... std. 3.independent AutoCAD design 4.ASTM A36 steel 1.Steel Grating Standardizations:CountriesNational Standards for GratingMaterialsGalvanizing Standards ChinaYB/T 4001 ... , 50mm, 75mm, and 100mm,101.6mm(4").5.Standard Grating Panels Sizes: 3'x12', 3'x20', 3'x24'.6 ... pit cover,stair tread,etc.Serrated:Better non-skid property & safety compared with plain grating.I-Shape:lighter,more economical ...