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Airtightness

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Thoroskar Relander – 1st expert on this subject based on the ideXlab platform

  • Airtightness estimation a state of the art review and an en route upper limit evaluation principle to increase the chances that wood frame houses with a vapour and wind barrier comply with the Airtightness requirements
    Energy and Buildings, 2012
    Co-Authors: Thoroskar Relander, Sverre Holos, Jan Vincent Thue

    Abstract:

    Abstract High Airtightness is particularly important in order to achieve energy efficient buildings. Of this reason Airtightness estimation is of interest. Over the past 30 years researchers have worked on Airtightness estimation. This article is divided into two parts. The 1st part deals with earlier work on Airtightness estimation. It is seen that there are relatively few references in the literature that deal with estimation of Airtightness. None of the reviewed references argue that Airtightness measurements can be replaced by estimates. The only reference that deals with Airtightness estimation of wood-frame houses with high Airtightness did not manage to find a correlation between the estimated and the measured Airtightness. For a contractor what really matters is not an estimate of the Airtightness of the finished building, but a reliable means to be sure of reaching the Airtightness requirement. It is therefore customary to perform blower-door tests stepwise during the construction process. First the Airtightness of the building with the wind-barrier is measured, n 50w . Then the Airtightness of the finished building that also has a vapour barrier is measured, n 50f . The Airtightness requirement is set for n 50f . Of various reasons it is not given that n 50f n 50w for a given building, and consequently one should have an idea of what an upper limit of n 50w should be in order to be confident to reach the n 50f requirement. In the 2nd part of the article it will be shown how this upper limit of n 50w can be found by statistical analysis based on systematic measurements of n 50w and n 50f as part of a quality assurance system.

  • Airtightness estimation—A state of the art review and an en route upper limit evaluation principle to increase the chances that wood-frame houses with a vapour- and wind-barrier comply with the Airtightness requirements
    Energy and Buildings, 2012
    Co-Authors: Thoroskar Relander, Sverre Holos, Jan Vincent Thue

    Abstract:

    Abstract High Airtightness is particularly important in order to achieve energy efficient buildings. Of this reason Airtightness estimation is of interest. Over the past 30 years researchers have worked on Airtightness estimation. This article is divided into two parts. The 1st part deals with earlier work on Airtightness estimation. It is seen that there are relatively few references in the literature that deal with estimation of Airtightness. None of the reviewed references argue that Airtightness measurements can be replaced by estimates. The only reference that deals with Airtightness estimation of wood-frame houses with high Airtightness did not manage to find a correlation between the estimated and the measured Airtightness. For a contractor what really matters is not an estimate of the Airtightness of the finished building, but a reliable means to be sure of reaching the Airtightness requirement. It is therefore customary to perform blower-door tests stepwise during the construction process. First the Airtightness of the building with the wind-barrier is measured, n 50w . Then the Airtightness of the finished building that also has a vapour barrier is measured, n 50f . The Airtightness requirement is set for n 50f . Of various reasons it is not given that n 50f n 50w for a given building, and consequently one should have an idea of what an upper limit of n 50w should be in order to be confident to reach the n 50f requirement. In the 2nd part of the article it will be shown how this upper limit of n 50w can be found by statistical analysis based on systematic measurements of n 50w and n 50f as part of a quality assurance system.

  • the influence of the joint between the basement wall and the wood frame wall on the Airtightness of wood frame houses
    Energy and Buildings, 2011
    Co-Authors: Thoroskar Relander, Bjørnar Heiskel, John Tyssedal

    Abstract:

