The so-called blower door test is a differential pressure method according to DIN EN ISO 9972 and represents an important and now well-established, quality-assuring investigation to check the airtightness of a building and to locate leaks of individual components or connections. It is carried out by qualified and approved experts before the completion of a building, also so that the detected leaks can be repaired in the course of the construction project, or in order to be able to confirm airtightness requirements, which result, for example, from the thermal insulation certificate.
In order to make the airtightness measurable, an artificial overpressure and negative pressure of at least 50 Pa is generated in the building with the help of a blower. To do this, all visible and known openings such as windows, doors, ventilation outlets, etc. are closed or provisionally sealed beforehand. The speed at which the pressure difference is reduced can be used to calculate a factor for the degree of airtightness. To locate the leaks, the mere scanning can provide information, or additional technical aids such as a thermo-anemometer, an infrared camera or a fog generator are used.
Source: bauwion
