Every year, corrosion, erosion, and chemical degradation force unplanned shutdowns across Indian and Southeast Asian process plants. The cost is not just the downtime — it is the emergency procurement, the accelerated equipment replacement, and the safety incidents that follow when protective systems are ignored or wrongly specified.
Choosing the right industrial coating systems is not a procurement checkbox. It is an engineering decision that determines whether your FGD absorber runs for eight years or two, whether your condenser tubes need replacement in five years or can be refurbished for fifteen, and whether your coal bunker requires constant patching or stays operational through an entire maintenance cycle.
Why Generic Epoxy Coatings Fail in Process Environments
The most common mistake in industrial coating specification is treating all epoxy coatings as equivalent. A standard epoxy paint used in construction has fundamentally different chemistry from a 100% solid, high-build novolac epoxy engineered for continuous immersion in sulphuric acid.
Standard epoxy coatings contain solvents, which means they shrink as they cure, creating micro-porosity. In a chemical tank or FGD absorber, that micro-porosity becomes a pathway for acid ingress within months. By contrast, a 100% solids system has zero volatile organic compounds (VOC), cures without shrinkage, and forms a fully dense barrier with no internal voids.
For plant engineers, the specification question is not “epoxy or not” — it is which epoxy chemistry, at what build thickness, applied to what surface preparation standard, in what environment.
Four Factors That Define the Right Industrial Coating Systems
Every industrial coating decision comes down to four variables. Get all four right and the coating performs. Ignore any one of these, and you’re putting your business at risk.
1. The Corrosion Mechanism
Is the equipment failing due to electrochemical corrosion (oxygen + moisture + metal), chemical corrosion (acid or alkali immersion), erosion-corrosion (abrasive particle impact at velocity), or a combination? Each mechanism requires a different coating response.
A condenser water box corroding due to galvanic interaction between dissimilar metals needs a different solution than a coal mill duct failing because abrasive fly-ash is eroding the steel at high velocity. Specifying the wrong chemistry for the mechanism delivers the same result as specifying nothing at all.
2. The Operating Temperature
Most standard epoxy systems are rated to 60–80°C for continuous service. In FGD systems, chimney liners, and heat exchanger surfaces, operating temperatures can reach 120–150°C. A coating not rated for the operating temperature will blister, delaminate, and fail within months.
Always confirm both the continuous operating temperature and any thermal shock cycles the surface will experience. Equipment that regularly heats and cools imposes mechanical stress on the coating film that can cause adhesion failure even within rated temperature limits.
3. The Chemical Environment
Industrial coatings are not universally chemical-resistant. A standard bisphenol-A epoxy performs well against water, mild alkalis, and many hydrocarbons, but it will fail in continuous strong acid service. For concentrated sulphuric acid, hydrochloric acid, or solvent environments, a novolac epoxy — which uses a denser, more tightly cross-linked polymer network — is required.
For mixed environments, ceramic-filled or tile-based systems provide the necessary combination of chemical inertness and surface hardness.
4. The Substrate and Surface Condition
The strongest coating system in the world will fail if applied to inadequately prepared steel. For protective coatings in immersion or chemical service, steel substrates require blast cleaning to Sa 2.5 or Sa 3 standard (ISO 8501-1) with a defined anchor profile. Applying a high-performance coating over mill scale, rust, or surface contamination reduces adhesion strength by up to 70%.
Matching Industrial Coating Systems to Industrial Applications
The following is a direct-specification guide for the most common high-risk applications in Indian and Southeast Asian process industries.
FGD Absorbers and Ducting (Power Plants)
The operating environment inside an FGD absorber is among the most aggressive in any process industry: pH levels between 0 and 2, continuous wet scrubbing, abrasive fly-ash slurry, and temperatures ranging from 50–90°C. Standard linings fail within 12–18 months.
The correct specification is a 100% solids novolac epoxy system with a ceramic aggregate filler, applied at 3–5 mm total build thickness over Sa 2.5 blast-cleaned steel. Duromar coating systems are engineered specifically for this environment and have demonstrated service lives of 8–12 years in FGD applications.
Condenser Tubes and Water Boxes (Power and Desalination Plants)
Condenser tube corrosion is one of the leading causes of forced outages in thermal power plants. Once tubes begin leaking, contamination of the steam circuit follows, leading to boiler damage and extended outages. Full tube replacement is expensive and time-consuming.
The Plastocor® tube-lining system addresses this without tube replacement. The system involves hydro-jetting the tube interior, applying a controlled-thickness epoxy lining via a through-tube applicator, and curing in situ. The result is a restored tube with corrosion protection rated to 15 years.
Coal Bunkers, Silos, and Hoppers
The problem in coal storage is not chemical — it is mechanical. Coal is abrasive, and the impact and sliding loads on the internal surfaces of a steel or concrete bunker create surface wear that leads to structural thinning and, eventually, breakthrough. An equally serious problem is coal hang-up: sticky or fine coal adhering to bunker walls and disrupting consistent coal flow to the mills.
