bulletproof windows FB4 with ER2 glazing
Bulletproof windows and fixed partitions in class FB4 with glazing in class ER2 are innovative aluminum constructions ensuring high ballistic resistance and resistance of glazings to shockwaves generated by detonation of explosive charges. A characteristic feature of constructions of this type is their reinforced designed and the application of glazings with enhanced resistance against breaking and penetration by bullets discharged from firearms. In practice, such glazings offer excellent protection against bullets, detonations of explosive charges and against manual attack or break-in with the use of sharp tools.
The design of FB4 bulletproof windows with ER2 glazing
is the effect of many years of experience in raising the security of aluminum-glass constructions against break-in, manual attack or firearm discharge. A basic practice in the designing of bulletproof windows and partitions is to apply steel-aluminum frames capable of absorbing kinetic energy and preventing perforation and exit of projectiles into the interior side. Another important element of bulletproof windows and partitions is the glass used in glazings. In the case of FB4 windows with ER2 glass, the glazing is of class BR4 according to standard PN-EN 1063 and of class ER2 according to standard PN-EN 13541. Such glazing is resistant to discharge from high-caliber small arms as well as to detonation of an explosive charge with moderate overpressure of the reflected shockwave and its impulse. Glass compliant with standard PN-EN 13541 is classified into four classes from ER1 to ER4, where class ER1 is the lowest and ER4 the highest. The measure of resistance to detonation and the basis for classification from ER1 to ER4 is the overpressure of the reflected shockwave and the duration of the positive overpressure phase following detonation.
In the case of FB4 bulletproof windows with ER2 glazing, fittings ensuring resistance to bullet penetration of opening and tilting window casements are another important element. Fittings have additional locking latches, mounted so that projectiles discharged from firearms will not break the window casement out of its frame or open it. An FB4 window provides effective protection against firearm discharge only in the closed and locked position, which is why fittings are specially protected against projectile impacts that could destroy locking mechanisms and cause the casement to open or tilt inwards.
Tests of FB4 bulletproof windows and partitions with ER2 glazing
were performed using the methods provided for in standard PN-EN 1523:2000 and confirm their exceptional security-related properties. The testing procedure calls for performing multiple attempts to penetrate the construction with two types of firearms of differing calibers, from a distance of five meters. The firearms used in the procedure of testing FB4 bulletproof windows with ER2 glazing were a 11.2 mm caliber 44 REM MAG revolver and a 9 mm caliber Magnum 357 revolver. Both types of revolvers, with ammunition, respectively, the 44 Magnum with flat lead bullets weighing 15.6 g and the 357 Magnum with cone-point lead bullets weighing 10.2 g, are used in accordance with testing standard PN-EN 1523:2000 for testing of constructions meant to achieve class FB4 bullet penetration resistance according to classification standard PN-EN 1522:2000. During ballistic tests, all elements of the construction of bulletproof windows and partitions were tested: glass glazings, all joints between frame and casement profiles, contact points between profiles and glazings, casement edges and fittings, with particular emphasis on hinges and the locking mechanism. The number of shots fired, choice of targeting points and firing angles rigorously implement the methods given in the testing standard, and through this, confirm the excellent properties of bulletproof aluminum window and partition constructions. The bullet penetration resistance of FB4 windows with ER2 glazing is additionally classified as NS in terms of the appearance of fragments on the interior side following firearm discharge.
The applications of bulletproof windows and fixed partitions in class FB4 with ER2 glazing
are very broad and concern the separation of buildings or specific rooms requiring special protection against attack from generally accessible areas. Bulletproof windows and partitions of this type are installed in separations meant to withstand discharge of small arms of various calibers, shockwaves generated by detonation of explosives, as well as manual attack with the use of heavy tools. The appliication of class ER2 glazing according to standard PN-EN 13541 allows for the achievement of special functional properties. Multi-layered protective glass, assembled into a sandwich construction consisting of layers of bending-resistant tempered class separated by layers of rupture- and penetration-resistant laminate, provides the end result of the resistance to detonation shockwaves and firearm discharge for which the FB4 class is defined, while simultaneously meeting fragment penetration requirements. The NS class, signifying the lack of fragments on the interior side, reduces the probability of injury due to fragments and is a particularly desirable property in public buildings.
Class FB4 bulletproof windows and fixed partitions with class ER2 glazing find applications in, above all, military facilities, but are also widely used in other places at risk of firearm discharge or terrorist attacks with the use of explosive charges. They are installed in government buildings, courts, diplomatic facilities, banks, museums and art galleries. Bulletproof windows and partitions of this type are tested for thermal insulation and can be used for both exterior and interior applications.
