: It specifically covers acid strengths between 90% and 100% by weight.

: When carbon steel contacts concentrated acid, it initially corrodes but quickly forms an insoluble sulfate layer that limits further attack.

A significant portion of NACE RP 0391 focuses on the use of carbon steel, which is the most common material for concentrated sulfuric acid storage due to its cost-effectiveness and the formation of a protective .

: This protective film is fragile. The standard recommends maintaining acid flow velocities below 0.9 m/s (3 ft/s) to prevent "velocity-accelerated corrosion" where the film is physically stripped away.