Airtightness of buildings - Considerations regarding place and nature of pressure taps.
This paper discusses two particular points of the buildings airtightness measurement method (ISO 9972) in relation with the pressure difference: the nature of the pressure tap and the place of the pressure tap outside. The principle of the buildings airtightness measurement method is to measure the pressure difference induced by a given air flow rate generated by a fan. To that end, pressure measurements are made between inside and outside the building. However, with the increasing number of measurements and laboratories, more and more varied pressure taps such as pierced bottles or traffic cones are appearing. In addition, the place of the pressure tap outside largely varies; from very close to the building to very far away. Although this may seem insignificant at first glance, the nature and the place of the pressure taps play a crucial role in the measurement uncertainty. This is mainly due to the effect of wind on the building and the dynamic pressure it generates. This paper explains why it is necessary to use static pressure taps and place them away from the building and possible obstacles.