... 100 WFG1.CERTIFICATE : ISO 9001:2008 quality system certificateINTRODUCTION TO COMMON STEEL GRATINGS:Bearing bar centers ... standards are available. The products most commonly used for Belt corridor, storage shelf,Attic panel, trestle, ... side full welding every 3 bearing bars. Notes for ordering:1. Please clearly state specifications, types, ... us. galvanized steel trench cover for rain draining system