Suitable for use as a fire resistant floorlight or rooflight. The visual appearance is similar to R254/B191 from our standard range. This construction provides clear spans up to 3300mm when installed as a floorlight for pedestrian loadings of 4kN/m². Contains BG1990 high performance fire resistant glass blocks 190 x 190 x 160mm set into reinforced concrete ribs which are spaced at 254mm centres with an overall panel thickness of 160mm. Weight- 285 kg/m². In the interests of safety we recommend that when used as a floorlight, the glass blocks are sandblasted to the top surface to increase slip resistance.