FRP grating thickness selection depends primarily on anticipated uniform load, support span, and service environment. The recommendations below are derived from typical flexural behaviour of standard E‑glass/polyester molded panels tested per ASTM D790. For corrosive or elevated‑temperature environments, a phenolic resin system is commonly specified. Load performance varies according to span length, bar spacing, panel thickness, and grating configuration; a single universal load rating is not applicable across all installation conditions. Continuous operating temperature for polyester‑based FRP grating typically ranges from −40°C to 100°C, with higher short‑term excursions possible depending on the specific resin formulation and chemical exposure.
The following table provides general span‑to‑thickness guidance for preliminary design only. Final specification must be confirmed with manufacturer engineering data for the specific grating type, resin system, and installation conditions. Do not use these values as a substitute for project‑specific structural verification.
| Application | Maximum Span (mm) | Recommended Grating Type | Thickness (mm) | Typical Safety Factor | Data Reference |
|---|---|---|---|---|---|
| Light‑duty pedestrian walkway | 900 | Mini‑Mesh Grating | 25 | 3:1 | ASTM D790 |
| Standard pedestrian walkway | 900 | Molded Grating | 38 | 3:1 | ASTM D790 |
| Heavy pedestrian / light vehicle | 600 | Molded Grating | 50 | 3:1 | ASTM D790 |
| Heavy vehicle traffic | 600 | Heavy‑Duty Grating | 50+ | 5:1 | ASTM D790 |
| Corrosive environment walkway | 750 | Phenolic Grating | 38 | 3:1 | ASTM D790 |
Disclaimer: Span recommendations assume uniformly distributed load and a deflection limit of approximately L/180. Actual load capacity depends on panel dimensions, resin type, glass content, and boundary conditions. For concentrated loads, dynamic loading, or spans beyond those tabulated, consult FRP Grating Load Tables or request project‑specific engineering evaluation. Service temperature limits are resin‑dependent; verify the manufacturer’s continuous operating temperature for the selected resin system before specification.
For additional design methodology, see the FRP Grating Selection Guide.