| One of the main concerns of architecture in | | | | protection as they are thicker than regular glass. |
| recent times is to protect the buildings from | | | | Laminated glasses are made by introducing a |
| terrorist activities. Even the glass manufacturers | | | | layer of PVB or Polyvinyl Butyral between two |
| are working very hard to manufacture glasses | | | | layers of glass. The PVB has a minimum thickness |
| that will resist the heat and the impact of bullets | | | | of 1.5 mm while laminated glasses have a |
| and bomb blasts. | | | | minimum thickness of 7.5 mm. resistant glazing |
| These are commonly known as blast resistant | | | | does not break; instead they bend under the |
| glass. When a blast occurs, one of the chief things | | | | impact. |
| that harm people around is shards of broken | | | | Precautions: |
| glass. During a blast, the glasses in close proximity | | | | However, the blast resistant should not be too |
| break and fly in the air in the form of sharp tiny | | | | rigid. This has an adverse effect during the blast. |
| pieces. Thousands of tiny shards of glass flying in | | | | If the resistant glazing is too rigid it tends to |
| the air prove to be very dangerous. These shards | | | | transfer the entire energy of the blast to the |
| have the ability of flying to a distance due to the | | | | frame and the structure of the building. The |
| pressure wave in the air created by the explosive | | | | building gets affected badly as the forces of the |
| device.resistant glazing has the ability of absorbing | | | | blast penetrate the building. |
| a lot of the energy created by the blast. The | | | | Not all kinds of laminated glass act as good blast |
| blast resistant glass can also deflect the energy. | | | | resistant glass. Several factors are responsible for |
| The manufacturers of glass have studied the | | | | making a glass resistant to blasts and bullets. The |
| effects of a blast in a building and have come up | | | | physical properties of the PVB, the thickness of |
| with the concept of resistant glazing. | | | | the glass, the finishing and the frame contribute in |
| The blast resistant glass is made in a way that it | | | | making the glass resist the impact of a blast. The |
| does not break away from the frame and fly | | | | kind of frame used with blast resistant glass is |
| around in the form of glass debris. When a blast is | | | | also important. The frame should be able to |
| unable to break the glass, the integrity of the | | | | withstand the bending of the blast. It should be |
| building is not lost. | | | | able to withstand 7kN static load per square |
| How is blast resistant glass made? | | | | meter. The fixings should be able to withstand |
| Laminated glasses offer a higher degree of | | | | 20kN per meter of perimeter. |