Tower windows to learn safety film....

Tower windows to learn safety film. The 4,900 windows of the CNA Plaza in downtown Chicago are being reinforced with a polyester film following the failure of a 29th floor window in October, resulting in falling glass that killed a pedestrian. The $1 million throw will cover the inside of each window with a thick adhesive film, anchored to the building with a metal frame, which would detain pieces of broken glass in place until a permanent repair is made. CNA hired the Northbrook, Ill.-based engineering firm