airflow measurement

Unintended Infiltration in buildings is responsible for a significant portion of the global housing stock energy demand. Today, the fan pressurization method, also known as blower-door test, is the most frequently used measurement method to evaluate the airtightness of buildings and determining the total air change rate of a building or a building element. However, the localization and quantification of single leaks in the building envelope remain difficult and time-consuming. In this paper, an acoustic method is introduced to estimate the leakage size of single leaks in buildings.

The characterization of power-law coefficients of the airflow through ventilation system components and ductwork or building leaks should include corrections on the airflow rate measurement because of two phenomena: a) the temperature and pressure conditions at the flow measurement device may not be the same as those seen by the test object; b) the temperature and pressure conditions experienced by the object may differ from reference conditions. This paper gives the analytical expression of these corrections depending on the air viscosity, air density and flow exponent.

Ventilation’s historical goal has been to assure sufficient air change rates in buildings from a hygienic point of view. Regarding its potential impact on energy consumption, ventilation is being reconsidered. An important challenge for low energy buildings lies in the need to master airflows through the building envelope.

The approval of the Technical Building Code has meant major changes in the construction of multi-storey buildings in Spain. One of the most important revisions, with respect to the buildings erected prior to the Technical Building Code, has been the obligation to ventilate each one of its rooms. Depending on the use and occupancy a minimum flow rate of ventilation is required in each room.