What is the ventilation rate for O2 without dump for active occupants?

The ventilation rate for oxygen (O2) without dump for active occupants is established at 25 air changes per minute (acfm). This standard is based on the understanding of how active individuals consume oxygen and produce carbon dioxide during their efforts, necessitating a significant airflow to maintain safe and breathable conditions in a diving environment.

Active occupants, such as divers engaging in physical tasks, require a higher ventilation rate to compensate for increased metabolic activity, which elevates oxygen consumption and carbon dioxide production. The 25 acfm rate ensures that there is an adequate exchange of air to support these physiological needs effectively, thereby preventing hypoxia and maintaining a safe environment.

In contrast, lower ventilation rates would not sufficiently support active occupants, leading to potential safety hazards due to insufficient oxygen levels and the accumulation of carbon dioxide. Thus, the established rate serves as a crucial guideline in managing air quality during underwater operations.