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The building airtightness is essential to achieve a high energy performance. In most countries however, it is not mandatory to measure the airtightness. In the Netherlands it is common practice to ...

Addressing the airtightness of the building envelope is key to achieve thermal comfort, good performance ofventilation systems and to avoid excessive energy consumption. Previous studies have estim...

The air-tightness performance of residential buildings in China is not fully investigated. This study intends to investigate the air-tightness performance of an ultra-low energy building in a cold area of China. The air-tightness of the building envelope was measured using blower door method and the whole year air infiltration of the building was simulated by a multi-zone network airflow model based on the air-tightness test results. A thermal infrared imager and a smoke pencil were used to find out the typical air leakage places in the building envelope. The leakage areas of the typical air leakage places are found by measuring the whole building and then sealing the corresponding component and determining the reduction in the building effective leakage area. Test results show that the air change rates of the building at the pressure difference of 50 Pa (ACH50) under the depressurization and pressurization modes are 0.5 and 0.49 h−1, respectively. Simulations show that the air change rate of building und...

Author(s): Chan, Wanyu R; Walker, Iain S.; Sherman, Max H. | Abstract: 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 purpose of the comparison is to determine if there are changes to the airtightness of building envelopes over time. The air leakage increased in all but one of the new homes, with a mean increase of about 25%. The weatherized homes also showed an increase in the mean air leakage (12%). A regression analysis was performed to describe the relationship between prior and current measurements in terms of normalized leakage (NL). The best estimate of the ageing factor predicts a 15% increase in NL over ten years. Further analysis using ResDB data (LBNL’s Residential Diagnostic Database) showed the expected changes in air leakage if ageing were modelled. These results imply the need to examine the causes of increased leakage and methods to avoid them. This increase in leakage with time should be accounted for in long-term population-wide energy savings estimates, such as those used in ratings or energy savings programs.

Although standards for single-zone air leakage tests are widely used, there are no existing standards for several multi-zone cases including: 1) testing air leakage between adjacent zones or 2) testing leakage to the outside from a single unit in a multi-zone building. While a range of test procedures have been used to determine inter-zone leakage using fan-pressurization, the accuracy of the methods can vary significantly. Using field measurements and simulations, we compared the uncertainty in the leakage between two adjacent zones for different measurement and calculation methods. The most accurate method for determining leakage between two adjacent zones using a single blower door has 25% uncertainty and the most accurate two-door test has 16%. In multi-family housing buildings, air leakage from a single zone to the outside is often measured by pressurizing adjacent units to the same test pressure, i.e., a guarded test approach. We investigated how two common sources of uncertainty affect zone...

In 1998, NIST published a review of commercial and institutional building airtightness data that found significant levels of air leakage and debunked the “myth” of the airtight commercial building (Persily, 1998). Since then, NIST has expanded and maintained a database of whole building envelope leakage measurements of U.S. commercial and institutional buildings. In addition to building leakage values collected from research publications, low-energy building programs and private pressurization testing firms, the database includes basic building characteristics such as year built, building type, floor area, number of storeys, location, and wall construction type for many of the buildings. The purposes of the database are to support the design and construction of low-energy buildings, to establish default values for building simulation, to estimate the energy savings potential of airtightness requirements in standards and codes, and to identify opportunities for additional improvements in building a...

The objective of this investigation is to determine air infiltration in buildings using sound transmission loss (STL) through various types of holes and cracks. The method is based on the use of a sound source that radiates sound waves at a known frequency inside the building and two sound level meters, which measure sound pressure level inside and outside the building. To develop a correlation between STL and air infiltration, experiments have been performed using various types of materials. A test chamber was divided in two sub-chambers to simulate interior and exterior air conditions. Various materials, each with a small hole of varying shapes and sizes, were positioned between the two sub-chambers. A pressure difference has been generated between the sub-chambers and air infiltration in each experiment was measured through each hole. Filed testing in several buildings has been performed to determine air infiltration. The results of field measurements compared with the blower door readings show that th...

Air tightness is an important property of building envelopes. It is a key factor in determining infiltration and related wall-performance properties such as indoor air quality, maintainability and moisture balance. Air leakage in U.S. houses consumes roughly 1/3 of the HVAC energy but provides most of the ventilation used to control IAQ. 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 in different 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. This article uses two large datasets of blower door measurements to reach the following conclusions. For most tests the pres...

The presented paper aims at detailing the results of an investigation that was recently conducted in Italy to evaluate the contribution infiltration makes to meeting ventilation needs in a recently renovated apartment building and the corresponding energy costs. It is years that increasing importance has been placed on the energy efficiency in residential buildings as about 70% of the existing Italian residential building stock was built before 1976 (i.e. before any measure related to the energy efficiency in buildings). As existing dwellings have been traditionally considered ‘leaky’, the actions for improving their energy efficiency have often determined tighter buildings, raising concerns about whether the amount of infiltration is sufficient to provide occupants with acceptable indoor air quality (IAQ). The current state of knowledge on infiltration in multi-family buildings in terms of measuring procedures, corresponding air change rates and airflow patterns was reviewed. The air tightness of a three...

This paper applies established and new testing methods to discover the ventilation performance of various residential building envelope constructions in Australia. Under the definition of 'ventilation performance' we imply the building envelope leakage (or infiltration) of the living space air change rates, the volumetric flow rates and the pathways of air flow between subfloor, living and roof spaces. All of the methods applied and discussed here are on-site, evidence-based performance of actual structures as tested by the Mobile Architecture and Built Environment Laboratory and Air Barrier Technologies. The testing processes primarily involve the Tracer Gas Decay Method (TGDM) and rhe fan pressurisation method (FPM a.k.a 'blower door'). All the measurements are performed with respect to the external wind speed and direction as well as the typical weather parameters. This paper discusses the differences and similarities of both testing methods as well as several other testing procedures that can inform the researcher on air leakage pathways. Findings of a simultaneous TGDM and FPM air leakage rate comparison are also encountered in this paper. One of the most informative testing methods, is the application of three different tracer gasses introduced into different spaces (subfloor, living and roof) to discover pathways of air flow within residential construction.

The National Institute of Standards and Technology (NIST) is conducting a study on the indoor air quality (IAQ) impacts and engineering solutions related to the transport of pollutants from attached garages to residential living spaces. Natural or fan-induced pressure differences across air leakage paths in house-garage (HG) interfaces can result in the transport of the contaminants generated in garages into adjacent living spaces. This paper summarises a literature review on the transport of pollutants from garages to residential living spaces and describes a field study to estimate the range of airtightness of attached garages and of HG interfaces in the United States.Although the body of literature on pollutant transport from attached garages to residential buildings is limited, the studies reviewed provide substantial evidence that transport of contaminants from garages has the potential to negatively impact residential IAQ in either an acute (e.g., carbon monoxide from automobiles) or chronic...