What is the minimum ventilation rate for a public bathroom with one water closet and one lavatory with a floor area of 35 square feet?

To determine the minimum ventilation rate for a public bathroom, various standards and guidelines can be consulted, including the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards.

For a bathroom equipped with one water closet and one lavatory, the minimum ventilation requirement is often set at 50 cubic feet per minute (cfm) per fixture. In this case, you have two plumbing fixtures: one water closet and one lavatory. Therefore, the calculation for the minimum ventilation rate would typically consider the combined requirements for these fixtures and any additional considerations based on the specific use of the bathroom.

The base requirement is generally 50 cfm for the water closet and potentially an additional 50 cfm for the lavatory, leading to a minimum combined ventilation rate of 100 cfm. However, because the scenario might consider different factors, such as occupancy or local regulations, the established standard commonly cited for a single-use public bathroom setup is often established at 50 cfm as the baseline for adequate ventilation.

In this context, a 50 cfm rate sufficiently accommodates the required air exchange to maintain air quality, reduce humidity, and control odors, especially in such a compact area made up of only one water closet