Blower Door Test Research Articles

An approach to modelling envelope airtightness in multi-family social housing in Mediterranean Europe based on the situation in Spain

Building hygrothermal performance, indoor air quality and energy consumption depend heavily on envelope airtightness. Over the last three decades, single-family dwellings have been amply studied in this respect by researchers in North Europe, the United States and Canada. However, very few studies have been conducted on airtightness in multi-family housing in warm climates such as Mediterranean Europe. This paper aims to enhance the understanding of building airtightness in early twenty-first-century multi-family buildings in southern Spain. Blower Door tests were conducted in 45 units in seven such buildings. The main airtightness parameter values found are reported and compared to the data for other buildings in southern Europe. The paper includes a statistical analysis of the findings, characterises building types and describes the protocol used to identify and quantify air leakage pathways. The conclusion drawn is that although a rough predictive model can be developed, the results are widely scattered due to the impact of the random component of manual construction, even in buildings with identical construction characteristics and types. The values recorded are nonetheless consistent with the findings for other European surveys.

Seeming Air Tightness of Construction Partitions

The aim of the paper is to highlight the problem of the seeming air tightness of construction partitions in buildings. In many cases, construction partitions meet the criteria for required air tightness. There are no cross air channel flows through a building envelope, and the Blower Door test is positive, which points to an airtight construction, but the building demands more heat than that due to calculations. The reason for this problem is in wind washing the porous and fibrous materials embedded in the building envelope. Seeming air tightness may be one of the most important reasons why, in construction partitions with the required thickness of thermal insulation, the heat transfer coefficient exceeds the limit value.

Energetic and Acoustic Renovation of Residential Buildings of the 1950s to the 1970s

One third of the residential buildings in Switzerland were built in the period from 1946 to 1980. Due to this large number buildings from the mentioned time period shape appearance of urban districts decisively in many Swiss cities. As these buildings do not fulfill current standards regarding energy efficiency, heat protection and sound insulation have to be renovated in the years ahead. To preserve the cityscape the renovation measures should be done with care and the outer appearance of the individual buildings should not be changed to a large extent.A research project with the title “Energetic and acoustic renovation of residential buildings of the 1950s to the 1970s” was carried out by the Department of Architecture, Wood and Civil Engineering of the Bern University of Applied Science (BFH AHB). The research project's objective was to reduce the lack of knowledge regarding the existing state of buildings from the mentioned time period in terms of energy performance and sound insulation. By means of statistical data, covering the residential building stock of the commune of Biel, reference building types for the 1950s, 1960s and 1970s were determined. In collaboration with housing cooperatives from Biel three representative residential buildings were selected and documented, one for each decade. As part of detailed structural survey of the existing buildings the energetic and acoustic values and properties regarding the reference building of the 1950s as well as the reference building of the 1960s were determined. Amongst other things the constructions of the components were inspected in a non-destructive way and the heat transfer coefficients of the heat transferring components were calculated. Blower door tests to evaluate the air tightness of the building envelopes as well as acoustic measurements for determining the impact sound protection and the protection against airborne noise were done. Within the research project exemplary concepts for gentle energetic and acoustic renovations were developed for the two reference buildings. In this paper the research project's results with main focus on the reference building of the 1950s are presented.

Dwelling airtightness: A socio-technical evaluation in an Irish context

This paper evaluates the relationship between envelope airtightness, correlated energy performance and occupant sensitivity pre- and post-energy efficient fabric upgrading of semi-detached social housing in Ireland. The climate corrected energy impact of the infiltration is derived from standard blower door test results and compared with modelled performance. Semi-structured interviews were used to explore the human and indoor environmental quality impact of the upgrading.Testing revealed large variations in airtightness levels and characteristics between similar dwellings. Measured and modelled airtightness results differ by up to 89%. Fabric upgrading not incorporating airtightness improvement measures yielded an average incidental 22% improvement in envelope airtightness. This equates to an estimated average 361 kWh energy savings per annum per dwelling. Occupants were generally pleased with the improvements, but many were unhappy with the ventilation systems installed as part of the upgrading.Airtightness plays an important role in the energy performance and comfort of dwellings. However, this concept is little understood by occupants and often not included as part of upgrading strategies. Further investigation is required to inform and improve energy performance calculation methodologies. There is also a need to consider the impact of upgrading works on comfort. Occupants need to be educated about the benefits of maintaining good ventilation and limiting infiltration.

