FRP Grating Case Study | Offshore Helideck Perimeter & Walkways — ZeAllgrate
Oil & Gas / Offshore — Project Background
An offshore production platform in the South China Sea needed replacement walkways around the helideck perimeter, pump rooms and primary escape routes. The existing steel grating corroded rapidly under continuous salt-spray, and its weight was consuming the platform's topside weight budget — every kilogram removed was a direct saving on lifting capacity and ongoing payload. A further constraint: escape routes had to use low-smoke, flame-retardant materials to platform fire code, and all walking surfaces had to be non-sparking in hazardous equipment areas.
The operator specified pultruded rather than molded grating for long spans and higher live load, with marine-grade stainless fixings. Client identity is kept confidential; the project is described as Confidential Client, an offshore oil and gas operator in the South China Sea.
Engineering Specification
Working values agreed with the client's engineering team during design review.
| Parameter | Selected Value | Standard / Reference |
|---|---|---|
| Pedestrian live load | 5.0 kN/m² (offshore safety factor) | API RP 2G / platform design basis |
| Clear span | 1.2 m between supports | ZeAllgrate pultruded grating design guide |
| Deflection limit | L/200 at design load | ZeAllgrate / API pultruded grating |
| Resin — general areas | ZeAll FR (fire-retardant vinyl ester) | ASTM E84 flame spread < 25 |
| Resin — escape routes | Phenolic (low smoke, low toxicity) | IMO FTP Code Part 5 / ABS guide |
| Reinforcement | E-glass rovings + continuous mat, pultruded | ZeAllgrate PR series equivalent |
| Panel type | ZeAll Pultruded, 50 mm depth | ZeAllgrate pultruded grating |
| Surface | Grit-top bonded to bearing bars | Wet / oil-spill anti-slip |
| Fixings | SS316 (marine grade), all fasteners SS316 | ASTM A276 / A479 316 |
| Fire compliance | ASTM E84, IMO FTP Code Part 5 | ABS Guide for FRP Applications |
What Was Supplied and How It Went In
ZeAllgrate engineered and supplied 420 m² of 50 mm ZeAll Pultruded grating, split between ZeAll FR vinyl ester for general walkways and phenolic panels for the primary escape routes. All panels were pre-drilled, marked by area, and shipped as a bolt-together kit so installation could proceed without hot work on a live platform. Grit-top surface was bonded to all bearing bars for oil-spill anti-slip performance.
Total installed weight was approximately 75% lighter than the equivalent steel grating system, saving roughly 8 tonnes of topside weight. Crane lift time during installation was reduced because each panel was light enough for two technicians to handle, eliminating the need for repeated heavy lifts over the helideck.
Pultruded FRP grating deck on offshore production platform
Helideck perimeter walkway with marine-grade FRP grating
50 mm pultruded grating panels for long offshore spans
Outcomes and Inspection Findings
The system met ABS fire requirements for helideck perimeter and escape routes, with flame spread and smoke density tested per ASTM E84 and IMO FTP Code Part 5. At 3-year inspection, ZeAllgrate and the operator jointly reported zero corrosion on panels and SS316 hardware, and no delamination or loose fixings.
- Fire & smoke: phenolic escape-route panels passed low-smoke requirements; ZeAll FR panels held flame spread < 25 per ASTM E84.
- Corrosion: zero salt-spray corrosion after 3 years in South China Sea service.
- Weight: ~8 tonnes topside weight reduction vs. the previous steel system.
- Safety: non-sparking FRP bearing bars improved safety in hazardous equipment zones; no hot work required during replacement.
- Installation: bolt-together kit cut crane lift time and allowed work during a planned maintenance window.
Engineering Notes
Helideck perimeter and walkway service combines class-rule compliance, seawater splash and fire performance: the laminate and resin are specified against the DNV/ABS requirements, fire performance data is confirmed for the grade, and vinyl ester is used in the splash zones. Manufacturing QC and batch traceability are supplied so the installed product matches the certified data, and SS316 hardware carries the fixing in the marine atmosphere. The non-conductive, non-sparking construction suits the hazardous platform environment.
What to Specify
- Laminate and resin per DNV/ABS class rules; fire performance data supplied.
- Vinyl ester in splash zones; SS316 hardware throughout.
- Design to class load and deflection criteria.
- Manufacturing QC and batch traceability documentation.
- Laminate and resin per DNV/ABS class rules; fire performance data supplied.
- Vinyl ester in splash zones; SS316 hardware throughout.
- Design to class load and deflection criteria.
- Manufacturing QC and batch traceability documentation.
Planning a Similar FRP Grating Project?
Send us your layout drawings, service chemicals and span requirements — ZeAllgrate will return a design proposal, load calculation and reference pricing within 48 hours.
- ZeAllgrate pultruded grating design guide, load and deflection tables.
- ASTM E84 — Standard Test Method for Surface Burning Characteristics of Building Materials.
- IMO FTP Code Part 5 — Fire test procedures for flame spread and smoke.
- ABS Guide for Fiber-Reinforced Plastic (FRP) Applications, offshore and marine.
- API RP 2G — Recommended Practice for Helideck Design and Construction.
- Project inspection records supplied by Confidential Client; values quoted as-reported.