FUSION Issue 3-2026 DIGITAL - Flipbook - Page 22
COATINGS
COATING FOR
THE LONG GAME
As service life
expectations push
beyond twenty-five
years, the way coatings
are specified, applied,
and maintained needs
to change.
A coating is, at its most basic, a
sacrifice layer. It sits between a
structure and the environment,
absorbing what the environment
throws at it so that the substrate
underneath does not have to. In
a mild environment, a modest
coating will do a reasonable job
for a reasonable number of years.
In a harsh one, think saltwater, UV
exposure, thermal cycling, and
chemical attack, the demands are
of a different order entirely.
The marine and aerospace
industries have always understood
this. But the expectations placed
on coatings in both sectors are
shifting significantly. Where a ten
to fifteen year service life was
once considered acceptable for a
well-specified protective system,
operators and asset owners are
increasingly asking for twentyfive years and beyond. Some
programmes are now targeting the
life of the structure itself.
That is not simply a product
specification change. It is a
fundamental shift in how the
entire coating process needs to
be approached, from substrate
preparation through application to
long-term maintenance.
Why the bar is rising
Several pressures are
converging to drive longer
service life expectations.
In the marine sector, the
economics of dry-docking have
become increasingly difficult to
justify at short intervals. Taking
a commercial vessel or offshore
asset out of service for recoating is
expensive in its own right; the lost
operational time compounds that
cost significantly. Operators who
can extend the intervals between
major maintenance events gain a
meaningful commercial advantage,
and the appetite for coating
systems that genuinely support
this is real and growing.
Offshore wind is a particular
pressure point. The expansion of
offshore wind installation over
the past decade has created an
enormous inventory of steel
and composite structures in
some of the harshest corrosion
environments on the planet.
Turbine foundations, towers, and
21
transition pieces designed for a
twenty-five-year operational life
need coating systems capable of
protecting them across that entire
span, ideally without requiring costly
maintenance access in a logistically
complex offshore setting.
In aerospace, the drivers are slightly
different but the direction is the
same. Aircraft operating cycles
are longer. Airframe lifespans
are extending. Coating systems
that degrade or lose adhesion
before the aircraft reaches its
structural inspection interval
create maintenance burdens that
operators want to avoid.
What a long-life
system actually
requires
Specifying a coating for a
twenty-five-year service life is
not simply a matter of choosing
a higher-performance product
and applying it in the same way as
everything else. The system
approach, meaning the
combination of surface
preparation, primer, intermediate
coat, and topcoat, needs to
be designed holistically for the
exposure environment.
Under ISO 12944, the international
standard for corrosion protection
of steel structures, marine
environments sit at the severe end
of the classification scale. In practical
terms, this means every element
of the coating system needs to be
specified for the actual conditions
the structure will face: layer thickness,
zinc loading in the primer, topcoat
chemistry. A twenty-five-year system
typically costs twenty to thirty per
cent more upfront than a shorter-life
alternative, but lifecycle economics
almost invariably favour the more
durable option once recoating
intervals and operational downtime
are factored in.
Surface preparation is the element
most frequently underestimated.
Coating performance over long
service lives is disproportionately
dependent on the quality of
the substrate when the coating
is first applied. Contamination
from salt, oil, or moisture
compromises adhesion in ways
that become apparent not
immediately, but years later
when the system is already deep
into its intended service life
and rectification is expensive. In
marine environments, achieving
and maintaining the specified
surface cleanliness and profile
before application is a genuine
operational discipline, not a
procedural formality.
Application as a
discipline
Beyond product selection
and surface preparation, the
application process itself becomes
critical when the target is a multidecade service life.
Dry film thickness consistency
matters enormously. Underapplication at any stage
reduces the protective barrier
