There is an increasing desire to create buildings and entrances with as much ‘open space’ and natural light as possible.
The use of glass to deliver the feeling of light and openness as a building material of choice has increased.
The threat from external deliberate and forceful attacks on buildings and their occupants has long been a problem and is in no way diminishing. The use of glass can become problematic when we then try to incorporate security and in particular ballistic and blast protection.
Ballistic glass, sometimes also referred to as ‘bullet glass’, is constructed of several layers of glass, PVB and sometimes with the addition of specialist polycarbonates.
These layers gradually erode the penetration of the bullet when it strikes the glass.
Bullet glass can be very thick, and so any tint inherent in the glass can be multiplied many times and cause diminished light transfer, and green colour is visible. The use of low-iron glass should improve clarity, ensuring that maximum light passes through the panes.
Blast-resistant glass characteristics are a combination of the rigidity and compressive strength of glass with the plasticity and energy-absorbing properties of polymer interlayers. The glass should remain in its frame to prevent glass shards from becoming a secondary weapon.
Blast resistant products are classified with codes such as ER1 to ER4. These codes relate to the size of the shock wave generated by varying sizes of TNT high explosives placed in varying distances from the glass.
The effectiveness of a blast solution that incorporates glass will depend on far more than just the glass. How the glass is framed, and in what type of wall it is fixed, will substantially affect the effectiveness of the barrier.