FRP Grating Solar Walkways for PV Maintenance

What a Solar Walkway Is — and What It Is Not

A solar walkway is an access route. On a photovoltaic array it usually runs between module rows, along a roof edge or from an access point to the equipment that has to be serviced. FRP grating gives that route an open, light and corrosion-resistant surface. It does not generate electricity, and it is not a walkable solar panel.

That distinction is worth stating because “solar walkway” is used for several different products. A walkable PV module is a module designed for foot traffic. A solar walkway in this page is a separate FRP route laid beside the modules, carried on the array rails or a dedicated frame. The array keeps its own modules, cables and mounting system.

The walkway is also not automatically a platform. A platform may carry equipment, guardrails or several people; a walkway normally carries one or two people with hand tools. Width, guarding, fall protection and the structural support follow the project’s layout and safety requirements, not the product name.

Why FRP Grating Suits a PV Array

Fiberglass-reinforced plastic is light for its strength, does not rust like steel and does not spark like metal. A 25 mm molded panel has a reference mass of 12.5 kg/m², so a 400 × 2000 mm piece weighs about 10 kg before packing and fixings. That matters on a roof where every kilogram has to be handled and where the array structure may already be fixed.

The open mesh lets water and dust pass through instead of collecting on a solid surface. It can be cut to narrow strips, which is useful when the space between module rows is much smaller than a standard panel. The same panel can be removed in sections where access to a module or roof equipment is needed.

Those advantages do not make FRP a universal answer. The material is non-conductive, but that does not make the whole installation electrically safe; bonding, earthing and clearances remain project requirements. The panel is light, but it still has to be supported and restrained. The mesh drains, but it can still hold dust or cleaning residue if the route is not maintained.

The Rail Layout Comes Before the Panel

On most solar walkways the panel sits on a rail or track that is already part of the array. The first question is therefore not “which thickness?” but “what does the panel land on?” The rail section, its direction, its spacing and the bearing width determine whether a cut piece can sit flat and whether the clip can reach the support.

The panel length is not the clear span. A 2000 mm piece can sit on rails 600 mm apart, or on two supports near its ends with a much longer unsupported middle. The clear span is the distance between the support edges. That, together with the load and the deflection limit, is what the panel has to be checked against.

A rail does not become a bearing support because the grating touches it. The clip connects the panel to the rail, but the rail and its fixings still have to carry the walkway load and any wind uplift. On a roof, the walkway should bear on the array rails or a dedicated support, not on the module glass or frame unless the module manufacturer and the project engineer have approved it.

Choosing 25 mm, 30 mm or 38 mm Molded Grating

The 25 mm, 38 × 38 mm molded panel is our usual light pedestrian starting point for solar maintenance routes. It is the configuration in the Indonesia order record below, cut into 400 × 2000 mm strips. It suits short supported runs where the route is used by maintenance staff with hand tools.

The 30 mm panel is heavier and stiffer, and the 38 mm panel goes further in the same direction. Neither is a guaranteed upgrade for every project: a thicker panel can still fail a deflection limit if the span is too long, and a thinner panel can be adequate if the supports are close enough. The right comparison is the same support layout, load and deflection limit with each candidate configuration.

Pultruded grating is the other direction. Its parallel bearing bars carry the main load along the bar direction, so it can suit longer, straighter runs when the supports run the right way. It is made to project dimensions and quoted per configuration. The molded versus pultruded comparison explains the structural difference; it is not a recommendation to choose one by name.

Load, Span and Deflection on a Solar Walkway

Start with the real use. One person walking carries a different load from two people with tool bags, a replacement module or a cleaning machine. A point load from a tool box or a ladder foot is different again. The project should state the load case it wants the walkway checked for, including any concentrated load and the deflection limit that matters to the users.

Then give the support layout. Mark the rails, their spacing, the bearing width and every unsupported opening. For a continuous run, say whether the panel is treated as a single span or as part of a continuous layout. A panel that is supported at three points does not behave like a simple two-support beam, and the difference belongs to the structural check.

We hold adopted load and deflection values for two 6 × 38 mm bar structures at 38 mm and 19 mm pitch, under stated single-span, short-term, room-temperature conditions. Those values are not a rating for every 25 mm or 30 mm panel. The bar geometry, support condition and material have to match before a figure can be used. The load and span guidance explains what the table does and does not cover.

Surface, Color, Resin and UV Are Separate Choices

The walking surface and the resin system solve different problems. Concave is the standard molded surface. Grit adds a rougher texture for wet, dusty or washed routes. Inlaid grit and milled surfaces are other options. A grit surface is not automatically a certified slip rating; if the project needs a slip test, state the method and the acceptance value.

Yellow is common on solar walkways because it makes the route visible against the roof and the modules. Color is a visibility choice, not a UV rating. Outdoor exposure can change the appearance of a colored panel, and color retention is separate from structural performance. UV exposure is addressed through the resin system and any specified protection.

Resin selection follows the actual environment. The economical base for the published price is isophthalic unsaturated polyester with alumina filler, for ordinary environments. Our experience with this formulation is about three years of service, with cracking from about one year; it is not suitable for strong corrosive service or a long-life target. Vinyl ester, epoxy and phenolic directions are quoted against the duty. The resin selection guide sets out the questions; the surfaces and treatments guide covers the walking surface.

Cutting Narrow Solar Strips Without Hidden Cost

Solar walkways often use narrow pieces because the gap between module rows is fixed by the array layout. A 400 × 2000 mm piece contains 0.8 m², but that is the area of the piece, not the area taken from a full sheet. How many pieces fit on a 1000 × 4000 mm or 1220 × 3660 mm panel, and how much is left as offcut, depends on the cut plan.

That is why cutting is priced on the delivered area with the actual sizes and nesting loss rather than on a universal cut charge per square metre. A quote that compares only the panel rate can miss the difference between a layout that uses the sheet well and one that produces a large amount of offcut.

Send the full piece list, quantities and any openings. We prefer factory cutting because the cut edges, drilled faces, piece marks and packing list can be checked together. Cut edges and drilled faces are sealed where the order requires it. An opening still needs support around the remaining cut bars; a hole is not a substitute for a bearing edge. The cutting and sealing guide covers the detail.

Fixing Panels to Solar Rails

M clips are the usual hold-down for a molded panel. They normally span two adjacent bars and are bolted through the panel to the support below. L clips bear on a single bar at lighter fixing positions. C clips normally join two adjacent panel edges. The letter describes a shape, not a fit: the jaw width, bolt centre and overall height have to match the panel and the rail.

The fixing layout comes from the support drawing. Rail spacing, wind uplift, edge zones, removable pieces and the need to reach the bolt from below all change the number and position of the fixings. We do not publish a universal clips-per-panel figure or a universal bolt torque. Those values are confirmed for the project and recorded on the approval drawing.

Galvanized steel is the economical choice for ordinary access areas. Stainless steel may be considered for coastal, chemical or wash-down exposure, but “stainless” covers a wide range of grades. Tell us the exposure and the support material so the clip and the panel are reviewed together. The clips and fixings guide explains the families and the fit checks.