... 30and 40mm are recommended2) Cross bar pitch may be 30, 38, 50, 76 and 100mm; of which 50 and 100mm arerecommended3 ... , 30, 30.16, 30.3, 32.5, 34.3, 35, 38.1, 40, 41.25, 60, 80mm etcUS standard: 19-w ... ,Germany: DIN24537-1-2006, Japan:JIS galvanized steel grating ladder (factory)