... 3' 4. 24'*3' Standard Steel Grating Panels Sizes in inch: 3x12, 3x20, 3x24 Standard Steel Grating Panels Sizes in mm: 1000x5800mm, 1000x6000mm ... , 914.4x6096mm, 914.4x7315mm. 1. Forge Welded Grating Standardizations:CountriesNational Standards ... , 75mm, and 100mm,101.6mm(4").5.Standard Grating Panels Sizes: 3'x12', 3'x20', 3'x24'.6 ...