Natural Pressure Differential – Infiltration Through Wind Results of a Long-Term Measurement

Wind pressure and thermal forces are driving forces for pressure difference on the building envelope. In European and German standards infiltration is calculated using wind speed, temperature difference and wind pressure coefficients result-ing from upstream and downstream flow on the building envelope. This long term measurements shall present measured pressure differences on the building envelope in comparison to those calculations.
Measurement of pressure differences over the building envelope over a year. Samples are a dwelling in a multi-family-house in Berlin-Friedrichshain and a dwelling in a multi-family-house on the island Helgoland. Pressure was logged for one year with capillary pipes over the gate folds of several windows. Wind speed was measured close to the building.
The recorded pressure differences show a great dependence on the wind speed and the direction of flow on the building. Pressure differences fluctuate strongly at very short intervals. A constant pressure over a certain time could not be observed. The temperature differences play a subordinate role or no role in these measurement objects.