During which conditions is it recommended to average pressure measurements on all four sides of a building?

Averaging pressure measurements on all four sides of a building is particularly recommended during windy conditions. This approach helps to account for the variations in pressure that can occur due to the wind’s effects on the building’s envelope. When wind is present, it can create localized pressure differences around the building, leading to potential inaccuracies if measurements are taken from just one or two sides. By averaging the measurements across all sides, a more reliable estimation of the overall airtightness of the building can be achieved, which is crucial for understanding the building's performance in terms of energy efficiency and air leakage.

Wind can exert different pressures depending on direction and speed, which can affect how airtight a building feels under tested conditions. Overall, the need to consider all sides ensures that the measurements reflect a comprehensive understanding of the airflow patterns around the building, which can vary significantly due to wind.

The other conditions mentioned, such as high temperatures, rainfall, and dust storms, do not have the same pronounced effect on pressure readings as wind does. Therefore, they do not require the averaging of measurements to the same extent to ensure accurate assessment during testing.