Why is measuring stack pressure important in building testing?

Measuring stack pressure plays a vital role in identifying sources of air leakage within a building. When a building is subjected to testing, understanding the stack effect—the movement of air into and out of the building due to differences in indoor and outdoor air density—is essential. By measuring stack pressure, one can deduce how air is being unintentionally drawn in or expelled, which directly relates to where air leakage might be occurring.

The stack effect results in higher pressure differences at the upper levels of tall buildings, while lower levels may experience lower pressure, thereby contributing to airflow pathways that can lead to leakage. Identifying these areas is crucial for improving building performance, energy efficiency, and occupant comfort. This knowledge can then guide specific air sealing measures to mitigate leaks, enhance the building's airtightness, and ultimately contribute to better energy conservation.

In contrast, knowing about airflow adjustments, structural integrity, or energy costs, while important, is not the primary reason stack pressure is measured in the context of airtightness testing. These factors are important considerations in building design and operation but do not directly relate to the identification of air leakage sources in the same manner.