BlowerDoor

The need for airtightness control is a reality given its impact on buildings’ energy use and IAQ. For the past few years, this fact has resulted in energy performance regulations being established in many countries in Europe and North America. However, compliance proof is not always required, and on-site testing is often avoided. In this sense, predictive models have become useful in the decision-making process and to estimate input values in energy performance simulation tools.

This study sets out to investigate to what extent the air permeability of a building envelope of a dwelling remains constant over longer periods of time. This was evaluated by executing an air pressurisation test in 30 dwellings located in Belgium and comparing these results to the initial measurement results obtained shortly after the construction of the buildings. The time span between both measurements ranges from 293 days to 4045 days. On average, the air infiltration rate of the building envelope increased with 24%, i.e. an increase of 64 m³/h at a 50 Pa pressure difference.

Purpose of the work

To expand the use of BlowerDoor and thermal equipment combined with Radon

Method of approach

When building is set on very low negative pressure, use the Radon sniff-equipment called RAD7 to count radon at places where thermal imaging camera tell there is draft that can be assumed tob e leaks from the ground. If the found leakages are from the ground it often show higher level of Thoron, Radon and Polonium values, than the measurements elsewhere in the room.

Conclusions

The trend in European countries, such as Belgium, France and Germany is that the quality of the airtightness of the building envelope is getting better and better. This is true for small, airtight apartments, Passive houses and some large buildings with an excellent airtightness due to special requirements, e.g. oxygen reduction or fire protection.

In this paper we present a series of leakage tests on extremely airtight dwellings (ACH50 < 0.6 upon completion) in which the durability of the airtightness and the measurement uncertainty involved are assessed. In literature, repeatability and reproducibility issues have been discussed by several authors, along with influences of weather. It remains unclear, however, to what extent the available uncertainty intervals are relative or absolute.

Through the experiences gained by building a sufficient number of air-tight buildings, the author will illustrate the ease of detailing and constructing an air tight building. Using parallels to conventional building typologies, the methods of making an air-tight building enveloppe will be explained. The presentation will be divided into following chapters:

1. Precicious building methodology. 

Most dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems. Consequently, quantification of envelope air-tightness is critical to determining how much energy is being lost through infiltration and how much infiltration is contributing toward ventilation requirements. Envelope air tightness and air leakage can be determined from fan pressurization measurements with a blower door. Tens of thousands of unique fan pressurization measurements have been made of U.S.