The Duromar® EAC and EAC-LV systems solve both problems. The ceramic-filled, anti-stick epoxy lining provides abrasion resistance combined with a low-friction surface that prevents coal adhesion. Applied at 3–6 mm thickness, the system reduces coal hang-up incidents, improves coal flow consistency, and protects the structural steel from ongoing wear.
Chemical and Acid Storage Tanks
Tanks storing sulphuric acid, hydrochloric acid, caustic soda, or process chemicals require internal linings with verified chemical resistance, not just general-purpose epoxy. The correct approach involves chemical immersion testing data from the coating manufacturer for the specific chemical, concentration, and temperature in your application.
Duromar® novolac epoxy systems provide resistance to a broad range of chemicals in continuous immersion service, including pH 0–14 environments. Thickness requirements vary by chemical aggressiveness, from 2 mm for mild chemical service to 6 mm for concentrated strong acid environments.
Pump Impellers and Wet-End Components
Pump impellers operating in slurry, sea water, or process fluid service are subject to combined erosion and corrosion that standard metallurgical approaches cannot fully address. Ceramic-filled epoxy coatings applied to impeller surfaces reduce the rate of material loss, restore worn geometry, and provide a chemically resistant barrier.
The key specification requirement for pump protection is adhesion strength — the coating must bond to the curved, profiled surface geometry of the impeller without edge thinning or disbondment under centrifugal loads.
What Proper Coating Application Looks Like
Specifying the right coating system is half the job. The other half is application quality. A correctly specified coating, badly applied, fails just as quickly as the wrong coating.
The application process for industrial protective coatings in critical service follows a defined sequence:
Surface preparation is always the first and most critical step. For steel in immersion or chemical service, this means abrasive blast cleaning to the specified standard, followed by application within the maximum re-rust time. Any delay between blasting and coating requires re-blasting.
Environmental control is essential. High humidity causes moisture condensation on blast-cleaned steel surfaces and interferes with epoxy cure. Professional coating contractors use dehumidification equipment to maintain relative humidity below 85% and ensure the surface temperature is at least 3°C above the dew point throughout application and initial cure.
Application method and thickness control determines whether the specified build is achieved uniformly. Plural-component spray equipment is required for high-viscosity, fast-reacting 100% solids systems. Film thickness must be measured at multiple points per square metre using calibrated wet and dry film thickness gauges, with results documented.
Holiday testing (spark or low-voltage wet-sponge testing depending on thickness) verifies continuity of the applied film and identifies any pinholes or gaps before the system is put into service.
Without these four controls in place, no coating system, regardless of its chemistry, will perform to its rated service life.
Working with a Qualified Coating Applicator
The coating manufacturer’s product data sheet is a starting point, not a complete specification. A qualified industrial coating applicator brings the engineering knowledge to match the product to the environment, write a project-specific application procedure, manage surface preparation quality, control the application environment, and document thickness and continuity testing results.
For critical applications — FGD linings, chemical tank internal coatings, condenser tube protection — the applicator should hold relevant certifications (NACE, ISO 9001), have verifiable reference projects in the same application category, and be able to provide application procedure documents and inspection test plans before project commencement.
Arudra Coatings operates as the authorised applicator for Duromar® and Plastocor® systems across India and Southeast Asia, with NACE-certified engineers and over 20 years of field application experience in power, petrochemical, marine, and desalination projects.
Choosing the right industrial coating systems is essential for ensuring long-term equipment protection, reducing downtime, and improving operational efficiency. Partnering with experienced applicators ensures the system performs as intended.
For coating system recommendations specific to your application, contact us at info@arudra.co or call 044-24901623.
FAQ’s
1. What is an industrial coating system?
An industrial coating system is a protective layer applied to equipment and structures to prevent corrosion, chemical attack, and physical wear.
2. Which coating is best for chemical storage tanks?
Novolac epoxy coatings are best for chemical tanks — they resist concentrated acids, alkalis, and solvents in continuous immersion service.
3. How long do industrial coatings last?
A correctly specified and applied industrial coating lasts 8–15 years. Poor specification or application can reduce this to under 2 years.
4. What surface preparation is needed for industrial coatings?
Steel surfaces must be blast cleaned to Sa 2.5 or Sa 3 standard before coating. Poor preparation is the leading cause of early coating failure.
5. Why do epoxy coatings fail in process plants?
Epoxy coatings fail when the wrong type is specified for the environment — standard epoxy cannot handle strong acids, high temperatures, or abrasive conditions.
6. How do you choose the right industrial coating systems?
Choose industrial coating systems based on the operating environment, temperature, chemical exposure, and type of surface. Selecting the right coating ensures durability, corrosion resistance, and long-term equipment protection.
