Which description best describes Stage 1 corrosion condition?

• A. Metal sound. Light rust or flash rust. (Bubbling of paint)
• B. Metal sound. Heavy Rust with and/or light pitting
• C. Metal unsound. Heavier rust and pitting. (Scaling)
• D. Metal unsound. Extensive rust and heavy pitting with holes in metal throughout.

Answer: (A)

Stage 1 corrosion is the earliest, least severe form of deterioration, where the metal beneath the coating is still sound and the damage is mainly on the surface. The best description shows the metal still sounding solid, with only light rust or flash rust appearing on the surface, and any paint bubbling indicates the coating is beginning to blister from corrosion beneath it—not that the metal itself has begun to fail. This combination—surface-only rust with intact metal—fits Stage 1.

The other descriptions reflect progressively worse conditions: heavier rust with some pitting, or scaling and a visibly unsound metal, or extensive rust with holes. Those signs show deeper damage and structural compromise, which are beyond Stage 1.