What is the minimum exhaust rate required for an exhaust fan in a public bathroom with intermittent operation?

The minimum exhaust rate required for an exhaust fan in a public bathroom with intermittent operation is established to effectively maintain indoor air quality and user comfort. The correct choice indicates that 70 cubic feet per minute (cfm) is the necessary rate to adequately remove odors, moisture, and contaminants in such spaces.

Public bathrooms experience fluctuating use patterns, leading to varying levels of generated pollutants and humidity. An exhaust rate of 70 cfm is designed to tackle the high demand created during peak usage times. This ensures that air is continually refreshed, which is crucial for minimizing moisture buildup that can lead to issues like mold and mildew, as well as for controlling odors that can be problematic in public settings.

In settings where higher volumes of air need to be cycled out rapidly to maintain sanitary conditions, this requirement is key. Lower rates would not sufficiently address the concerns present in these environments, contributing to an uncomfortable or unhygienic atmosphere. Thus, the selection of 70 cfm aligns with best practices to ensure air quality and comfort in public restrooms.