Frequently Asked Questions

What chemical resistance does Nitocote EP202 provide and are there chemicals it cannot resist?

Nitocote EP202 provides broad chemical resistance to a wide range of industrial chemicals commonly encountered in chemical plants, effluent treatment, pharmaceutical, and food processing facilities in India. Chemicals typically resisted by EP202 at the recommended DFT include: inorganic acids at moderate concentration (sulfuric acid, hydrochloric acid, nitric acid at concentrations below 30 to 40 per cent); alkalis (sodium hydroxide, potassium hydroxide at concentrations below 50 per cent); fuels (diesel, petrol, kerosene); lubricating and hydraulic oils; aliphatic solvents (white spirit, heptane, cyclohexane); and water, saltwater, and dilute aqueous solutions. Chemicals that may challenge or exceed the resistance of a standard epoxy system like EP202 include: highly concentrated strong acids above 30 to 40 per cent (particularly oxidising acids such as concentrated nitric acid and chromic acid); aromatic solvents (toluene, xylene, MEK, acetone) at high concentrations or with prolonged contact; ketones and esters at elevated temperatures; and halogenated solvents (methylene chloride, carbon tetrachloride). For industrial projects involving chemicals not in the standard tested range, a specific immersion test (submerging a cured EP202 sample in the chemical for 7 to 28 days and measuring the change in hardness, weight, and adhesion) should be carried out before specifying EP202 as the coating for the specific chemical service. Fosroc technical support or Space Arc Engineering can assist in identifying the appropriate chemical resistance test.

How many coats of Nitocote EP202 are needed for a chemical containment bund and what DFT should be specified for a battery room floor?

The number of coats and the total dry film thickness (DFT) specified for Nitocote EP202 depends on the severity of the chemical exposure and the criticality of the protection. For a chemical containment bund (a secondary containment structure designed to retain chemical spills from storage tanks or process equipment), the typical specification is two to three coats of EP202 building to a total DFT of 500 to 800 microns — this provides a robust, continuous chemical barrier film with sufficient thickness to tolerate minor pinhole or holiday defects in one coat being sealed by the subsequent coats. For a battery room floor coating where the primary chemical hazard is dilute sulfuric acid from battery electrolyte overflow or ventilation condensate, a two-coat EP202 system at 400 to 500 microns total DFT is the typical specification — supplemented by a surface coat of non-slip aggregate for the floor to be safe when wet with electrolyte. For very high-risk chemical containment (concentrated sulfuric acid storage secondary containment, chlor-alkali plant, or similar) where the chemical concentration is high and the consequences of a coating failure are severe, three to four coats of EP202 building to 800 to 1,000 microns, or alternatively a glass flake-filled epoxy system with higher barrier resistance, may be specified by the plant engineer. The DFT should be specified explicitly in the coating specification and verified by wet film thickness measurement during application and dry film thickness measurement after cure.

Can Nitocote EP202 be used as a tank lining for a concrete effluent tank in a sewage treatment plant?

Yes — Nitocote EP202 is suitable for use as an internal protective coating (tank lining) for concrete effluent tanks, equalisation tanks, biological treatment tanks, and sludge holding tanks in sewage treatment plants, providing protection against the combination of chemical attack (from hydrogen sulfide and organic acids produced by anaerobic bacterial action in sewage), mechanical erosion from sludge movement, and biological attack from bacterial and microbial action on the concrete surface. In sewage treatment and water treatment structures, uncoated concrete surfaces above the water line (in the splash zone and in the headspace above the liquid level where hydrogen sulfide gas is generated by anaerobic bacteria) are particularly vulnerable to biogenic acid corrosion — the sulfide-oxidising bacteria on the concrete surface produce sulfuric acid that attacks the cement matrix aggressively, causing rapid corrosion of the concrete surface (up to 5 to 10 mm per year in severe cases). Nitocote EP202 applied to the full interior surface of the tank (below the liquid line and above it to the headspace area) provides an impermeable barrier that prevents the biogenic acid from contacting and attacking the concrete. For the application procedure in an existing operational effluent tank: the tank must be fully emptied, cleaned by pressure washing, and allowed to dry before surface preparation and EP202 application. All cracks and defects in the concrete must be repaired with Renderoc repair mortar before coating. For new effluent tanks, EP202 is applied after the concrete has cured for 28 days and the substrate has dried to within the moisture threshold.