What service life depends on

FRP grating has no single service life. Resin system, fibre type, surface finish, load conditions, chemical environment and routine maintenance all shape the actual life, and the same product behaves very differently from one site to another.

Resin is the main variable. Isophthalic resin resists water and chemicals better than orthophthalic, vinyl ester performs better in severe corrosion, and a surface veil or gelcoat slows UV and chemical attack.

Load and maintenance matter just as much. Long-term overload, loose fixings and unsealed cuts all shorten life, however good the resin.

Choosing the right resin and surface finish at design stage costs less than maintenance later. In a corrosive site, one grade up in resin is often cheaper than a shorter replacement cycle.

Reading the ageing signs

Chalking is the earliest sign. A pale surface that leaves powder on the hand means UV and rain are consuming the resin skin; the structure is usually still sound, but the surface protection is weakening.

Exposed fibre is the next stage. White or pale fibre patterns at the surface mean the resin has been eroded down to the reinforcement, and water can travel along the fibre interface.

Cracks, blistering and delamination need separate judgement. Blisters may come from permeation, a chemical reaction or process residue; cracks usually follow impact, overload, installation stress or thermal movement; delamination sounds dull when tapped.

Colour change alone is rarely enough to judge life. If a colour shift comes with chalking, exposed fibre or cracks, assess it properly and, where needed, take a sample or re-check the load capacity. Corrosion and weather resistance are covered under FRP grating performance

UV and chemical environment

UV acts mainly at the surface, while chemical attack can reach the resin and the fibre interface. Where the two combine, a chalked surface lets chemicals settle and permeate more easily.

Acids, alkalis, solvents and oxidisers each behave differently, and higher concentration and temperature accelerate attack. Selection should check the resin chemical resistance table against the actual medium, concentration and temperature, not against the word corrosion-resistant.

Occasional drips and continuous immersion are two different duties. In a chemical plant, watch drip points, drains and trenches, where grating usually ages first.

Corrosion can also differ within one plant. Grating under drip points, in wash-down areas and near exhausts needs its own assessment rather than one interval for the whole platform.

How to inspect

Routine inspection is mainly visual: unusual colour, chalking and exposed fibre, cracks and blisters, distortion of panels, and loose or corroded fixings.

Periodic inspection can add a tap test for delamination and, where conditions allow, a remaining-thickness measurement or a local load test. Record results by area so trends can be compared.

Look separately at critical areas: tread nosings, around openings, fixing points, cut edges, chemical drip points and drains. Failure there usually runs ahead of the general surface.

Attach photographs and location numbers to inspection records. A series of photos of the same spot over several inspections shows the rate of ageing better than a written description.

• Tread nosing: check nosing wear and exposed fibre.
• Fixing points: check washer marks, cracks at holes and rust stains.
• Cut edges: check that sealing is intact and not whitening.
• Around openings: check frames and corners for cracks.

Repair or replace

Local defects can be repaired: clean, dry, abrade, apply resin and reseal. A repair restores surface protection, but colour and mechanical properties rarely return fully to the original.

Replace panels with a clear loss of load capacity, extensive exposed fibre, through cracks or spreading delamination. Base the decision on remaining capacity and duty, and be more conservative on escape routes and load-bearing platforms.

Repair resin must suit the original resin and cure as instructed. Mark repaired areas and include them in the next inspection rather than forgetting them. The link between grating grade and capacity is set out in the grating specification and grades

Find the cause before repairing. Where chemical attack keeps blistering a patch, surface repair soon fails again; stop the drip or move to a higher resin grade first.

Setting a maintenance plan

Set frequency by environment: once a year in ordinary atmosphere, every six months or less in chemical, coastal or hot and humid sites, and immediately after anything unusual.

The plan covers cleaning, inspection, tightening, repair and records. Clean with a neutral detergent and rinse residue away; re-tighten to the fastener requirement; schedule repair and replacement from inspection findings.

Write down who is responsible, the interval and the record format. Maintenance without records is hard to read as a trend and breaks down when staff change.

It helps to tie the maintenance plan to plant shutdowns. Concentrating inspection, cleaning and replacement during a shutdown is safer than scattered work in production and easier to resource.

• Cleaning: match the contamination, avoid strong acids and alkalis.
• Inspection: record chalking, cracks and fixing condition by area.
• Tightening: re-torque loose clips and bolts to the maker's figure.
• Repair: same resin system, reseal after repair.

When to replace a whole installation

Reaching a certain age does not by itself require replacement. Condition assessment is more reliable than a calendar; if capacity and appearance still meet the requirement, the installation can stay in service with a shorter inspection interval.

Signals for whole-area replacement include a clear rise in repair frequency, exposed fibre appearing in several areas at once, a capacity check that fails the current load, and appearance that undermines safety recognition, such as badly faded yellow warning edges.

Where whole-area replacement is more economic than piecemeal work, plan it around a shutdown or plant overhaul. Check the support beams and fasteners first; replacing grating on corroded beams only moves the problem. Service conditions by industry are covered under typical industry applications

Safety routes add their own test. Where grating on an escape route or a load-bearing platform shows a through crack or clear sag, isolate it and arrange replacement at once rather than waiting for the planned shutdown.

Records and spares

Record the installation date, product batch, resin type, colour, and the maintenance and repair history. This information serves reordering, life assessment and fault tracing.

Keep spares as a proportion of the platform area, with the proportion set by project practice; store them cool and dry, flat on bearers, out of direct sun and away from heavy loads.

Buy the next order to the same resin, colour and specification to limit colour and performance differences. If the original type is discontinued, trial a small area before committing to a full replacement.

When spares run short, reusing an old panel is common practice, but confirm its resin and capacity still suit the duty rather than checking the size alone.