NACE CP2 Questions and Answers |
Latest Version | 2025/2026 | Correct &
Verified
What is the main purpose of a coating inspection?
✔✔To verify that the surface preparation and coating application meet the project specifications
and protect the metal from corrosion.
Why is surface preparation critical before applying a coating?
✔✔Because poor surface preparation can lead to adhesion failure and premature coating
deterioration.
Which factor most influences the adhesion of a coating to steel?
✔✔Surface cleanliness and profile.
What is the primary function of a primer in a coating system?
✔✔To enhance adhesion and provide initial corrosion protection.
Why is abrasive blasting commonly used on steel surfaces?
✔✔To remove rust, mill scale, and contaminants while creating a surface profile.
What does a surface profile help a coating achieve?
✔✔Better mechanical adhesion to the substrate.
1
,Which environmental condition should be checked before coating application?
✔✔Surface temperature, ambient temperature, and humidity.
Why must coatings not be applied below the dew point?
✔✔Because condensation can form on the surface, causing adhesion problems and defects.
What is the main cause of pinholes in a coating?
✔✔Trapped air or solvent escaping during curing.
Which defect is indicated by powdery residue on the coating surface?
✔✔Chalking.
Why is measuring dry film thickness important?
✔✔To ensure the coating meets the specified protection requirements.
Which tool is used to measure dry film thickness on ferrous metals?
✔✔Magnetic pull-off or magnetic induction gauge.
Why is monitoring relative humidity important during coating application?
✔✔High humidity can slow drying and promote defects like blistering or flash rust.
2
,What is the effect of flash rust on a steel surface?
✔✔It can reduce coating adhesion if not removed before coating application.
Which defect occurs when a coating sags or runs during application?
✔✔Excessive film thickness applied too quickly.
Why is it important to inspect welds before coating?
✔✔Welds may have residues, undercuts, or irregularities that affect coating adhesion.
What type of corrosion occurs uniformly across a surface?
✔✔Uniform corrosion.
Which corrosion type occurs in confined areas where oxygen is limited?
✔✔Crevice corrosion.
What causes galvanic corrosion?
✔✔The electrochemical reaction between two dissimilar metals in contact with an electrolyte.
Why is it important to remove all oil and grease before coating?
✔✔Contaminants prevent proper adhesion and may cause coating failure.
Which defect is caused by rapid solvent evaporation during application?
3
, ✔✔Cratering or fish eyes.
Why should coatings be applied within the recommended overcoating interval?
✔✔To ensure proper adhesion between coats and avoid delamination.
What is the primary purpose of an intermediate coat?
✔✔To build film thickness and enhance corrosion protection.
Which type of coating failure occurs when moisture or solvent becomes trapped?
✔✔Blistering.
Why must coatings be applied evenly?
✔✔Uneven application can cause weak points, runs, or sagging that reduce protection.
Which tool is used to inspect for holidays or pinholes in coatings?
✔✔Holiday detector or spark tester.
Why is surface cleanliness classified into different standards?
✔✔To quantify acceptable levels of contaminants for proper coating adhesion.
Which SSPC standard refers to white metal blast cleaning?
✔✔SSPC-SP 5.
4
Latest Version | 2025/2026 | Correct &
Verified
What is the main purpose of a coating inspection?
✔✔To verify that the surface preparation and coating application meet the project specifications
and protect the metal from corrosion.
Why is surface preparation critical before applying a coating?
✔✔Because poor surface preparation can lead to adhesion failure and premature coating
deterioration.
Which factor most influences the adhesion of a coating to steel?
✔✔Surface cleanliness and profile.
What is the primary function of a primer in a coating system?
✔✔To enhance adhesion and provide initial corrosion protection.
Why is abrasive blasting commonly used on steel surfaces?
✔✔To remove rust, mill scale, and contaminants while creating a surface profile.
What does a surface profile help a coating achieve?
✔✔Better mechanical adhesion to the substrate.
1
,Which environmental condition should be checked before coating application?
✔✔Surface temperature, ambient temperature, and humidity.
Why must coatings not be applied below the dew point?
✔✔Because condensation can form on the surface, causing adhesion problems and defects.
What is the main cause of pinholes in a coating?
✔✔Trapped air or solvent escaping during curing.
Which defect is indicated by powdery residue on the coating surface?
✔✔Chalking.
Why is measuring dry film thickness important?
✔✔To ensure the coating meets the specified protection requirements.
Which tool is used to measure dry film thickness on ferrous metals?
✔✔Magnetic pull-off or magnetic induction gauge.
Why is monitoring relative humidity important during coating application?
✔✔High humidity can slow drying and promote defects like blistering or flash rust.
2
,What is the effect of flash rust on a steel surface?
✔✔It can reduce coating adhesion if not removed before coating application.
Which defect occurs when a coating sags or runs during application?
✔✔Excessive film thickness applied too quickly.
Why is it important to inspect welds before coating?
✔✔Welds may have residues, undercuts, or irregularities that affect coating adhesion.
What type of corrosion occurs uniformly across a surface?
✔✔Uniform corrosion.
Which corrosion type occurs in confined areas where oxygen is limited?
✔✔Crevice corrosion.
What causes galvanic corrosion?
✔✔The electrochemical reaction between two dissimilar metals in contact with an electrolyte.
Why is it important to remove all oil and grease before coating?
✔✔Contaminants prevent proper adhesion and may cause coating failure.
Which defect is caused by rapid solvent evaporation during application?
3
, ✔✔Cratering or fish eyes.
Why should coatings be applied within the recommended overcoating interval?
✔✔To ensure proper adhesion between coats and avoid delamination.
What is the primary purpose of an intermediate coat?
✔✔To build film thickness and enhance corrosion protection.
Which type of coating failure occurs when moisture or solvent becomes trapped?
✔✔Blistering.
Why must coatings be applied evenly?
✔✔Uneven application can cause weak points, runs, or sagging that reduce protection.
Which tool is used to inspect for holidays or pinholes in coatings?
✔✔Holiday detector or spark tester.
Why is surface cleanliness classified into different standards?
✔✔To quantify acceptable levels of contaminants for proper coating adhesion.
Which SSPC standard refers to white metal blast cleaning?
✔✔SSPC-SP 5.
4
