 | Bob Crager of Lewis Street Glass is a 26 year veteran in the glass business. Lewis Street Glass is a leading Wichita Glass company, serving the entire Wichita/Sedgwick County area since 1919. They do anything and everything having to do with glass, both residential and commercial. They also do Auto glass. They are located at 743 South Market, facing Kellogg on the South, and you can reach them by phone at (316) 263-8259. You can email Bob Crager at bcrager@lewisstreetglass.com |
Glass
2006-08-01 09:43:00
The danger of storm-broken windows
ANSWER: Conventional window glass used in homes and business applications normally was not designed to resist wind-blown debris, such as tornados, hurricanes, earthquakes, explosions and/or terrorist attacks. When subjected to these kinds of stresses, existing glass often breaks into lethal shards that are hurled from the window frame, thereby endangering building occupants and passers-by. Broken glass also causes additional property damage.Security window film can improve the ability of existing glass to mitigate the impact of explosive forces and wind-blown debris. The primary function of security film is to hold glass intact if it is indeed broken. A hurricane or tornado can hurl an object through a window, thus causing dagger-style glass shards to strike the occupants. A bomb exploding creates a shock wave that breaks glass into lethal projectiles. A sufficient explosion may cause glass to become atomized. When an explosive shock wave causes victims to gasp for air, they breathe in the atomized glass particles and often die from that. Typical window performance problems include unacceptable air infiltration, poor insulating capability, the inability to block solar heat, transmission of ultraviolet radiation and noise, and vulnerability to electronic eavesdropping. Security enhancements to glass become more economically feasible if they also improve window performance capabilities.Existing glass can be replaced with laminated glass, which is actually two or more pieces of glass, bonded by a polyvinyl butyral plastic interlayer. Compared to conventional glass, laminated glass can provide much increased resistance to wind-blown debris and seismic and/or explosive forces. Security window film is an alternative to replacing existing glass with laminated glass. Window film can be optically clear, tinted or reflective, and it is applied to the interior surface of existing glass. Typical film installations cover the visible portion of the glass surface to the edge of the frame, but do not extend to the glass edge inside the frame. Film can be applied to either single pane or many types of insulating glass. When the appropriate film is properly applied to insulating glass, it does not impact the integrity of an insulating glass sealant or generate thermal stress to glass from uneven heat absorption. Applied security window film is available with or without solar control capabilities. Because security window film can stretch without tearing, it can absorb a significant degree of the shock wave of an explosion. As this explosive force moves toward the glass and pushes it inward, the glass eventually cracks and breaks. However, the security film applied to the rear of the glass continues to absorb the shock wave, stretching until it can no longer bear the pressure, at which time it bursts. The shock wave, when great enough to break the glass, is not enough to shear the film. This results in the glass being broken but held intact by the film. Both laminated glass and security window film can mitigate the impact of explosions, wind-blown debris and earthquakes. The performance of both depends on the relationship of each to the existing window frames. More next month…
