... 40, 60mm, of which 30mm & 40mmare recommended. 3)Cross bar pitches can be 38, 50, 60,100mm, of which 50mm ... trench cover, drainage pit cover, maintenance platform, pedestrian/crowded pedestrian, factory, workshop, motor rooms, trolley channel, heavy loading area, boiler ... width of bearing bar. Cross bar surface should not surpass bearing bar surface 1mm, beginning & end of cross bar should not surpass ...