Moisture flow by vapor diffusion is governed by which law of thermodynamics?

The correct answer is the second law of thermodynamics, which relates to the principles of energy transfer, particularly in the context of entropy. This law states that energy naturally progresses from a state of order to disorder, and it describes how energy disperses or spreads out over time.

In relation to moisture flow by vapor diffusion, this law helps explain how water vapor moves from areas of higher concentration (higher energy) to areas of lower concentration (lower energy). As vapor diffuses through materials, it creates a more even distribution of moisture, increasing overall entropy. This process is vital in understanding how moisture can migrate within building envelopes and the importance of proper ventilation in preventing moisture buildup, which can lead to structural damage and health issues.

By recognizing the application of the second law of thermodynamics in vapor diffusion, one can better evaluate and address moisture-related challenges in attic spaces and other areas of a building.