air leakage

It has already been proved that air leakage causes a great impact in the energy performance of buildings in cold climates. In recent years, many studies have been carried out in northern Europe, US and Canada. Regulations in these countries establish maximum air leakage rates for the construction of new dwellings and the refurbishment of the existing ones. However, there is a lack of knowledge relating to the housing stock in Spain.

There are several methods for measuring air tightness that may result in different values and sometimes quite different uncertainties. The two main approaches trade off bias and precision errors and thus result indifferent outcomes for accuracy and repeatability.  To interpret results from the two approaches, various questions need to be addressed, such as the need to measure the flow exponent, the need to make both pressurization and depressurization measurements and the role of wind in determining the accuracy and precision of the results.

Air infiltration holds a central role in building energy consumption and is associated to several building physics phenomena. Air infiltration in buildings due to wind-induced pressure is a complex process, strongly influenced by the turbulent nature of wind. This extended summary highlights the findings of a series of studies with focus on unsteady wind and its impact on air exchangesin buildings. The focus is on wind gustiness and its relation to air infiltration under natural conditions.

Mastering building airtightness is essential to meet the requirements of current and future building codes, not only for saving energy but also for ensuring moisture safety. Perfect airtightness is difficult to achieve: failures are often observed, due to bad design or poor workmanship. Some published investigations proved that leaking air mostly flows through porous material and thin air channels, due to material imperfections and construction tolerances.

Durability of the building envelope is important to new homes that are increasingly built with improved levels of airtightness. It is also important to weatherized homes such that energy savings from retrofit measures, such as air sealing, are persistent. This paper presents a comparison of air leakage measurements collected in November 2013 through March 2014, with two sets of prior data collected between 2001-2003 from 17 new homes located near Atlanta, GA, and 17 homes near Boise, ID that were weatherized in 2007-2008.

The airtightness test of the building is one of a few building envelope measurements used in practice, which is quantitative, not just qualitative as e.g. infrared thermography. The so-called blower-door test result may be a measure of the building design and construction quality and could also be used for the energy demand for heating and cooling analyses.

This study presents a comparison of air leakage measurements collected recently (November 2013 to March 2014) with two sets of prior data collected between 2001-2003 from 17 new homes located near Atlanta, GA, and 17 homes near Boise, ID that were weatherized in 2007-2008. The purpose of the comparison is to determine if there are changes to the airtightness of building envelopes over time. Durability of building envelope is important to new homes that are increasingly built with improved levels of airtightness.

In this study, the characteristics of the movement of chemical compounds in the concealed spaces and indoor spaces in houses were investigated using building cut models and a simulation program Fresh2006. The equivalent leakage areas in the concealed spaces were measured using cut models of wooden structures: a common wooden structure, an improved wooden structure and a wooden (2 inch x 4 inch) stud structure.

Accidental dispersion of toxic gas clouds may occur around industrial platforms or during hazardous materials transportation. In case of such a toxic risk, the best protection strategy is to remain inside a building and seek refuge in an airtight room identified as “shelter” until the toxic cloud has finally been swept off. This strategy called “passive shelter-in-place” also includes obstructing all external openings and turning off all mechanical ventilation systems

Air leakage and other diagnostic measurements are being added to LBNL’s Residential Diagnostics Database (ResDB). We describe the sources of data that amount to more than 80,000 blower door measurements. We present summary statistics of selected parameters, such as floor area and year built. We compare the house characteristics of new additions to ResDB with prior data.