What a warranty usually covers

An FRP grating warranty normally splits into structural performance and appearance. The structural part covers material and workmanship defects such as delamination, blistering, dry spots, exposed fibre and cracking that is not caused by external force; the appearance part covers colour and surface condition.

Structural cover commonly runs five to ten years and appearance one to three, depending on the maker's terms. A long period says little about quality on its own; the definition of failure in the clause is what matters.

A warranty is a contract term, not a property of the product. The same panel can carry completely different cover on two projects, depending on what the buyer wrote into the contract.

The usual exclusions

Chemical attack is the most common exclusion. A medium outside the selection chart, a concentration or temperature above the limit, or the wrong cleaning agent is put down to service conditions rather than a product defect.

Colour change and chalking from UV are usually classed as normal ageing, not structural failure. Once surface resin loss exposes fibre the nature of the problem changes, and the boundary has to be written into the contract.

Installation error is the other large item: cut edges left unsealed, fasteners spaced too far apart, insufficient support, over-torqued bolts, heavy items fixed directly to the grating. Failures of this kind look very much like product faults while the cause sits in the installation.

Overload, impact, fire, missed cleaning, unauthorized repair and force majeure normally sit on the exclusion list. Read every line before signing, not just the number of years.

For how resin choice sets the chemical boundary, see chemical resistance of FRP grating

UV ageing and colour difference

UV ageing works by breaking molecular chains at the resin surface, which shows as chalking, loss of gloss and paler colour. Pigments fade as well, at different rates by colour, with dark and saturated shades showing it most.

Colour change does not equal lost strength. With light chalking the structural layer is still sound, but continued resin loss exposes fibre and turns an appearance issue into a structural one, and the turning point is hard to judge by eye.

Judgement needs data: colour difference measured on a spectrophotometer, chalking grade against a reference card, surface roughness, and Barcol hardness compared with a retained sample. Photographs alone leave too much room for argument.

The contract should state the permitted colour difference, the inspection method and the inspection interval. Without them a colour complaint can only be negotiated, with neither side holding evidence.

Telling installation error from product defect

When delamination starts at a cut edge, unsealed cutting is almost certainly the cause. A cut face exposes fibre and interface, the medium creeps along it, and white marks and lifting appear within weeks to months.

Cracks radiating from a fastener hole usually mean too little edge distance or too much torque. Look for a pressure mark at the hole, a missing washer and a torque above the maker's figure, and the cause is settled.

If deflection clearly exceeds the design value, measure the support spacing first. Where the spacing is greater than the load table allows, the grating has no defect; the support condition is invalid.

Fracture surfaces help as well. A fresh break has long pulled fibres and plenty of resin on them, which points to overload; an old break shows contamination and staining, which points to long-term attack or fatigue. Keep the fracture intact when sampling.

For the correct way to cut and seal, see fabrication of FRP grating

Evidence for a claim

Photographs are the first evidence, and they need a scale, a location marker and a date. A single close-up cannot show position or extent; a wide view plus a close-up is complete.

Documents include the batch number, delivery note, invoice, warranty certificate, material certificate and test reports. The batch number matters most, because it links the site problem to a production run.

Installation records cover measured support spacing, fastener torque, photographs of cuts and sealing, the installation date and the crew. They have to be made during installation; reconstructing them afterwards convinces nobody.

Service records cover the medium, concentration, temperature, cleaning agents, load history and any abnormal event. Without them a supplier can readily attribute the failure to service outside the agreed range.

What to record at handover

The receiving inspection should record quantity, appearance, dimensions, colour and edge sealing. Photograph and notify in writing on the day a problem appears, not after installation is finished.

Installation records should cover support spacing, fixing method, torque values, cut positions and sealing material. Sealing is the step most often skipped and the one hardest to defend in a claim.

Handover documents include as-built drawings, the maintenance manual, the warranty certificate, a spare parts list and the maker's contact. The manual should state the cleaning interval and the permitted detergents.

Keep a sample from the same batch, sealed and stored. When a colour or surface dispute arises later, that sample is the only reliable reference.

For spacing and torque of fixings, see fixings for FRP grating

Writing preventive clauses

Fix the start date: delivery, completion of installation or handover. The three can differ by months, and that is where the argument usually sits.

Fix the remedy: replacement, repair or a price allowance. A clause that says the supplier will deal with it means nothing when the two sides read it differently.

Fix the response time: how many hours to attend after notice and how many days to propose a solution. A warranty with no time limit is very weak in practice.

Add the exclusion list, the method of determining cause, the third-party laboratory and who pays for it. Settling the dispute mechanism in advance works far better than arguing afterwards.

The claim process

The first step is written notice stating the time, location, symptom and extent, with photographs attached. Verbal notice is almost impossible to use as evidence later.

The second step is a joint site inspection to confirm the symptom and its extent, recorded in writing and signed. Do not dismantle or repair beforehand, because destroying the scene makes cause impossible to establish.

The third step is sampling and testing. Samples should cover both the failed area and a sound area, be numbered, sealed and signed by both sides, with the test method agreed in advance.

The fourth step is the finding and the remedy. The finding comes from a technician accepted by both sides or from a third party, and the remedy states scope, timing and acceptance criteria.

Reasonable expectations

A warranty is not insurance. It covers material and workmanship defects under normal service, not selection error, installation error or misuse.

Records made at the selection stage are worth more than the warranty clause. Write the medium, concentration, temperature, load and support conditions down and the room for later dispute shrinks.

Long life rests on three things: correct design, proper installation and timely maintenance. The warranty only covers the residual risk once those three are in place.

To push risk down further, require the load table, the immersion test report and installation training in the same contract. Documents and training prevent more failures than an extended warranty.

All of these clauses end up in product data, see the FRP grating specification guide

• State the start date and the remedy in the warranty.
• Put the exclusion list and the cause test first.
• Record torque and edge sealing during installation.
• Keep a sealed sample from the same batch.
• Notify before dismantling anything.