The National Archives and Records Administration (National Archives) has unveiled page two of the US Constitution secured in its new, high-tech encasement, which includes a large window made of lamina…
The National Archives and Records Administration (National Archives) has unveiled page two of the US Constitution secured in its new, high-tech encasement, which includes a large window made of laminated glass with Solutia“s Saflex. Each encasement produced for the National Archives will contain the same glass – which has the Saflex plastic interlayer laminated between two plies of glass – to protect the document from a variety of potential hazards, and to provide visitors with a clear view of each document. Laminated glass, which is used in residential and commercial buildings, as well as automobile front and side windows, will provide the “last line of defense” for the documents, dramatically decreasing the risk of glass particles damaging the documents in the unlikely event of a catastrophe. The laminated glass used by the National Archives is composed of a tough polyvinyl butyral (PVB) interlayer material donated by Solutia Inc., bonded with heat and pressure by Viracon Inc., between two plies of Pilkington Optiwhite(TM) low iron glass. Upon impact, the glass itself may crack, but the fragments tend to adhere to the Saflex plastic interlayer and remain in its frame. By keeping the glass in its place, laminated glass made with Saflex provides protection from dangerous flying or falling glass fragments. Within the building industry, laminated glass is used in windows and doors for added safety and security. It is used around the world to prevent and deter theft from break-ins, and to mitigate the damage associated with hurricanes, earthquakes and bomb blasts, which generally cause ordinary glass to break into large shards, and present a grave danger when the shards fly or fall. In the automotive industry, laminated glass in windshields has protected vehicle occupants for more than 60 years. Recently, some auto manufacturers have added Enhanced Protective Glass (EPG), a new category of laminated glass specifically designed for the side and rear windows of vehicles. EPG offers a variety of benefits, including intrusion resistance, protection of occupants during an accident, UV and heat reduction, and the reduced transmission into the vehicle of airborne road noise.