What is the maximum allowable dew point for mechanically or indirectly evaporatively cooled buildings?

What is the maximum allowable dew point for mechanically or indirectly evaporatively cooled buildings?

• A. Maximum 70°F dew point.
• B. Maximum 75°F dew point.
• C. Maximum 60°F dew point.
• D. No dew point limit.

Answer: (C)

Dew point controls moisture condensation risks in cooled spaces. In mechanically or indirectly evaporatively cooled buildings, keeping the supply air’s dew point low helps prevent water from condensing on cooling coils, ductwork, and cold surfaces, which can lead to condensation, material damage, and mold growth. Setting a maximum dew point of 60°F provides a practical margin to maintain comfortable indoor humidity levels while avoiding condensation under typical room temperatures. Choosing a higher dew point, like 70°F or 75°F, would mean more moisture in the supplied air, increasing the chance of condensation and humidity-related problems. There isn’t a dew point limit would not set any moisture control, which would also be problematic. Thus, 60°F is the appropriate limit.

Dew point controls moisture condensation risks in cooled spaces. In mechanically or indirectly evaporatively cooled buildings, keeping the supply air’s dew point low helps prevent water from condensing on cooling coils, ductwork, and cold surfaces, which can lead to condensation, material damage, and mold growth. Setting a maximum dew point of 60°F provides a practical margin to maintain comfortable indoor humidity levels while avoiding condensation under typical room temperatures.

Choosing a higher dew point, like 70°F or 75°F, would mean more moisture in the supplied air, increasing the chance of condensation and humidity-related problems. There isn’t a dew point limit would not set any moisture control, which would also be problematic. Thus, 60°F is the appropriate limit.