According to Article 4 of GB/T23858-2009 "Inspection of Ductile Iron Grating for Manhole Covers," the ductile iron grating, ductile iron manhole grate, ductile iron rain grate, ductile iron manhole cover grate, ductile iron grating manufacturer - Shandong Lu Rong Material Co., Ltd. ductile iron manhole cover grate is divided into six grades based on load-bearing capacity.

(Select Type A15): Areas such as green belts and sidewalks where motor vehicles are prohibited from entering.

(Select B125 Type): Pedestrian walkways, non-motorized vehicle areas, small car parking lots, and underground parking lots. (Select C250 Type): Residential communities, alleyways, areas with only light motor vehicles or small cars, and within 0.5 meters of curb stones on both sides of roads with ductile iron gratings for stormwater. Fourth Group: (Select C250 Type): Urban main roads, highways, expressways, and other areas.

Group 5 (Optional E600 Type): Characteristics of cargo stations, docks, stainless steel ductile iron manhole grates, and their advantages in waste water discharge, as well as in airport areas.

Group 6: (Optional F900 Type): Airport runways and similar areas. Product Grade: Grade Mark Setting Event Lightweight Q - Oasis, alley, bicycle lane, or pedestrian walkway to prevent motor vehicles from entering; Standard P - Roads or parking areas for vehicles of Category 10 and below; Heavy Z - Roads or parking areas for motor vehicles; Cast Iron Manhole Cover Gratings - Protective devices used to cover deep wells on roads or at home, preventing people or objects from falling.