    Abstract An airtight building envelope is crucial to achieve energy efficient buildings. The Norwegian Airtightness requirements have become stricter, leading to an increased interest in methods for ensuring airtight building envelopes. The joint between the basement wall and the wood-frame wall is known to be a typical air leakage path. Using laboratory measurements and a statistical experimental design the influence of the 3 factors flatness of the basement wall, the sealing method used in the joint and the load between the wood-frame wall and the basement wall is investigated. The influence of this air leakage on real wood-frame houses is also estimated. The results show that the flatness of the basement wall top surface has a considerable influence on the air leakage, a flatter surface generally leading to less air leakage. The sealing materials have widely differing Airtightness properties. The least airtight sealing materials, which also are the non-malleable ones, turn out to be sensitive to the flatness of the basement wall and the load on the wall. The estimates of the influence of the air leakage on real wood-frame houses show that the least flat surfaces should be avoided for the non-malleable sealing materials. It is also seen that if the least favourable sealing method is used, or if the sealing is forgotten, the influence on the total Airtightness can be remarkable. However, the results also show that it is possible to make the influence of the joint on the total Airtightness negligible.

Jan Vincent Thue – 2nd expert on this subject based on the ideXlab platform

  • Airtightness estimation a state of the art review and an en route upper limit evaluation principle to increase the chances that wood frame houses with a vapour and wind barrier comply with the Airtightness requirements
    Energy and Buildings, 2012
    Co-Authors: Thoroskar Relander, Sverre Holos, Jan Vincent Thue

    Abstract:

    Abstract High Airtightness is particularly important in order to achieve energy efficient buildings. Of this reason Airtightness estimation is of interest. Over the past 30 years researchers have worked on Airtightness estimation. This article is divided into two parts. The 1st part deals with earlier work on Airtightness estimation. It is seen that there are relatively few references in the literature that deal with estimation of Airtightness. None of the reviewed references argue that Airtightness measurements can be replaced by estimates. The only reference that deals with Airtightness estimation of wood-frame houses with high Airtightness did not manage to find a correlation between the estimated and the measured Airtightness. For a contractor what really matters is not an estimate of the Airtightness of the finished building, but a reliable means to be sure of reaching the Airtightness requirement. It is therefore customary to perform blower-door tests stepwise during the construction process. First the Airtightness of the building with the wind-barrier is measured, n 50w . Then the Airtightness of the finished building that also has a vapour barrier is measured, n 50f . The Airtightness requirement is set for n 50f . Of various reasons it is not given that n 50f n 50w for a given building, and consequently one should have an idea of what an upper limit of n 50w should be in order to be confident to reach the n 50f requirement. In the 2nd part of the article it will be shown how this upper limit of n 50w can be found by statistical analysis based on systematic measurements of n 50w and n 50f as part of a quality assurance system.

  • Airtightness estimation—A state of the art review and an en route upper limit evaluation principle to increase the chances that wood-frame houses with a vapour- and wind-barrier comply with the Airtightness requirements
    Energy and Buildings, 2012
    Co-Authors: Thoroskar Relander, Sverre Holos, Jan Vincent Thue

    Abstract:

    Abstract High Airtightness is particularly important in order to achieve energy efficient buildings. Of this reason Airtightness estimation is of interest. Over the past 30 years researchers have worked on Airtightness estimation. This article is divided into two parts. The 1st part deals with earlier work on Airtightness estimation. It is seen that there are relatively few references in the literature that deal with estimation of Airtightness. None of the reviewed references argue that Airtightness measurements can be replaced by estimates. The only reference that deals with Airtightness estimation of wood-frame houses with high Airtightness did not manage to find a correlation between the estimated and the measured Airtightness. For a contractor what really matters is not an estimate of the Airtightness of the finished building, but a reliable means to be sure of reaching the Airtightness requirement. It is therefore customary to perform blower-door tests stepwise during the construction process. First the Airtightness of the building with the wind-barrier is measured, n 50w . Then the Airtightness of the finished building that also has a vapour barrier is measured, n 50f . The Airtightness requirement is set for n 50f . Of various reasons it is not given that n 50f n 50w for a given building, and consequently one should have an idea of what an upper limit of n 50w should be in order to be confident to reach the n 50f requirement. In the 2nd part of the article it will be shown how this upper limit of n 50w can be found by statistical analysis based on systematic measurements of n 50w and n 50f as part of a quality assurance system.

