When using an anemometer, what is the recommended distance to be from the building while measuring wind speed?

When measuring wind speed with an anemometer, it is crucial to maintain an appropriate distance from the building to ensure that the readings accurately reflect the ambient wind conditions, free from potential obstructions or influences created by the building itself. The recommended distance of 30 feet allows the anemometer to measure wind speed in a more representative area that is less affected by the building's surface and geometry. This distance helps minimize turbulence and provides a clearer understanding of how wind interacts with the structure, which is essential for evaluating the building’s performance in airtightness testing.

In contrast, distances that are either too close would risk capturing distorted readings impacted by the structure, while moving too far away could lead to measurements that might not accurately reflect the wind conditions affecting the building itself. Thus, 30 feet strikes a balance, ensuring the data collected is relevant and useful for assessing the overall airtightness of the building during testing.