AIR TIGHTNESS OF STRAW BALE CONSTRUCTION

Straw bale construction offers a renewable, sustainable and proven alternative to mainstream building methods; still, little is known about its airflow characteristics. To this end, the intent of this paper is to evaluate airtightness of fully constructed and plastered straw bale walls as well as individual plain straw bales. The first experiment entailed measuring the influence of straw bale orientation on airflow characteristics with the finding that straw bale considered alone has poor air flow-retarding characteristics and that plaster is the primary air barrier. A second experiment involved thirty plastered straw bale specimens using three different plaster types. From this experiment, a crack grading system was developed and is herein proposed as a tool to evaluate plaster performance as an air barrier. A third experiment validated the crack grade system through application on four fully constructed straw bale walls. Practical use of the crack grading system was demonstrated on a case study straw bale house in Radomlje, Slovenia, where the predicted air tightness results were validated through comparison to results of blower door tests.

POWER CONSUMPTION COMPARISON OF FIVE BUILDING ENVELOPES IN THE NORTHERN PRAIRIE CLIMATE OF MANITOBA

The energy efficiency of a building depends on building envelope performance. The results presented in this paper are the first of a long-term building envelope research project at the Alternative Village at the University of Manitoba in Winnipeg, Manitoba, Canada. Five test buildings were constructed using the following systems: two wood frames with fiberglass batt insulation and dense pack cellulose, one polyurethane structural insulated panels (PUR SIP), and two with the Stay in place PVC concrete form building system using 102mm and 204mm of concrete externally insulated with 102mm of expanded polystyrene foam. All of the buildings had a common foundation and roof system with a footprint of 23.8 m2. Blower door tests were conducted to determine air tightness. Each structure was heated with an electrical resistance heater and maintained at a constant internal temperature. The thermal gradient through the wall and power consumption were monitored. The study period discussed in this report represents the main heating season from October 2011 to April 2012 consisting of 209 days. Based on the power consumption, the PUR SIP consumed the least at 2498 kWh, while the 204 mm Stay in place PVC concrete form building used the most at 2898 kWh for the same time period. The thermal gradient through the cross section of the wood frame structures was compared through the cavity insulation and at the stud. It was found that the cellulose building provided better thermal resistance along the stud when compared to the fiberglass batt insulation.

Air infiltration assessment for industrial buildings

This work focuses on air-tightness and air-infiltration of industrial buildings of light steel structure. Extensive measurements of leakages in typical building components and connections in industrial buildings were carried out in a specially built air-tightness test stand. Typical leakages were detected and reduced. Measurements of the volumetric flow through single leakages were compared to results of blower door tests of large industrial buildings. The measurement data gained in the test stand was further used for transient air-flow network simulations coupled with the software TRNSYS. Based on a database of more than 4000 industrial buildings, 28 typical building shapes were defined and different inside temperature profiles were assumed. Each building was modeled and simulated with up to 84 defined cracks. The cracks were based on the measurements in the test stand and represent a typical leakage distribution of industrial steel buildings. In total 140 different simulations were used to create a new infiltration model. This model provides monthly coefficients that consider the seasonal cycle during the year as well as the building height, size and inside temperature. This new model is easy to implement in energy balance calculations and helps determining energy demands even with steady state methods with greater precision.

Estimation of air infiltration for Australian housing energy analysis

This study presents an integrated air flow model for AccuRate, a benchmark housing energy star-rating tool widely used in Australia. The model was developed by implementing a network multi-zonal infiltration model into an existing large opening model. Case studies using 10 houses in Melbourne, Australia, showed that on average the predicted infiltration rates are within 12.6% of the blower-door test results with a standard deviation of 1.6%. The model study also showed that on average the infiltration rates of the 10 houses could be reduced around 52% by sealing major air leakage pathways, which can result in an average of 7% reduction in the annual space heating and cooling loads for the 10 houses. It was also found that an annual hourly energy performance simulation using the new air flow model requires around 15 min in comparison with around 1 min using the existing simple infiltration model in the AccuRate engine.

The energy impact of infiltration: a study on buildings located in north central Spain

Improving the energy efficiency of the thermal conditioning of buildings is an international priority. Along this line, there have been major advances in the insulation of enclosures and the equipping of facilities. The need for building ventilation has an enormous impact on the environmental energy consumption evaluation. Filtration resulting from imperfections in enclosures and partitions always accompanies narrow ventilation flow, increasing the unabated consumption of energy. The present research study establishes an evaluation procedure for this excess energy consumption via an experimental study carried out in various buildings located in the north and central part of Spain. The procedure, commonly called the Blower Door Test, is based on standards EN 13829 and ISO 9972. The work is composed of the following sections: a description of the air entry processes in buildings, an experimental study and calculation of the airtightness of enclosures, a discussion of the energetic effects of infiltration and conclusions.

