Bomb Blast Window Film from Sureguard Window Films

There are many different kinds of incendiary devices of varying explosive force. However the principles of all bombs are based around the quick, successive movement of air in cycles of positive and negative pressure waves.

These waves create rapid changes in the pressures exerted on the fabric of a building, causing opposing forces on either side of the materials.

The leading phase of an explosion is of negative pressure, sucking all the air towards the explosion source. The air pressure within the building is also pulled towards the oncoming wave, exerting force on the external structure causing outward bowing into the negative cycle, in turn weakening the structure.Within milliseconds the positive phase strikes the building.

The negative phase will now have entered the structure and the force will push the building material inwards. This action will continue through the overall cyclic duration of the blast and will have differing effects on the building materials used to construct the building.

Unlike many building materials glass is not very flexible and once its stress points are exceeded it will break. The nature of the breakage will depend on the glass type, its size and to some extent the framing material.

The first, negative phase of an explosion will apply forces to the glass that will make the glass bow into the oncoming force. Depending on the pressure of the leading edge, this bowing could be sufficient to break the glass. The positive phase, immediately following, would push the broken pane of glass into the building.