THE WHOLE PLANT IMPERATIVE • PART 8
The lowest-priority work on the plant, carrying the steepest cost curve on the plant. Those two facts are related.
Corrosion is the only failure mode on a power plant that never stops working. It doesn’t need the unit online. It doesn’t pause during an outage, a mild summer, or a capital freeze. It runs continuously, at a rate set by the coating you last applied and the moisture you last let in, and it is entirely indifferent to your maintenance schedule.
It is also, by a wide margin, the easiest work on the plant to postpone. Nothing about a coating system trends toward a limit. There is no analyzer, no permit, no availability number that moves. The whole judgment is visual, and visual judgment is exactly what loses to a schedule.
The steepest curve on the plant
Structural deterioration is the only degradation in this series that gets meaningfully more expensive the longer you look away — not linearly, but by orders of magnitude.
Surface corrosion caught early is a cleaning and recoating job in the range of $5,000 to $15,000. Left alone, it works into the substrate, and the same location becomes section loss requiring plate replacement, engineered repair, scaffolding, and outage time — $200,000 to $500,000 and up. That is a 20 to 50 times escalation on the identical defect, and the only variable that moved was time.
No other system in this series behaves that way. A fouled condenser costs about the same to clean whenever you get to it. A catalyst costs what a catalyst costs. Structure is the one place where the deferral itself is the expense.
There is a scheduling reality worth naming here, because it changes the arithmetic. Coatings work is widely assumed to require the unit down, which pushes it into outage windows that are already oversubscribed — and it loses that competition every time, to work that is scoped and funded. But a significant amount of it doesn’t require an outage at all. HRSG casings, among others, can largely be coated with the units in service. Work that can be done online is not competing for outage hours, which means the usual reason for deferring it doesn’t apply.
Nothing on the plant gets cheaper by waiting. This is the one that gets 20 times more expensive.
Insulation has three jobs and fails at all of them quietly
Insulation is treated as thermal efficiency, which is one of the three things it does. It also keeps surface temperatures inside the range that makes the plant safe to walk, and it keeps moisture off steel that would otherwise corrode.
Degraded or missing insulation shows up first as heat loss you pay for continuously and never see itemized. It shows up second as a personnel exposure on equipment people work around every day. And it shows up third, and worst, as corrosion under insulation — the failure mode that has damaged the piping while looking completely intact from the outside.
CUI is the purest example of this series’ argument. Water enters through damaged jacketing or a failed vapor barrier, sits against the pipe, and corrodes it inside a system built to hold heat in. The insulation that hides the damage is the same insulation that caused it. Nothing about the exterior indicates a problem until someone opens it or the pipe fails, and the locations most at risk are entirely predictable: penetrations, terminations, supports, anywhere jacketing has been disturbed for other work and reinstalled by whoever was closest.
Look at what nobody is looking at
The disciplines here are ordinary and that is the point. Infrared thermography walk-downs find wet and missing insulation across a plant in a fraction of the time a manual survey takes, and can be done with the unit running. Documented coating condition surveys on a set schedule turn a visual judgment into a trend somebody can defend in a budget conversation. Pipe support inspection — hangers, spring cans, guides — catches the load path problems that quietly transfer stress into equipment that was never meant to carry it.
There is a capability question underneath all of this that plants are running into more often. Specifying the right coating system for a specific service environment is technical work, and the people who carried that expertise in-house are retiring faster than they are being replaced. A surprising number of plants now have thorough inspection programs and no confident answer about what to actually apply.
None of this work will ever win an argument on urgency, because urgency is exactly what it doesn’t have. It wins on arithmetic. Every year it slides, the same defect gets more expensive to fix, and the plant that intends to run to 2065 is making that trade roughly forty more times.
Next in the series: the numbers behind all of it — what whole-plant maintenance actually returns, and how to make the case to the people holding the budget.
For more information on how Groome can help make a difference, visit our Gas Turbine Plant Performance Solutions page.
Start from the beginning → YOUR TURBINE IS FINE. THE ASSETS AROUND IT MAY NOT BE.
