All 12" Internal Width Grates Home » Products » Trench Drains » Grates » 12" Internal Width Grates 12" Internal Width Grates Subcategories Load Class C: EN 1433 - 56,200 LBS., 250kN, 1160 PSI Load Class E: EN 1433 - 134,800 LBS., 600kN, 2785 PSI Load Class F: EN 1433 - 202, 320 lbs., 900kN, 4,177 PSI