1.Unrestrained tempered glass are to be laid flat on a table. Hold it in place by applying scotch tapes or other means around the perimeter to prevent the splash of shattered glass.
2. At a position of 20mm from the edge at the midpoint of the longest side of the sample, impacted with a pointed steel tool with a curvature radius of 0.2 mm ± 0.05 mm.
3.Counting should occur between 10 seconds and 3 minutes after the strike.
4.The counting of fragments shall exclude the pieces within a semicircular area with a 80 mm radius centered on the impact point and 25mm border along the perimeter. Select the largest piece of the fragment. On this piece, choose a 50mmx50mm area to count the number of particles. All particles wholly contained within the area should be counted as one fragment. Any fragment which is partially within the area should be counted as 1/2 a fragment.