Structural sandwich plate members having improved fire-resistance

摘要

A structural sandwich plate member (10,20,30) comprises first and second outer plates (11,12) and a core of plastics or polymer material (13). A plurality of lightweight forms are disposed between the outer plates so that the core material forms ribs extending in two substantially orthogonal directions. The lightweight forms (14,24,34) are formed of a fire resistant insulating material, such as mineral wool, preferably surrounded by a barrier to prevent the insulating material being soaked by the liquid form of the plastics or polymer material during injection of the core. The barrier may take the form of a hollow tube (15) in which the insulating material (16,26,36) is placed or a coating (25) applied by dipping or spraying or a sheet material (35) such as metal foil, felt, mineral cloth or suitable plastics sheet.