Anti-shatter Window Film
Anti-shatter window film offers a convenient way to make glazing safer and should form the basic minimum measure taken by higher risk industries like oil and gas. The application of film is convenient because it can be applied on site with little disruption to work in progress and the cost is far less than replacing the glazing. Anti-shatter film is applied to the inside of glazing by professionally trained installers as the quality of installation will make a significant contribution to how well the product works and how long it will remain effective. Modern high-tech window films work because they are extremely resistant to tearing.
Global company 3M’s Scotchshield™ Ultra High Performance window film has tested as 44 times more resilient to tearing than other standard film on the market. Ultra High Performance film gets its strength from the 39 separate layers of polyester and high performance adhesive.
Table 1
Tests undertaken by Applied Research Associates for
3M in September 2003. 600 lb of Ammonium Nitrate and Fuel Oil
(equivalent to 550 lb of TNT) was detonated at a stand-off distance of 170 feet.
Anti-shatter window film adheres to the glass and in the event of an explosion holds the shattered glass intact whilst absorbing and containing huge surges of energy. A filmed window will typically bow under the pressure of an explosion, but generally will be held intact even if the whole window pane subsequently drops away. The key to reducing danger to life and restricting collateral damage is to reduce the distance and speed that the glass travels. Window film dramatically reduces the number of glass projectiles and seriously reduces the distance that any shattered glass travels.
Figure 1a: Damage comparison calculations.
this shows the calculation for a building without window
film and the windows shaded red (all windows) will fail catastrophically.
Figure 1b: This shows the calculation for a building with window film
and the orange shaded area shows where the filmed glazing will fail and
could be hazardous. The green shaded area shows where the filmed glazing
might crack and where fragments will enter the room to a distance of 10 feet – but generally this will represent a low risk.
Frame Anchorage
In order to meet ever greater threats from terrorist organisations, 3M and Dow Corning have developed a frame anchorage system that provides even greater protection. Called Ultraflex, this system takes the inherent strength of 3M Scotchshield™ Ultra High Performance and combines it with Dow Corning 995 structural silicone to create a situation where glass, film and frame are bonded into one single strong unit. The structural silicone has the capacity to stretch more than five times its original set mass. In comparison with glass which is an inflexible material that easily breaks and shatters into many pieces, Ultraflex transforms the window by increasing its elasticity making it much more capable of staying in one piece and remaining adhered to the frame.
Figure 2: The nature of explosions
Force. A typical gas explosion of lower force but longer duration.
Duration. A detonated explosive would usually generate great force dissipated over a short period.
Category:
Health & Safety
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