Fire resistant building door - has interior sheet with cover forming central space filled with insulant and peripheral flange

摘要

The door has an interior sheet or casing (1) and a sheet or cover (2) between these and forming a central space which is filled with an insulant (3). The sheets are adjacent to the periphery to form a peripheral flange (4) with a first fold (5) forming an angle of 90 degrees. The two sheets (1,2) each have a similar length to the peripheral flange. The inner sheet or casing has a thinned zone (6) parallel to the extreme edge and found between the edge and the first fold is a second fold (7) on the peripheral flange which defines the two sheets.