Molded FRP grating is cast from continuous glass strands and resin into a one-piece panel — cost-effective, corrosion-proof and strong enough for most industrial walkways.
- Best for: standard walkways, platforms and covers
- Choose molded for: low-cost corrosion-resistant flooring
- Key spec: ASTM load class, isophthalic resin, 25–50 mm
1. Manufacturing Process Overview
FRP molded grating is manufactured by casting continuous glass fiber strands and thermosetting resin in precision-heated metal molds. The process creates a one-piece, integrated grid structure with bidirectional strength. Key manufacturing parameters include mold temperature (140-160°C), curing time (8-15 minutes), resin injection pressure (2-4 bar), and glass fiber content (60-65% by weight).
2. Material Specifications & Standards
Standard molded grating panels are 1220mm × 3660mm, with thickness options of 25mm, 30mm, 38mm, and 50mm. Mesh sizes are typically 38×38mm or 40×40mm square opening. Resin systems include general-purpose polyester (ASTM D3299), isophthalic polyester (ASTM D3567), and vinyl ester (ASTM D4162). Glass fiber types include E-glass (electrical grade) and C-glass (chemical grade).
3. Mechanical Performance Data
38mm thick molded grating with 38×38mm mesh typically achieves: bending strength 180-220 MPa, tensile strength 280-320 MPa, compressive strength 120-150 MPa, elastic modulus 12-15 GPa, and Barcol hardness 40-50. Load capacity at 600mm span: pedestrian load 5 kN/m², medium load 10 kN/m², heavy load 15 kN/m². Deflection limit is typically L/200 per industrial standards.
4. Corrosion Resistance Performance
Vinyl ester molded grating demonstrates excellent resistance to 50% sulfuric acid (weight loss <2% after 90 days immersion), 30% sodium hydroxide (<1.5% weight loss), and most organic solvents. Isophthalic polyester performs well in mild to moderate chemical environments. Operating temperature range: -40°C to +80°C continuous, with intermittent exposure up to 120°C for vinyl ester systems.
5. 2026 Global Market Analysis
The global FRP molded grating market is projected to reach USD 1.85 billion by 2026, growing at a CAGR of 6.2% from 2024. Key growth drivers include: infrastructure modernization in developing economies, replacement of corroded steel grating in chemical plants, increasing demand from wastewater treatment sector, and growing adoption in renewable energy projects (solar farm walkways). Asia-Pacific dominates with 42% market share, followed by North America (28%) and Europe (20%).
Design Standards & Data Basis
All load, span and capacity values in this article are typical/indicative, derived from laboratory tests per NAAMM MBG-01 (FRP Grating Design Manual) methodology. Molded grating values apply a 5:1 factor of safety on ultimate capacity; pultruded grating values apply a 3:1 factor of safety, both measured at static ambient conditions. Impact loads are limited to 50% of stated values; long-term loads require creep adjustment per ASCE Structural Plastics Design Manual. Certified load tables, stamped engineering calculations and third-party test reports are available on request.
For structural sizing of your specific application, contact our engineering team with your load requirements, span and environmental conditions — we provide free structural calculations within 24 hours. Browse our molded grating and pultruded grating product pages for full specifications and resin options.
Typical Allowable Uniform Load (kN/m²) - Molded Grating
The table below consolidates typical allowable uniform live loads for molded isophthalic / vinyl-ester grating at a deflection limit of L/200, with a 5:1 factor of safety on ultimate capacity. Values are typical/indicative per NAAMM MBG-01; certified load tables are available on request.
| Model | Span 600 mm | Span 800 mm | Span 1000 mm | Span 1200 mm | Span 1500 mm |
|---|---|---|---|---|---|
| FG-M2538 (25 mm x 38x38) | 2.5-3.5 | 1.8-2.5 | 1.2-1.8 | 0.8-1.2 | 0.5-0.8 |
| FG-M3038 (30 mm x 38x38) | 4.0-5.0 | 2.8-3.8 | 2.0-2.8 | 1.4-2.0 | 0.9-1.4 |
| FG-M3838 (38 mm x 38x38) | 5.5-7.0 | 4.0-5.0 | 3.0-4.0 | 2.2-3.0 | 1.5-2.2 |
| FG-M3819 (38 mm x 19x19) | 6.5-8.0 | 4.8-6.0 | 3.6-4.6 | 2.6-3.5 | 1.8-2.6 |
| FG-M5038 (50 mm x 38x38) | 9-12 | 6.5-8.5 | 5.0-6.5 | 3.8-5.0 | 2.6-3.6 |
Typical/indicative values per NAAMM MBG-01; certified table on request. Ranges reflect resin system, mesh tolerance and fabrication variation. For forklift or truck traffic, use pultruded I-bar grating.
Model Naming: Thickness x Mesh Reference
ZEALL molded FRP grating is designated by panel thickness x mesh opening. The standard catalog covers four depths (25 / 30 / 38 / 50 mm) and three mesh sizes (38x38, 19x19, 50x50 mm). A typical designation is "38 mm Molded Grating x 38x38 mm mesh" (model code FG-M3838). Common references:
| Model code | Thickness | Mesh | Duty class | Typical use |
|---|---|---|---|---|
| FG-M2538 | 25 mm | 38x38 mm | Light | Drainage covers, light walkways |
| FG-M3038 | 30 mm | 38x38 mm | Medium | General walkways, ramps |
| FG-M3838 | 38 mm | 38x38 mm | Standard | Industrial platforms, standard service |
| FG-M3819 | 38 mm | 19x19 mm | Standard mini-mesh | Tool handling, heel-safe walkways |
| FG-M5038 | 50 mm | 38x38 mm | Heavy | Forklift areas, long spans |
| FG-P5038 | 50 mm I-bar | 38 mm bar spacing | Heavy pultruded | Heavy-duty platforms, truck traffic |
Typical Structural Parameters (I / S / E)
The table below gives typical flexural stiffness ranges for FRP grating profiles. Values are typical per NAAMM MBG-01 and are not a substitute for a certified mill test report. E depends on resin system (isophthalic polyester approx. 10-12 GPa; vinyl ester approx. 12-15 GPa); I and S scale with bar depth and profile shape.
| Profile | E flexural (GPa) | I (cm⁴ / m width) | S (cm³ / m width) |
|---|---|---|---|
| 25 mm molded grid | 10-12 | 2.5-4.0 | 2.0-3.2 |
| 30 mm molded grid | 10-12 | 4.5-7.0 | 3.2-4.8 |
| 38 mm molded grid | 11-13 | 8-13 | 5.0-7.5 |
| 50 mm molded grid | 11-14 | 16-26 | 8.5-13 |
| 50 mm I-bar pultruded | 12-15 | 55-85 | 22-32 |
Typical values per NAAMM MBG-01; certified values per project-specific mill test report on request.
Browse our product pages for full specifications: FRP molded grating.
Frequently Asked Questions
FRP (Fiberglass Reinforced Plastic) grating is a molded or pultruded fiberglass composite grid used for corrosion-resistant walkways, platforms and floorings. It combines glass fiber reinforcement with thermoset resin (polyester, vinyl ester, epoxy) for superior strength-to-weight ratio, zero rust and 20+ year service life.
