How long does a GRP delineator post last?
Short answer
There are two separate lives and they should not be confused. The stated reflective performance period for this product is 60 months. The manufacturer states a 20-year body life under normal weather conditions. Assess the scope and conditions alongside the product documents and written warranty.
The technical specification asks for a raw-material supplier document that reflective performance holds for 60 months; the mechanical commitment for the body is a separate document, and the two are not mixed. That is a floor rather than a target. In practice three things decide the life: resin quality, UV resistance and where the colour sits.
On a painted post the first scratch opens the colour and the first summer starts the fading. In a GRP post that carries pigment in the compound, a scratch marks the surface without changing the colour. Production keeps the yellowness index at or below 12 to ASTM E313.
What usually shortens the life is installation rather than material. Driven too shallow, a post loosens a little at every strike and stands crooked by the end of one winter. The burial depth arrives marked as a black line on the body: that line is ground level.
Three things decide the life: sun, impact and installation. Sun fades the surface, impact tires the body, and a wrong installation lifts the post out after the first winter. Of the three, installation is the easiest to control.
The body and the reflector do not last the same time. The retroreflective material usually tires first, and replacing the reflector on a sound body costs markedly less than buying a new post.
Set inspection intervals to the authority’s maintenance plan and site conditions. Check the body for cracks, the post’s position and ground retention, and reflector visibility at night; inspect again after an impact.
Replacing a whole route at once costs less than replacing posts one by one. The crew makes a single trip, the material comes from one batch, and colour and brightness match along the route. A route renewed piecemeal looks patchy within a few years.
The specification carries the conditions that decide the life rather than the life itself. Given sun load, impact frequency and ground type a supplier can state a realistic expectation. Asking only for a number of years asks for a figure nobody can hold.
The commonest mistake is assuming concrete is cheap and choosing the post in concrete. A concrete post costs more than GRP both as a product and to install; on top of that it breaks at the first impact, damaging itself and the vehicle. Replacement costs widen the gap further.
The question for a supplier is the spare parts policy. A post whose reflector is sold separately can be renewed while the body is sound. One sold only complete is replaced entirely for a small amount of wear.
Keeping records extends the life. Where it is written which section was equipped when, renewal is planned in batches and the crew makes one trip. On a route without records every renewal becomes a separate survey job.
An expected life is not a warranty text: it depends on site conditions and is not committed as a single number. The warranty supplied with the product is shared separately in writing.
