Abstract: At least two generally parallel transparent panes are provided with a spacer between them at their perimeter, which spacer holds a fire protection material which includes an intumescent material, an opaque finely divided material in a solid, liquid or gel-like form. The fire protection material reacts at a certain temperature and expands by intumescence into the space between the transparent panes coating the internal surfaces of the transparent panes and rendering them opaque. The spacer itself may be composed of fire protection material or may be a channel holding such material or hollow tubular structure with openings or may be a combination of these forms. The invention also includes the method of placing fire protection material in the spacer between panes of glazing material and when temperature reaches a predetermined level expelling the fire protection material into the space between the panes and coating their internal surfaces with an opaque coating.