- FRP (fiberglass reinforced plastic) grating does not rust, is light and non-conductive.
- Molded grating has equal strength in both directions and excellent corrosion resistance.
- Pultruded grating spans further and carries heavier loads in one direction.
In chemical plants, effluent treatment areas, cooling towers and coastal sites, steel grating can corrode within a few years. Fiberglass reinforced plastic (FRP or GRP) grating is a long-lasting alternative that needs no painting and weighs a fraction of steel.
Molded FRP grating
Molded grating is made by laying continuous glass fibre rovings in a square mesh mould and saturating them with resin. The result is a one-piece panel with roughly equal strength in both directions and a high resin content, which gives very good corrosion resistance. Panels can be cut on site with minimal loss of strength, which makes them practical for walkways, trench covers and platforms with many cut-outs.
Pultruded FRP grating
Pultruded grating is assembled from bars produced by pulling glass fibres through a resin bath and a heated die. The bars, usually I or T shaped, are held together by cross rods. The high glass content along the bar makes pultruded grating stiffer and stronger in the span direction, so it suits longer spans and heavier loads, such as platforms for equipment access.
Side by side
| Molded | Pultruded | |
|---|---|---|
| Strength | Equal in both directions | High in one direction |
| Span | Shorter spans | Longer spans |
| Corrosion resistance | Excellent, resin rich | Very good |
| Cutting on site | Easy | Needs care with bar ends |
| Typical use | Walkways, trench covers, wash areas | Platforms, heavier foot and cart traffic |
Choosing the resin
- Orthophthalic polyester: economical, for mild environments.
- Isophthalic polyester: better chemical resistance for general industry.
- Vinyl ester: for strong acids, alkalis and harsh chemical exposure.
- Fire-retardant formulations where flame spread ratings are required.
Details to specify
- Clear span and the load: uniform foot traffic or point loads from carts and equipment.
- Allowable deflection, which is often the governing check for FRP.
- Panel depth and mesh size; finer mesh for areas with small tools or heels.
- Surface: gritted anti-slip top for wet or oily floors.
- Colour, UV protection for outdoor use, and stainless steel or FRP clips for fixing.
Apex Engineers produces FRP grating and fiberglass products for industrial and infrastructure projects. Share your layout and loads and our team will recommend a grating type.
Written by the Apex Engineers team
Engineers and fabricators at Apex Engineers (Pvt.) Limited, building fuel stations, storage tanks, steel structures, towers and road safety systems from our Lahore manufacturing facility since 1992. About us
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