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Purpose of the work
The overall buildings leakage results from the sum of the individual contribution of its components. Quantifying this contribution would be of major importance for building designers that intend to improve building enclosures for airtightness optimization. Typically, building components airtightness is tested in laboratory but several examples of a different in-situ performance are reported in the literature. Therefore, this work aims at assessing the air permeability of several building components using in-situ blower door tests.
Method of approach
The most common procedure to measure the air leakages through a building envelope is the fan pressurization method, commonly called the blower door test. To quantify the components permeability a methodology based on the successive sealing of the building components can be used. The consecutive differences between tests allow for the evaluation of the component’s individual contribution to the overall leakage of the room.
Content of the contribution
In this contribution, an initial discussion based on an extensive literature review regarding the experimental techniques for assessing the components permeability is presented. The experimental methodology is explained and the results of several experimental campaigns are presented and discussed.
Results and assessment of their significance
The results of several experimental campaigns allowed for the permeability quantification of some building components: enclosure, windows, roller-shutter box, connection of the steel columns with the floor and ventilation ridge. An enclosure sample, including wall panel and one window, was built in the laboratory and air permeability tests were also performed. Moreover, due to its importance, a large experimental campaign for assessing windows permeability was carried out. A total 23 windows were tested. The results uncertainty was estimated following the procedure indicated in ISO 9972. Connected infrared thermography of the building elements is also presented.
Conclusions
The airtightness of a building can be tested using a blower door and the components permeability can be estimated using different set-ups with a consecutive sealing of the elements. However, using these results to estimate buildings n50 is still complicated since a complete database regarding the components permeability is still missing. The results of the experimental campaign to assess windows airtightness revealed that: the average window contribution for the room permeability was 15 % and the roller-shutter was 44 %; no window reached the maximum class according to EN 12207 standard and only one achieved class 3, using the air permeability at 50 Pa as indicator; the year of construction, the frame material and the opening system were identified as the key parameters for the windows airtightness. Moreover, the uncertainty of the results is affected by the relative importance of the tested window permeability compared to the overall room enclosure permeability. The uncertainty can however be used to determine the upper and lower limits of the component contribution to airtightness.
Note
For more information, please contact the reference author at: nuno.ramos@fe.up.pt