Proposal of Acceptable Air Tightness Classes for Buildings in Chile

In order to limit the energy demands the building ordinances establish requirements for reducing to acceptable levels the energy losses and/or gains. This situation obliges to define acceptable standards for thermal parameters. This report covered the evaluation of representative samples of Chilean homes built in 2007 and 2010 in the 54 provincial capitals of the country. A sample of 191 units was determined, representative of the construction, materials and housing architecture in Chile. Experimental techniques were used (Blower Door test) for obtaining air tightness of samples; numerical models (LBL Model) for relating the air tightness properties with the weather characteristics of every province in order to obtain infiltration coefficient classified by type of construction and province; simulation techniques (Thermal Analysis Simulation Software) for determining the energy demand of housing The Air Tightness classes are established combining two criteria: the one that measures the current state of air tightness of housings and other that limits the infiltration demand to a limit value that explains itself economically.

Air Tightness Performance of Residential Timber Frame Buildings

Energy consumption statistics in 2005 from the Korea Energy Management Corporation show that building energy usage was about 24.2% of total domestic energy consumption, and 64% of total building energy usage was consumed by residential buildings. Thus, about 10% of total domestic energy consumption is due to the heating of residential buildings. Building energy can be calculated by the configuration of the building envelope and the rate of infiltration (the volume of the infiltration of outdoor air and the leakage of indoor air), and by doing so, the annual energy usage for heating and cooling. Therefore, air-tightness is an important factor in building energy conservation. This investigate air infiltration and various factors that decrease it in timber frame buildings and suggest ways to improve air-tightness for several structural types. Timber frame buildings can be classified into light frame, post and beam, and log house. Post and beam includes Han-ok (a Korean traditional building). Six light frame buildings, three post and beam buildings, one Korean traditional Han-ok and a log house were selected as specimens. Blower door tests were performed following ASTM E779-03. The light frame buildings showed the highest air-tightness, followed by post and beam structures, and last, log houses.

기존 단독주택의 침기량 산정법에 관한 연구

The purpose of this study is to find the infiltration of detached houses, for energy consumption analyses. The pressurization and depressurization method is used to determine infiltration. Blower door tests are expressed in terms of ACH 50, which stands for the hourly air change rate at 50 Pa of fan pressure. The ACH 50 of existing Detached Houses ranges from 5 to 50. Air infiltration is related to construction year and accuracy, maintenance conditions, and so on. When estimating the infiltration of random detached houses, the year used can be the base value of the infiltration rate from 0.25 to 2.0 times/h. The maintenance conditions, construction accuracy and repair affect the air infiltration 0 to 0.5 times/h, 0 to 0.3 times/h, 0 to 1 times/h, respectively.

신한옥 침실 공간의 기밀성능 평가 연구

The purpose of this study is to evaluate the airtightness performance of New Han-ok and to supply fundamental data for standards establishment. Air leakage testings were accomplished by means of blower door test in 26 bedrooms of 16 Han-oks located in Jeonnam happy villages. Followings are results. 1) Air change per hour at 50 Pa(ACH50) is located on 8.42~78.38. 2) No correlation between ACH50 and volumes, floor area, above grade surface area. 3) The more wood structural elements are exposed, attached spaces, wooden sliding and casement windows, the less airtightness performance. 4) An Airtightness with ACH50/20(NL, Normalized leakage) is located on 0.42~3.92 and building leakage class following F(4%), G(11%, sufficiently leaky, No need mechanical ventilation), H(4%, Need of cost-effective tightening), I(31%), J(50%) by a single-story house the normalized leakage of ASHRAE.

패시브 디자인을 적용한 주택의 기밀성에 관한 실측 사례 연구

Today, the world energy consumption in buildings occupies more than 30%. In our country, the energy consumption in buildings also occupies 25% of the entire national energy consumption. With the increasing demand of energy saving in architectural fields, there is a more interest in low-energy construction. For these low-energy housings, our country is planning to apply the energy-saving design standards at the level of passive houses in 2017. However, there is still a limitation in energy saving only with the standards on the performance of envelope in buildings. This means that unless a building is airtight even though it was well-insulated, cooling and heating energy consumption will increase due to the infiltration and leakage. Therefore, this study aims to make a comparative analysis of airtight performance by conducting a blower door test on the housings applied with passive designs, analyze the reasons why most houses fall short of the airtightness standards, and complement the airtightness problems in the inadequate parts of the buildings in order to save building energy.

