In municipal engineering, ductile iron gully gratings serve as core components for road drainage. Their design and selection must strictly adhere to standards and match operating conditions to ensure drainage efficiency, traffic safety, and service life.

1. Core Design Standards: Regulating Performance and Safety Baselines

(1) Fundamental Specifications

Domestically, they must comply with the Code for Construction and Acceptance of Municipal Drainage Pipeline Engineering and Cast Iron Manhole Covers. For export or international projects, reference should be made to the European Standard EN 124:2019, 'Gully Tops and Manhole Tops for Roads and Pedestrian Areas ', to ensure compatibility with globally accepted norms.

(2) Load Classifications

Classified by traffic pressure:
Light-duty: Suitable for sidewalks and pedestrian streets.
Medium-duty: Applicable to residential main roads and municipal branch roads.
Heavy-duty: Designed for urban arterial roads and freight corridors.
Higher grades: Used in ports and industrial zones.

(3) Drainage Performance

The design must ensure the opening rate meets drainage requirements: For municipal roads, the opening rate of gully gratings is generally no less than 30%, and for rain-prone areas or low-lying road sections, it should be increased to over 35% to prevent rainwater accumulation. Additionally, the water inlets of the gratings must match the cross-slope and longitudinal slope of the road to ensure rapid water inflow and reduce the risk of road surface ponding.

(4) Structural Safety

The gap between the grating and the frame shall not exceed 3mm. The surface shall undergo anti-slip treatment, and anti-theft latches and anti-fall nets shall be equipped to ensure safe use.

(5) Material Performance

Ductile iron used shall have a tensile strength of ≥420MPa, yield strength of ≥300MPa, and elongation of ≥10%. Anti-corrosion requirements must be met: Hot-dip galvanized layers or epoxy resin coatings shall comply with thickness specifications, ensuring a service life of ≥15 years.

2. Key Selection Criteria: Matching Scenarios and Practical Needs

(1) Road Type and Load

Sidewalks: Select light-duty gratings.
Residential/municipal branch roads: Adopt medium-duty gratings.
Arterial roads and freight corridors: Require heavy-duty or higher-grade gratings, with grating thickness ≥15mm and frame wall thickness ≥12mm.

(2) Environment and Corrosion Risk

Ordinary road sections: Use standard hot-dip galvanized gratings.
Coastal/industrial zones: Choose gratings with double anti-corrosion (epoxy resin + hot-dip galvanizing) or those with cement slurry coating on the inner wall.
Green belt surroundings: Gratings can be equipped with nylon filters to prevent clogging.

(3) Cost and Maintenance

Long-term projects: Opt for high-grade gratings—though initial costs are higher, they offer longer service life.
Temporary projects: Economical models can be selected.
Prioritize gratings that can be opened without special tools for convenient sludge cleaning and maintenance.

In summary, design must be anchored to standards, while selection should focus on "load adaptation, efficient drainage, environmental resistance, and reasonable cost." This ensures that gully gratings not only fulfill their drainage function in the road system but also guarantee long-term traffic safety and stability.