ZeAllgrate FRP Grating Covers — Complete Specifications
Closed-top FRP deck systems
Covered grating combines the structural depth of open grating with a closed walking surface for spill containment, hygiene and object exclusion.
Spill containment
A bonded cover plate prevents liquids, chips and objects falling through the open mesh into the process below.
Smooth / hygienic surface
No open mesh to trap dirt; easy to wash down — ideal for food & beverage and cleanroom environments.
Object & footfall prevention
Stops small tools, debris and trolley wheels dropping through, and reduces slip-through risk for pedestrians.
| Standard cover plate thickness | 3 mm (standard) · 5 mm (heavy / wheeled traffic) |
| Substrate grating | Molded 25 / 38 / 50 mm or pultruded 40 / 50 / 60 mm open grating |
| Standard panel size | 1220 × 3660 mm (molded) · 1200 × 3660 mm (pultruded); cut-to-size |
Select by open area, load and surface requirement
Load ratings are indicative pedestrian-service values after derating from the open-grating base deck.
| Cover Type | Description | Thickness | Weight (kg/m²) | Open Area | Load Rating (kN/m²) | Surface Options | Typical Use |
|---|---|---|---|---|---|---|---|
| Solid Cover (FRP plate bonded) | Solid FRP cover plate bonded to open grating deck | 3 mm plate over grating | ≈ 16 – 20 | 0% | ≈ 2.5 – 5.0 | Smooth / gritted | Spill containment, smooth walking surface, hygiene zones |
| Perforated Cover | Perforated FRP plate with controlled open area bonded to grating | 3 mm plate over grating | ≈ 15 – 19 | 10 – 20% | ≈ 2.5 – 4.5 | Smooth | Drainage still required; dust / object fall-through control |
| Covered Grit-Top | Grit-embedded cover plate over open grating | 3 – 5 mm plate over grating | ≈ 17 – 22 | 0% | ≈ 2.5 – 5.0 | Grit-top (anti-slip) | Wet / oily process areas requiring grip and spill containment |
| Solid Cover with Anti-Slip Pattern | Embossed / anti-slip ribbed solid cover plate | 3 – 5 mm plate over grating | ≈ 17 – 22 | 0% | ≈ 2.5 – 5.0 | Embossed / ribbed | Pedestrian areas, ramps, stairs landing, wheeled traffic |
| Mini-Mesh Covered | Fine 19 × 19 mm mini-mesh grating with bonded cover | 25 – 38 mm mini-mesh | ≈ 22 – 28 | ≈ 5 – 15% | ≈ 4.0 – 6.0 | Grit-top | Fine footfall prevention, cleanrooms, small-object exclusion |
Cover plate and laminate characteristics
Cover plate is pultruded or molded FRP in the matching resin system, resin-bonded to the grating with a chopped-strand polyester veil.
| Cover plate thickness options | 3 mm (standard) · 5 mm (heavy / wheeled traffic) |
| Glass content (cover) | ≈ 25 – 35% by weight (molded cover) / ≈ 60 – 70% (pultruded cover) |
| Bond (plate to grating) | Resin + chopped-strand veil; lap shear ≈ 8 – 12 MPa (typical) |
| Impact resistance | Cover plate absorbs surface impact; substrate grating retains structural span capacity |
| Fire performance | Self-extinguishing (ASTM D635); E84 ≤ 25 typical; E84 Class A / USCG options in ZeAll FR |
ZeAll ISO
General corrosion grade — water, mild acids/bases; self-extinguishing.
ZeAll VE
Harsh chemical resistance — acids, solvents, oxidisers; preferred for process industry.
ZeAll FDA
Food-contact grade resin (FDA 21 CFR) for food & beverage, dairy and cleanrooms.
Covered grating derates to ≈ 0.5 × the open-grating load
The bonded cover plate adds a composite action but also transfers load over a shorter tributary width and reduces ventilation; industry practice derates open-grating allowable loads by ≈ 0.5 for covered decks.
| Deck Configuration | Derating Factor | Indicative Allowable UDL (kN/m²) | Typical Use |
|---|---|---|---|
| 25 mm open grating (reference) | — | 1.0 × (open grating rated load) | Per certified chart |
| 25 mm covered grating (3 mm cover) | ≈ 0.50 × | ≈ 2.5 – 4.0 | Spill containment / hygiene |
| 38 mm covered grating (3 mm cover) | ≈ 0.50 × | ≈ 4.0 – 6.0 | Pedestrian platforms |
| 50 mm covered grating (5 mm cover) | ≈ 0.55 × | ≈ 6.0 – 9.0 | Heavier pedestrian / light trolleys |
Derating basis: ZeAllgrate (ACMA) engineering practice for covered/closed decks. Always design from the open-grating base load chart and apply the derating factor; confirm impact and wheeled-traffic cases separately.
