... installation,sturdy and durable, ventilated Steel Grating /Steel grid 1) Light weight, great load-bearing capacity, non-slip and ... , ventilates and light through facility, etc.4) category: 1.common steel flat grates,2.I shape steel flat grates, 3 ... steel, aluminumSurface treatmentUntreated, hot galvanized, paintedStandardsChina: YB/T 4001.1-2007USA: ANSI/NAAMM(MBG531-88)UK: BS4592-1987Australia: AS ...