1.1 This International Standard determines resistance of security glazing products to natural threats characterized by simulated destructive-windstorm events. Classification is intended as basis for judging the ability of glazing to remain without openings during a severe tropical cyclone with sustained wind speed of 50 m/s or greater. Impact by missile(s) and subsequent cyclic static-pressure differentials simulate conditions representative of windborne debris and pressures in a destructive windstorm. Glazing is tested in a standard frame. Classification is selected for a geographical location using the appropriate wind speed, pressure and level of protection. 1.2 The test method determines the performance of security glazing for use in fenestration assemblies under conditions representative of events that occur in severe, destructive-windstorm environments using simulated missile impact(s) followed by the application of cyclic static-pressure differentials. 1.3 A missile-propulsion device, an air pressure system and a test chamber are used to model some conditions that can be representative of windborne debris and pressures in a windstorm environment. 1.4 The performance determined by this test method relates to the ability of glazing in the building envelope to remain without openings during a windstorm.