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FRP Grating Case Study | Cleanroom Raised Subfloor — ZeAllgrate

Anti-static molded FRP grating as raised subfloor under cleanroom equipment

Project Overview

Microelectronics & Cleanroom — Project Background

A Class 1000 (ISO 6) microelectronics cleanroom required a raised subfloor beneath its process equipment, under the raised access floor tiles. The subfloor had to support the weight of process tools and maintenance carts, provide safe access to under-floor utilities (power, gas, exhaust), and — critically — dissipate static electricity so that technicians and carts could not generate electrostatic discharge (ESD) that would damage wafers. Standard steel grating was rejected because it can rust and shed particles; aluminum was rejected because it can outgas and is not inherently anti-static without a conductive coating that wears off.

Engineering specified anti-static (conductive) molded FRP grating with a controlled surface resistivity, non-outgassing resin, and smooth edges that do not shed particles. Client identity is kept confidential; the project is described as Confidential Client, a semiconductor wafer fabrication facility.

Design Parameters

Engineering Specification

Working values agreed with the client's engineering team during design review.

ParameterSelected ValueStandard / Reference
Live load3.0 kN/m² (maintenance carts + tools)Cleanroom equipment design basis
Clear span0.9 m between pedestalsZeAllgrate molded grating design guide
Deflection limitL/150 at design loadZeAllgrate standard
Resin systemZeAll anti-static (conductive additive)ESD control / non-outgassing
Surface resistivity10⁶ – 10⁹ Ω/sq (static-dissipative)ESD Association / cleanroom spec
Panel thickness38 mm molded, mini-meshZeAllgrate standard molded grating
MeshMini-mesh 19×19 mmUtility access + particle control
SurfaceSmooth, post-cured and washedNo particle shedding
OutgassingLow-outgassing resin systemClass 1000 cleanroom requirement
FixingsConductive SS304 clips (grounded)ESD continuity to ground
Solution & Installation

What Was Supplied and How It Went In

ZeAllgrate supplied 750 m² of 38 mm anti-static molded FRP grating in mini-mesh 19×19 mm, post-cured and washed before dispatch to remove all resin dust and processing residues. Each panel was delivered with a batch surface-resistivity certificate showing 10⁶–10⁹ Ω/sq, and the conductive SS304 clips were bonded to the under-floor ground bus so the whole subfloor forms a continuous ESD path. The smooth, non-outgassing surface does not shed particles like steel grating would, and the open mesh lets technicians reach under-floor valves and cable trays without lifting access floor tiles.

Installation was completed in a two-week construction window between cleanroom fit-out phases, with panels hand-carried because the subfloor area was not yet rated for crane access. All cut edges were sealed in the factory to prevent glass-fiber shedding into the cleanroom air stream.

Anti-static mini-mesh molded FRP grating for cleanroom subfloor

Anti-static mini-mesh molded FRP grating for cleanroom subfloor

Factory-cut FRP grating panels with sealed edges

Factory-cut FRP grating panels with sealed edges

38 mm molded grating with smooth non-outgassing surface

38 mm molded grating with smooth non-outgassing surface

Results & Performance

Outcomes and Inspection Findings

At 1-year inspection, the cleanroom operator reported stable surface resistivity, no particle shedding, and no outgassing issues in routine air-sample tests. The subfloor has made under-floor maintenance faster because technicians can stand on the open grating instead of lifting and replacing access floor tiles.

  • ESD control: surface resistivity held at 10⁶–10⁹ Ω/sq at 1-year inspection; continuous ground path via conductive clips.
  • Cleanliness: no particle shedding from sealed edges; no outgassing detected in routine cleanroom air sampling.
  • Access: open mini-mesh lets technicians reach under-floor utilities without lifting access tiles; maintenance time reduced.
  • Corrosion: immune to cleanroom chemicals and humidity; no rust shedding.
  • Service life: expected 20+ years vs. 5–7 years for painted steel subfloor in cleanroom service.

Engineering Notes

Cleanroom subfloors are specified for non-conductivity, low shedding and stiffness under vibration-sensitive tools: FRP grating removes the earthing burden of a metallic subfloor, smooth covered surfaces are specified where particle control matters, and the deflection limit is applied strictly so the deck stays stiff under tool loads. Vinyl ester is specified where etchants and acids store or flow beneath the fab. Panel orientation and cut-outs are coordinated on the fabrication drawing so the subfloor supports the tool layout exactly.

What to Specify

  • Non-conductive molded grating; smooth/covered surface where particle control matters.
  • Deflection limit applied to the mezzanine grid; stiff under tool loads.
  • Vinyl ester where acids/etchants contact the deck.
  • Fabrication drawing coordinated with the tool layout.
  • Non-conductive molded grating; smooth/covered surface where particle control matters.
  • Deflection limit applied to the mezzanine grid; stiff under tool loads.
  • Vinyl ester where acids/etchants contact the deck.
  • Fabrication drawing coordinated with the tool layout.

Planning a Similar FRP Grating Project?

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Sources & References
  • ZeAllgrate molded grating design guide, load and deflection tables.
  • ESD Association ANSI/ESD S20.20 — electrostatic discharge control program.
  • IEST-RP-CC012 — cleanroom housekeeping and material outgassing guidance.
  • ISO 14644 — cleanroom and associated controlled environments classification.
  • Project inspection records supplied by Confidential Client; values quoted as-reported.