Where arrival quality begins

Most early damage to grating is not caused in service but left behind by transport and storage. Battered edges, scratched surfaces and local crushing are already there before installation, and once the panel is in use it is hard to tell whether the supplier or the site caused them.

A 1.22 by 3.66 metre molded panel usually weighs only a few tens of kilograms, so two people can lift it, but the sheet is large and has limited stiffness; a point load distorts the whole panel and the corners take the damage first. Packaging is not decoration: its job is to keep force and moisture away from the panel.

Packaging and storage also affect long-term behaviour. A panel that has been crushed or kept damp already carries micro-cracks in the surface resin, and ageing starts from those points once it is in service. For how the material behaves over a long life, see FRP grating service life

Bundling, corner protection and pallets

Panels normally leave the works grouped by size, thickness and colour, several to a bundle and secured with PET strapping or steel band. The strap must not bear directly on the grating surface; corner protectors, timber battens or hardboard spread the load across several bearing bars.

Strap tension has to be enough but not excessive. Too tight leaves marks in the surface resin, and crushed grit does not recover; on a long sea voyage the straps also slacken with changes in temperature and humidity, so tension is checked again before loading.

Pallets must be flat with no nail heads standing proud. A grating panel is large and light, so a small bump on the pallet presses a hollow into the face. Export projects also need timber pallets that meet ISPM 15 fumigation or heat treatment, as the destination country requires.

Lifting and manual handling

Use wide slings for lifting and never choke a panel with wire rope. Wire rope touches the edge over a tiny area, and the concentrated force at pick-up is enough to cut a bearing bar or crack a node, damage that often cannot be seen after the lift and only appears when the panel takes load.

The number of lift points follows the panel length: at least two on a short panel and four or a purpose-made spreader on a long one. The shallower the sling angle to the panel, the greater the horizontal force on the edge, so fit a spreader bar whenever one is available.

For manual handling, two people carry the long edges at the same pace; one person should not drag a panel. Dragging wears the grit, frays the edges and grinds site grit into the surface. A flat trolley is fine for short moves if it is padded, and the panels are never used as a walkway before installation.

Truck and container loading

Load panels flat. Do not stand them on edge against the side of a truck: the whole weight then sits on one narrow edge, and road vibration delaminates that edge and splits the banding, which is usually discovered at the receiving end.

When panels are stacked, put timber or hardboard between layers and line the battens up vertically. A misplaced batten concentrates the upper weight on one spot of the panel below, and a long journey leaves a bend that will not come out.

Leave ventilation gaps inside a container, especially for sea freight. A container swings through day and night temperatures, condensation forms on the panels and inside the wrapping film, and a long damp spell turns the resin surface chalky and lets mould grow where water sits on the grit. In a dry container, add desiccant bags and a vapour barrier inside the doors, and never use a pallet that has just been washed and is still wet.

UV and the storage environment

UV degrades the resin. A few weeks in transit and short storage do little, but months in the open leave the surface chalky and faded, and dark panels absorb more heat and run hotter. For the link between colour and weathering, see FRP grating colour and UV

The storage area should be level and well drained, ideally under a roof or shade cloth. Shade cloth needs an air gap; an airtight plastic sheet traps moisture against the panel, which then condenses and re-condenses as the temperature swings day and night.

Where open storage is the only option, tilt the panels slightly so rain runs off. A flat panel with a lifted edge collects water, and the wettest spot shows water marks and chalked resin first; the stack also needs dunnage underneath rather than sitting on the ground. A heat source or a reflective metal roof is equally unsuitable, because local heat speeds resin ageing.

Stacking height and support

There is no single stacking figure; it depends on panel depth, grating type and pallet capacity. Molded panels are flexible, so a tall stack slowly bends the lowest panel under its own weight, while pultruded panels are stiff along the bearing bar but have thin cross bars that damage easily under side pressure.

The usual rule is to stay within the maker's recommended stack height and to support the bottom layer on level ground or continuous dunnage. Spread the supports too far apart and the lowest panel behaves like a long span under uniform load, taking a permanent set over time.

For long storage, turn the stack or rotate the layers so no panel stays at the bottom throughout. Do not put steel pipe or scaffolding on top of a stack, and do not walk or stand on it.

What to inspect on arrival

Inspect as soon as possible after unloading, ideally while the carrier is still there. Check the panel count, size, colour batch and edge treatment, then look at every panel for battered edges, deep scratches and crush marks, and for grit that has come off in patches.

A light scratch usually does no harm, but a scratch that exposes fibre, a split edge or a cracked node is a structural defect; record it, photograph it and quarantine the panel rather than mixing it with good stock.

• Count the panels and check size and colour batch.
• Look along each edge, face and grit surface for exposed fibre.
• Sample length, width, thickness and diagonal deviation.
• Record the original packing condition and photograph any defect.

Shipping documents and batch numbers

The documents should include a packing list, sizes and batch numbers, resin type, inspection records, installation instructions and warranty terms. The batch number is the only thread that ties the delivered panels to the production record and the test report, so copy it at goods-in.

Where the project requires test reports, they must belong to that batch, not be a generic sample report. Check the test standard, the sample description and the issue date, and raise any missing item in writing.

Export projects also need a certificate of origin, a declaration of conformity or an inspection certificate, depending on the destination's clearance rules, and timber packaging must carry its fumigation or heat treatment mark. Missing paperwork causes port delays, and sun and rain at a port do more damage than the voyage itself.

Managing the store and common mistakes

Issue stock first in, first out so an early batch is not left at the bottom of the stack. Where panels stay on site for more than three months, add the store to the inspection round and record it with the post-installation inspections.

Do cutting and drilling in one campaign before installation and clear the swarf the same day, so it is not trodden into the grit. Seal cut and drilled edges on the day they are made; exposed fibre takes up water and becomes the starting point for ageing. For the working details, see FRP grating fabrication and cutting

The common mistakes are few: standing panels against a wall, lifting with wire rope, stacking pipe and scaffolding on the pile, storing in the open with no cover, and inspecting without photographs. None is serious alone, but together they can downgrade a good batch before it is ever installed.