Test Program for Enhancing Blast Capacity of Windows

Personnel injury from flying glass produced during an explosion accident can represent a significant hazard, often in excess of hazards due to airblast, primary fragments, building collapse, and secondary fragments. The permissible overpressure in Inhabited Building Distance (IBD) from a Potential Explosion Site (PES) is 1.2 psi. This pressure is sufficient to cause failure of most windows in conventional construction. Failure of these windows can produce hazardous glass shards which can cause serious injury. A research program was initiated to address this issue and develop cost effective methods for mitigating the hazards. The program was designed to address blast loads with a peak pressure up to 7 psi. Anchored widow film systems were designed and tested for low pressure applications. These methods showed a significant increase in blast capacity and reduction in glass fragment hazard. A catch system was developed to arrest the flight of unanchored, filmed panes for blast loads at the upper end of the design range. An analytical method was developed for these capacity enhancement systems. Over 60 validation tests were performed to verify the analytical methods. These tests included evaluation of polyester films, tear resistant films, and laminated glass. Tests were performed in a shock tube capable of producing long duration blast loads with accurate control over peak pressure.