Compressed breathing air shall meet at least Grade _ breathing air.

Compressed breathing air shall meet at least Grade _ breathing air.

• A. Grade A
• B. Grade B
• C. Grade C
• D. Grade D

Answer: (D)

Compressed breathing air is classified by quality levels, with Grade D serving as the baseline standard for air that is safe to breathe in most workplace respiratory systems. This grade ensures the air has minimal contaminants—such as hydrocarbons, carbon monoxide, and hydrogen sulfide—and is free of noticeable odor, making it suitable for use in atmosphere-supplying respirators. Higher grades exist for more stringent environments, but the minimum requirement is that the air meets Grade D or better. So the air must be at least Grade D.

Compressed breathing air is classified by quality levels, with Grade D serving as the baseline standard for air that is safe to breathe in most workplace respiratory systems. This grade ensures the air has minimal contaminants—such as hydrocarbons, carbon monoxide, and hydrogen sulfide—and is free of noticeable odor, making it suitable for use in atmosphere-supplying respirators. Higher grades exist for more stringent environments, but the minimum requirement is that the air meets Grade D or better. So the air must be at least Grade D.