile debris test: This test requires the door to withstand hits by 10 ball bearings moving at a speed of 50mph. The door is then tested for impact by wind loads traveling at 9,000 cycles.
Doors that have passed the hurricane impact tests are regarded as impact rated products. Buyers ought to understand that there is a huge difference between HVHZ-rated products and those that have not achieved this rating. HVHZ rating means that the missile does not penetrate the door and the protective system. Doors with this rating do not allow the missile to break the glass behind the protective layer.
Impact resistant doors that have non- HVHZ rating allow the missile to penetrate the protective system. However, the crack or hole does not increase with each hit and should have a diameter of less than 3 inches when the test is completed.