1>Bearing bar pitch:30,40,60mm 2>Cross bar pitch;50,100mm 3>Plain,Serrated,I-shape 4>Hot-dipped galvanized,Painted,Untrea Product 1.ISO9001:2008 management 2.US, UK or Australian std. 3.independent AutoCAD design 4.ASTM A36 steel1.Steel Grating Standardizations:CountriesNational Standards for GratingMaterialsGalvanizing Standards ChinaYB/T 4001.1-2007GB 700-88GB/T13912-2002AmericaANSI/NAAMM( ...