Newbuild and industrial tenders increasingly ask for 25 years to first major maintenance. What that shift changes in system selection, film build and shop-floor practice.
Ask ten shipyards and industrial fabricators what has changed in coating specifications over the past few years and the same answer comes back: the target service life has moved up. Where a 15-year system to first major maintenance was once the standard ask, 25 years is now a routine requirement in newbuild tenders, offshore projects and long-life infrastructure. The coating package is no longer treated as a cost to be minimised; it is treated as an asset-life decision.
Where the pressure comes from
- Drydock and downtime costs. For a vessel or a plant, taking the asset out of service now costs far more than the paint itself. Owners are buying fewer, longer intervals rather than cheap short ones.
- Access is the real constraint. In the splash zone, on a tank floor or under a deck, re-coating later costs many times what it costs to do it properly the first time.
- Tenders reward predictability. A specified system with a documented standard, published thicknesses and traceable inspection gives the owner something a low bid cannot: a forecast.
What changes in the coating system
- Total dry film thickness rises. Longer life is bought partly in film build, and the increase usually lands on the primer and the intermediate coat, not on the topcoat.
- The primer family becomes less negotiable. In C5-M and CX exposure a zinc-based primer is written into most long-life system tables; zinc silicate or a two-coat zinc-rich build appears where 25+ years is targeted.
- Intermediate coats do more work. MIO-bearing epoxies and high-build epoxies are specified for barrier performance and edge retention, not merely to add thickness.
- Compatibility is checked as a system. Primer, intermediate and topcoat are qualified together, with recoat windows verified against the actual shop schedule rather than the theoretical value.
What it means on the shop floor
- Surface preparation grade and profile depth are inspected and recorded instead of assumed; the standard and the blast grade increasingly appear in the specification itself.
- Stripe coats on welds, edges and cut-outs move from best practice to a hold point.
- Environmental limits — steel temperature above dew point, relative humidity, and the permitted recoat window — become contractual rather than advisory.
- Uncertainty is pushed upstream. Yards that cannot guarantee a preparation standard tend to specify a more tolerant primer family instead of gambling on the aggressive one.
The practical takeaway
A longer service life does not automatically mean the most expensive product on the list. It means the system has to be matched to the exposure, the achievable surface preparation and the real construction schedule. Whether the specification names a particular brand or stays generic, the questions are the same: what is the corrosivity category, what is the target life, what preparation can actually be delivered, and does the chosen primer-intermediate-topcoat combination close those gaps? Product data from publicly available manufacturer materials provides the starting numbers; site conditions decide whether they hold. Specific parameters are always governed by the latest version of the manufacturer's technical data sheet (TDS).