Where covered grating is specified
Food & beverage
Hygienic, wash-down surfaces in dairies, breweries, processing lines — ZeAll FDA resin.
Chemical spill containment
Closed decks over trenches, sumps and curbed areas to contain drips and leaks.
Cleanrooms
Smooth, non-shedding, easy-to-clean surfaces for microelectronics and pharma.
Pedestrian areas
Comfortable closed walking surface where open mesh is undesirable or a trip hazard.
Car parks & vehicle decks
Covered grit-top for light vehicle / trolley traffic and drainage control.
Transformer platforms
Closed top prevents conductive objects falling onto live electrical gear.
Covered grating assembly — cover plate bonded to open grating
Schematic, not to scale.
Bonding, edge sealing, clips and cut-outs
Bonding
Cover plate is factory-bonded with matching resin + chopped strand; site field-bond cover strips around cut-outs.
Edge sealing
Seal all cut edges and plate-to-grating joints with matching resin to prevent chemical wicking.
Clip mounting
Fasten like open grating — SS316 clips at every bearing-bar / support intersection; minimum 4 clips per panel.
Cut-outs
Radius all cut-out corners, reinforce with FRP angle banding around the opening, and re-seal edges.
Covered-grating load values are indicative and derived from open-grating load charts with a ≈ 0.5 derating factor. Contact [email protected] for a project-specific covered-grating design and COA.
Cover Types Compared
| Cover Type | Construction | Best Service |
|---|---|---|
| Bonded plate cover | Closed FRP plate bonded to the grating panel | Spill containment, hygienic food/cleanroom decks, maximum closure |
| Molded cover panel | Compression-molded closed-top panel with integral surface | Drainage with closure; light spill control, pedestrian decks |
| Snap-in / clip-on cover | Separate cover plate retained by clips | Retrofit to existing open grating; removable for cleaning access |
Load Derating with Covers
Adding a cover changes the panel's structural behaviour and the load tables must be read accordingly. A bonded plate increases the panel's stiffness and spreads point loads, but the combined section's capacity is verified against the panel manufacturer's covered-panel data — do not simply apply the open-grating table. Where the cover is a separate plate, the open grating carries the load and the plate is a closure member; check the plate for point loads (foot traffic, trolley wheels) and the grating for the full design load. Cover panels with reduced opening (e.g. mini-mesh) also have their own table, read at the same deflection limit.
Hygienic Design Details
- Closed top — no open mesh to trap product, chips or debris; washdown reaches the whole surface.
- Fully drained option — covered panels can be specified with small drainage holes or channels where standing water is unacceptable.
- Sealed edges — bond lines and cut edges are sealed to prevent wicking and bacterial harbourage.
- Grit-top on cover — specify grit on the cover surface for wet washdown areas; slip safety applies to the closed surface too.
- Inspection access — plan removable sections above process equipment before the deck is closed over.
- Closed top — no open mesh to trap product, chips or debris; washdown reaches the whole surface.
- Fully drained option — covered panels can be specified with small drainage holes or channels where standing water is unacceptable.
- Sealed edges — bond lines and cut edges are sealed to prevent wicking and bacterial harbourage.
- Grit-top on cover — specify grit on the cover surface for wet washdown areas; slip safety applies to the closed surface too.
- Inspection access — plan removable sections above process equipment before the deck is closed over.
Approved by Industry Bodies, Tested to International Standards
Every ZeAllgrate shipment is backed by documented quality systems, marine approvals and independent third-party verification.
ISO 9001:2015
Certified quality management system — since 2004.
DNV & ABS Marine
Marine-grade grating for offshore platforms and vessel decks.
SGS & Intertek
Independent third-party inspection and load testing on request.
OSHA 1910.23
Handrail systems load-tested to US federal requirements.
Material certificates, COA, ASTM test reports and compliance documentation supplied with every order. View certifications →
Need a Covered Grating Design?
Tell us your media, load, wheeled-traffic case and hygiene requirements — we specify cover type, thickness and resin within 24 hours.