How Material Choice Impacts Inlet & Frame Durability

Gratings, including roadway inlets and frames, are critical yet often-ignored infrastructure components. If they’re not manufactured correctly, the risk of flooding or, at worst, serious injuries increases.

One factor that determines the durability and resilience of these components is the material used in manufacturing. In this article, we’ll explore why.

Corrosion Resistance & Environmental Performance

Steel, particularly carbon steel, is often preferred when manufacturing grating because it’s affordable and strong. The downside is that it’s not corrosion-resistant like stainless steel or aluminum. If the grating is to be used in an outdoor application or in a corrosive environment, hot-dip galvanized steel is used. In this process, the carbon steel undergoes galvanization, in which a protective zinc coating is applied. Instead of steel degrading over time, the zinc coating slowly degrades over several decades, keeping the steel safe and protecting the overall structure.

Load Distribution

Carbon steel offers the highest strength-to-thickness ratio, so even thinner profiles can still meet heavy-load requirements. This is why carbon steel is the preferred choice for roadway inlets and other steel grating that’s expected to perform reliably under heavy traffic and truck loads.

Carbon steel’s higher modulus of elasticity also means less deflection under load, so even under heavy traffic, the frames within the grating system maintain position and don’t sag, preventing ineffective drainage and potential flooding.

Maintenance Needs

In terms of impact, maintenance is low on the list. Load requirements and environment should always be the higher-priority factors when determining the material used for grating.

The maintenance needs for carbon steel, stainless steel, and aluminum vary depending on the environment they’re used in. In outdoor applications, stainless steel offers the most corrosion resistance, followed by aluminum, so they need to be maintained less frequently.

Bare carbon steel would never be recommended for outdoor applications—it’s always galvanized. Galvanized carbon steel does have to be recoated (or replaced, depending on the level of damage) once the zinc coating degrades, but unless the carbon steel is used in a highly corrosive industrial environment or in an area where salt is frequently broadcast on highways, it would take decades before that’s necessary.

Best Use Cases for Common Grating Materials

Carbon Steel (Galvanized)

Galvanized carbon steel is the best option for roadway applications because it has the highest load-bearing capacity, is readily available and easy to fabricate, and isn’t as expensive as aluminum or stainless steel.

Aluminum

If the grating is used in a marine or coastal environment and weight-critical applications, like on a boat ramp or boardwalk, then serrated aluminum could be the best option because it’s lightweight and provides excellent saltwater corrosion resistance. It shouldn’t be used in applications requiring high strength or in areas that require frequent cleaning, such as meat, poultry, or seafood processing.

Stainless Steel

Stainless steel is expensive, but it may be necessary for applications that prioritize corrosion resistance and sanitation, such as in the food processing and medical industries. Stainless steel also offers high-temperature resistance, so it’s often recommended for environments that frequently experience extreme heat, such as around thermal processing equipment or in steam plants.

Speak With an Expert Today

Laurel Custom Grating manufactures and supplies ready-to-ship, PennDOT-approved, carbon steel roadway grates and frames, as well as custom options for precast or cast-in-place drainage boxes and troughs.

All grating we produce is made in the U.S. with domestically sourced materials.

Visit our website to learn more about our solutions, or contact us today if you need help determining which grating material is best for your specific project.