... BS4592, AS1657, JS3101 1.3 Grating Dimension Load Bearing Flat Bar sizeThickness≥3mm, depth ≥19mm19X3,19X5,20X3, 20X5, 25X3, ... …..40X6, 40X8, 40X10,….90X6….Pitch of Load bearding flat bars(mm)12.5,15, 20, 30, 30.6, ... .8, 35.3, 40, 60, 80……Pitch of cross bars(mm)38.1, 50, 50.8, 70, 75, 80 ... serrated I type; cross bar: round type and square twisted type. Square twisted cross bars are mostly used.And round ...