Iron Grating
Iron grating — typically manufactured from ductile iron (nodular cast iron) or grey cast iron — is the industry standard for municipal drainage systems, gully covers, tree grates, and heavy-duty trench covers.
Ductile iron offers excellent compressive strength and impact resistance, outperforming standard cast iron while providing superior corrosion resistance and a longer service life in harsh outdoor environments. Available in various load classes to meet EN 124 and EN 1433 standards.
Iron Grating Quick Specs
| Parameter | Range |
|---|---|
| Base Material | Ductile Iron (QT500-7) / Grey Cast Iron (HT200) |
| Load Class (EN 124) | A15 / B125 / C250 / D400 / E600 / F900 |
| Standard Dimensions | 300×300 / 400×400 / 500×500 / 600×600 mm (Custom available) |
| Grating Pattern | Slotted / Mesh / Square holes / Decorative (Tree grates) |
| Surface Treatment | Black Bitumen / Anti-Rust Paint / Hot-Dip Galvanized |
| Hinge & Locking | Optional concealed hinges, anti-theft locking bolts |
| Frame Compatibility | Unframed / Flanged frame / Angle frame |
Ductile Iron vs. Cast Iron
While both are iron-based, their microstructures differ significantly. Grey cast iron contains flake graphite, which makes it brittle and prone to cracking under heavy impact or dynamic loads. Ductile iron (also known as nodular iron) contains spherical graphite nodules, which gives it significantly higher tensile strength, yield strength, and impact resistance.
For modern municipal drainage covers and heavy-duty trench grates (especially C250 to F900), ductile iron is the strictly preferred material due to its ability to withstand heavy vehicle traffic without shattering.
| Property | Ductile Iron | Grey Cast Iron |
|---|---|---|
| Graphite Structure | Spherical (nodules) | Flake |
| Impact Resistance | High — bends rather than breaks | Low — brittle, prone to cracking |
| Tensile Strength | 500+ MPa | 200 – 300 MPa |
| Typical Application | Heavy vehicle roads, airports, tree grates | Pedestrian areas, light duty covers |
| Relative Cost | Higher | Lower |
Iron Grating Load Class Reference (EN 124)
Selecting the correct load class is critical for municipal iron grating. EN 124 defines the load-bearing capacity of gully tops and manhole tops. Ensure the class matches the installation area to prevent structural failure and ensure public safety.
| Class | Test Load | Typical Installation Area |
|---|---|---|
| A15 | 15 kN (1.5 tons) | Pedestrian areas, sidewalks, green belts |
| B125 | 125 kN (12.5 tons) | Footways, car parks, driveways |
| C250 | 250 kN (25 tons) | Roadside gutters, pedestrian streets with vehicle access |
| D400 | 400 kN (40 tons) | Carriageways, roads, hard shoulders |
| E600 | 600 kN (60 tons) | Ports, docks, heavy industrial areas |
| F900 | 900 kN (90 tons) | Airports, extreme heavy-duty areas |
Applications
Municipal Gully Gratings
Ductile iron gully gratings are standard for city road drainage. Available with concealed hinges for easy cleaning and anti-theft locking mechanisms. Slotted patterns are designed to maximize water intake while blocking large debris.
Tree Grates & Landscaping
Cast and ductile iron tree grates provide a durable, walkable surface around urban trees. They protect roots, allow water penetration, and offer a high-end architectural look for sidewalks and plazas. Available in round or square configurations with adjustable tree openings.
Trench Drains & Channel Covers
Heavy-duty ductile iron trench covers (Class D400/E600) for highways, ports, and industrial facilities. Designed to withstand continuous heavy vehicle traffic without deformation.
Quality & Supply
Load Testing Compliance — Iron grating can be supplied with third-party EN 124 load testing certification upon request to guarantee safety.
Material Traceability — Every heat number of ductile iron is recorded, ensuring the mechanical properties (spheroidization rate, tensile strength) meet QT500-7 standards.
Anti-Corrosion Coating — Standard black bitumen coating or anti-rust paint. Hot-dip galvanizing is available for enhanced corrosion resistance in coastal or highly humid environments.
Custom Framing — We manufacture matching frames (angle frames, flanged frames) to ensure a perfect fit and flush installation on site.
Related Products
FAQ
Iron Grating — FAQ
Why should I choose ductile iron over cast iron for road drains?
Ductile iron has a spherical graphite structure that gives it much higher impact resistance and tensile strength compared to grey cast iron. This means ductile iron covers can bend slightly under heavy vehicle loads without shattering, making them mandatory for modern road and highway drainage.
What does EN 124 load class mean?
EN 124 is the European standard for gully tops and manhole tops. The class (e.g., C250, D400) indicates the test load the grating and its frame can withstand (e.g., D400 = 400 kN test load). You must select a class appropriate for the traffic area where it will be installed.
Do you offer anti-theft iron grates?
Yes. We supply iron grating with concealed hinges and specialized locking bolts that require a special key to open. This deters theft while allowing municipal workers to clean the drains easily.
What surface treatment is best for iron grating?
Standard black bitumen or anti-rust paint is common for municipal projects. If the grating is installed in coastal areas, highly corrosive soils, or areas subject to frequent chemical exposure, hot-dip galvanizing is highly recommended to extend service life.
Need a Custom Iron Grating Specification?
Send your required dimensions, load class (e.g., C250 or D400), surface treatment, and quantity. Whether you need standard municipal grates or custom tree grates, our factory-direct team will provide a detailed quotation within 24 hours.