What does the neutral pressure plane refer to in a building?

The neutral pressure plane is defined as the location within a building where the air pressure is equal to the outside atmospheric pressure, meaning that the effects of stack pressure (the pressure differential caused by temperature differences between indoor and outdoor air) balance out to zero. This concept is essential in understanding how air moves through a building, particularly in relation to the effects of buoyancy that drive warm air upwards and create pressure differentials.

Recognizing this point is crucial for professionals engaged in airtightness testing because it helps in identifying where air leakage could occur and how ventilation systems might perform under different conditions. Understanding where the neutral pressure plane is located aids in determining the effectiveness of sealing measures and can influence the overall energy efficiency of a building. This concept directly ties into the overall performance of the building's envelope and informs strategies to improve airtightness.