Keeping surface temperatures above the dew point helps prevent which condition on surfaces?

• A. Increases condensation on surfaces
• B. Has no effect
• C. Promotes humidity on surfaces
• D. Prevents condensation on surfaces

Answer: (D)

Dew point is the temperature at which air becomes saturated with water vapor and condensation begins on surfaces. When a surface stays warmer than the dew point, the air right at that surface cannot reach saturation, so water vapor does not condense as liquid on it. That’s why keeping surface temperatures above the dew point prevents condensation on surfaces. If the surface were cooler or equal to the dew point, condensation would occur. Humidity levels describe how much water vapor is present in the air, not whether a surface will condense moisture, so simply having humidity isn’t the condition being tested here.