Indoor Air sciences CSMI Practice Exam

A building in a hot and humid climate should be operated under which condition?

1. Under equilibrium

2. Under a positive pressure

3. Under a neutral pressure

4. Under a negative pressure

The correct answer is: Under a positive pressure

In a hot and humid climate, operating a building under positive pressure is essential to control moisture and maintain indoor air quality. Positive pressure helps to prevent the infiltration of warm, humid outdoor air, which can lead to higher indoor humidity levels and potential mold growth. This operating condition forces conditioned air out of the building and minimizes the entry of unconditioned air through gaps, cracks, and openings in the building envelope. Maintaining positive pressure can lead to better temperature regulation by keeping the indoor environment cooler and more comfortable, as it reduces the likelihood of warm air entering. This is particularly important in climates where humidity can accelerate issues like dampness and the resultant health risks associated with poor air quality. Positive pressure also ensures that any pollutants that might be generated indoors, such as volatile organic compounds (VOCs) from building materials, are effectively diluted and vented outside. In contrast, neutral or negative pressure could allow warm, humid air to enter the space, compromising indoor conditions and increasing the burden on mechanical cooling systems. While equilibrium is important in various contexts, the risks associated with moisture management in hot and humid climates make positive pressure the preferred choice.