Blast Testing
In general terms, glass will break when subjected to pressures in excess of 1lb per square inch (psi) (6.89 kilopascals). Whilst most testing of window film has been undertaken to provide data specifically for protection against terrorist explosions, the essence of what was learnt can be applied to industrial blasts. The most comprehensive testing of this kind was commissioned by 3M in the US and was carried out in 2003. The objective of these tests was to compare the effect of an explosion on various glazing configurations and, in particular, the travel of glass fragments. Ordinary annealed glass, double glazing and toughened glass, without film treatment, would all achieve the lowest rating of five and would constitute a major threat to life.
Figure 3: 3M Tear Test showing how 3M Scotchshield(tm)
Ultra High Performance window film performs compared to standard films.
Even controlled pressure applied to film with tear
Selected Test Results
These results illustrate the effectiveness of the Ultraflex frame anchorage system on double-glazed units. A similar polarisation of the results would be expected when comparing the effect of the same explosion/distance on single glazing with toughened glass.
Figure 4: Glass shattered as a result of an explosion is held together
by window film reducing the threat to those inside the building.
These illustrations show the calculated damage
to a building based on the Sept 2003 tests undertaken for 3M.
Duty of Care
The one thing you can be sure of with explosions is that they are as unpredictable as they are unwanted and therefore it is essential that basic measures of protection are put in place. Window film is a tried and tested basic measure of protection that upgrades glass to meet safety standards in buildings. It is beholden on those in high-risk industries such as oil and gas to ensure they make adequate provision beyond what basic standards demand for the safety of people.
Figure 5
a) Situation 1 – no window film. This shows how toughened glass offers very little resistance to a blast
b) Situation 2 – With Ultraflex. The same blast but the glass is contained by the window film and frame
Category:
Health & Safety
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