The setting
A large chemical processing facility running continuous production. The main process walkways connect reactor blocks to storage tanks and the control room — elevated arteries that operators use every shift. Airborne acid fumes are a constant in this environment, settling on every surface. Steel doesn't stand a chance here long-term.
What was going wrong
The steel grating on these walkways had settled into a 24-month replacement cycle. Not surface rust — structural section loss at the welded joints, driven by condensation mixed with chloride-laden fumes. Each replacement meant scaffolding the walkway, pulling permits for hot work, and rerouting operators through temporary access routes. The maintenance team was essentially rebuilding the same walkways every two years.
What we installed
We started with the sections directly above the reactor discharge — the most aggressive exposure zone. The steel came out, and moulded FRG panels with a vinyl ester backbone built for acid service went in. Underneath, the support structure was switched to pultruded structural I-sections in FRP, keeping the entire assembly non-metallic. No coatings were applied because the corrosion barrier is the material itself, not a layer that degrades. The installation went into a regular maintenance window — no crane needed, which caught the site team off guard in a good way.
What changed
Bottom line: The 24-month steel replacement cycle is history. Three years of continuous service with no structural degradation. The plant has folded FRP into its capital replacement programme for the remaining steel walkway sections.
Replacement interval extended from 24 months to 3+ years. Dead load on the support structure dropped by 40% compared to the steel grating it replaced.
How it compares
Steel grating in this environment demanded a full replacement every two years — material cost, labour, scaffolding, and disrupted access routes each time. The FRP alternative carries a higher upfront material price, but the elimination of two replacement cycles over a six-year window more than offsets it, before you even account for the operational disruption avoided.
If this kind of corrosion problem sounds familiar, we've put together more detail in our corrosion prevention strategies overview. For other examples from chemical processing environments, see our coverage of walkway applications in chemical plants.