  • the influence of structural floors on the Airtightness of wood frame houses
    Energy and Buildings, 2011
    Co-Authors: Thoroskar Relander, Staf Roels, Jan Vincent Thue, Geert Bauwens, Sivert Uvslokk

    Abstract:

    Energy use in buildings has come more into focus in recent years. An airtight building envelope with a low infiltration is a definite prerequisite to achieve an energy efficient building. Recently the Norwegian Airtightness requirements have become stricter. This leads to an increased focus on airtight constructions and methods. Platform constructed structural floors are widely used in Norway. Air leakages are frequently observed in connection with structural floors, both at the wall/floor and wall/ceiling junction and as leakages into the floor or into the ceiling. This article discusses the importance of the leakages in platform constructed structural floors on the Airtightness of wood-frame houses. This is done by laboratory measurements of vapour barriers and wind-barriers mounted on a wall with structural floor beams. The results show that the Airtightness performance of the vapour barrier can be made almost as good as the wind-barrier. However, this is quite labour-intensive. With a properly mounted wind-barrier, the influence of the structural floors on the Airtightness of a wood-frame house can be made negligible.

Arnold Janssens – 3rd expert on this subject based on the ideXlab platform

  • Airtightness and watertightness of window frames comparison of performance and requirements
    Building and Environment, 2016
    Co-Authors: Nathan Van Den Bossche, Arnold Janssens

    Abstract:

    Abstract Airtight buildings require airtight windows. To date little information is available on the typical Airtightness of window frames, and the aptitude of current regulatory performance levels for windows in respect to very airtight buildings is highly uncertain. Between 1997 and 2012, 437 windows were tested in laboratory conditions for certification; the most important results in respect to Airtightness and watertightness are reported here. For both parameters, vinyl frames yield slightly lower performance than aluminum or wooden windows. Single windows perform best, followed by double, composed and sliding windows. Window Airtightness performance levels were calculated based on various building geometries and Airtightness targets. Reducing the impact of windows on the overall building Airtightness to 5% is realistic and feasible, even for very airtight buildings. The test results clearly demonstrate that Airtightness, watertightness and resistance to wind loads are partially correlated. A comparison of guidelines and standards on watertightness of windows shows large discrepancies and little uniformity. Most turn-and-tilt windows show good watertightness and can be applied to very exposed conditions, whereas sliding windows have a limited scope.

  • durability and measurement uncertainty of Airtightness in extremely airtight dwellings
    International Journal of Ventilation, 2016
    Co-Authors: Wolf Bracke, Nathan Van Den Bossche, Jelle Laverge, Arnold Janssens

    Abstract:

    AbstractIn this paper a series of leakage tests is presented on extremely airtight dwellings, studying the durability of the Airtightness level and the measurement uncertainty involved. All houses subjected to testing are certificated passive houses, meaning the maximum air leakage rate upon completion was n50 < 0.6 h-1 air changes per hour at 50 Pa pressure difference.In the literature, repeatability and reproducibility issues have been discussed by several authors, along with influences of weather conditions. However, it remains unclear to what extent the available uncertainty intervals are relative or absolute. With the current tendency towards extremely low leakage levels and the introduction of Airtightness requirements in building codes, the further exploration of this issue has become crucial.Four aspects concerning air leakage tests are examined: the repeatability and reproducibility of the fan pressurization results in extremely airtight houses, the impact of weather conditions on the measurement…

  • Airtightness of the window-wall interface in wood-frame walls
    , 2014
    Co-Authors: Wolf Bracke, Nathan Van Den Bossche, Lynn Devos, Silke Maertens, Arnold Janssens

    Abstract:

    Due to the increased focus on Airtightness in the current building practice, a better understanding of air leakage rates through different building components and building interfaces is required. This paper investigates the Airtightness of the window-wall interface in wood-frame constructions through a literature review and experimental study. Different wall setups, window installation methods and air sealing solutions were tested resulting in 20 different configurations. Air leakages rates ranging from 0.00 up to 3.66 m3/h.m at 50 Pa are measured and recommended configurations and installation techniques are discussed. The results show that a passive house level Airtightness is achievable when using spray-in-place polyurethane foam or airtight membranes, if some general guidelines are followed.