Manhole cover facilities are divided into the following six levels according to the carrying capacity: A15, B125, C250, D400, B600, F900.
Manhole cover facilities are divided into the following six groups according to the place of use:
The first group (at least A15 level): green belts and other areas where motor vehicles or non-motor vehicles are completely prohibited:
The second group (at least B125 level): sidewalks, pedestrian areas, non-motorized vehicle lanes, small parking lots
The third group (the lowest level of C250): motorized vehicle lanes within 0.5m of the curb or non-motorized vehicle lanes within 0.2m of the curb, and residential quarters, inner streets and other areas with few light motor vehicles or small vehicles. :
The fourth group (at least D400 level): suitable for urban motor lanes, expressways, high-grade highways, and highways where all types of vehicles pass.
Expressways, large parking lots and other areas:
The fifth group (e600 lowest): freight station, logistics area, wharf and other areas:
The sixth group (at least F900 level): applicable to the airport area.
