... , defense project, chemical factory and so on.Steel grating standards:A) China: YB/T4001-1998 B) USA: ANSI/NAAMM ... bar centers at 30mm: Standard: American, Australian, Japan standards are available. Feature:This grating is featured well by heavy ... guardrail, sunshade gate, etc. Standard: British, German,French and Japanese standards are available. Notes: common welding standard: single-side full welding ...