Analysis and Repercussions of the Updating of the Spanish Regulation Regarding Ventilation and Infiltration

The Spanish Technical Building Code is one of the three royal decrees that were approved in Spain as a consequence of the transposition of the European Directive on the energy performance of buildings (2002/91/EU, 2002). One basic document of the Technical Building Code deals with the limitations of building energy demands. Nowadays, due to the recast of the European Directive on the energy performance of buildings (2010/31/EU, 2010), a revision process of the current regulations has begun, starting with the Technical Building Code, with its first revision envisaged for 2012. In this paper we, as collaborators in this updating process, describe and analyse the main changes regarding ventilation and infiltration that the “new” Technical Building Code (TBC) is going to introduce. These main changes cover:1. The calculation methodology;2. The ventilation technologies that can be considered;3. The default values and the data that the user can supply to assess particular cases.Basically, these changes make it possible to move from a previous regulation that considered:1. One indoor pressure and one outdoor pressure, assuming all the indoor spaces as a single-zone (calculation methodology EN 13465 (2004));2. A constant extraction flow for 24 hours a day, without the possibility of using a control system;3. No possibilities of changing the sizing of vents, default behaviour curve of the vents and air permeability of opaque elements according to EN 13465 (2004).To a new regulation that considers:1. One indoor pressure and one outdoor pressure (calculation methodology EN 15242 (2007)) but keeping indoor zoning that allows calculating (using mass conservation) the airflow between zones;2. The possibility of using a control system allowing different flows each hour for a demand controlled ventilation scheme and pre-heating of supply air flow;3. The possibility of sizing vents, using self-regulating vents and changing the air permeability of opaque elements, for example if a blower-door test has been carried out.

Building leakage analysis and infiltration modelling for an Italian multi-family building

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-storey, six-unit, multi-family building which can be considered representative of the existing recently renovated Italian building stock was characterized by means of a series of fan pressurization tests. The performed blower door tests are documented and results of the data analysis are reported and discussed. A simulation model was developed; simulations were performed to analyse in detail the winter magnitude of air infiltration. Winter is usually detrimental to IAQ, as severe outdoor weather prompts occupants to keep closed any opening that could allow cold drafts into their homes. Modelling results were validated on the basis of a 3-week monitoring campaign. The developed model enabled to estimate the variation with time of infiltration rates and therefore the influence of infiltrating air on the resulting heat loss and IAQ. Numerical predictions were derived using the EnergyPlus simulation tool which allowed to combine whole building thermal simulation and detailed multi-zone airflow modelling. Results show that, during the considered heating season (October–April), the average air change rate due to infiltration was approximately 0.1 h−1. It was concluded that infiltration cannot be relied upon to provide adequate ventilation air and, if not assisted by other means of ventilation, IAQ deterioration is likely to occur.

The Importance of a Fan Location in the Front Door in Measuring of the Air Permeability by the Blower Door Test

The value of air permeability, or the value of n50 provides important information about the impermeability of the building envelope and thus the quality of internal environment of the building. It is also one of the main evaluation criteria in classifying energy efficient buildings. Air permeability is determined by Blower Door Test where the fan blows air in or out from the measured area. The measurement is performed in a overpressure and afterwards in a underpressure during which the leaks are detected. The frame is usually placed into the front door which themselves is a weak part in the building envelope, and thus the rate of leakage completely denies. The effect of leakage of the front door is so significant that it can often cause a misclassification of the energy efficient buildings. We have tested this hypothesis by Blower Door Test on a passive timber construction build in 2007 during which we have measured the object in position of measuring device placed in the front door and the balcony door that are not encumbered by leaks caused by a security hardware and by other specific elements

Technical note: Airtightness of older-generation energy-efficient houses in Saskatoon

The aim of this study was to collect long-term in-service energy efficiency data from older-generation energy-efficient houses built in Canada in the past decades. Six houses with highly insulated building envelope assemblies built (or retrofitted) from 1979 to 1992 in the Saskatoon area were inspected during March 2012. As typical energy-efficient houses for this area, all were built with double 2 × 4 stud walls with the gap between walls ranging from 4 to about 12 in and with nominal wall insulation varying from RSI * 6.34 (R* 36) to RSI 10.57 (R 60). The roof insulation ranged from RSI 10.57 (R 60) to RSI 14.09 (R 80). The below-grade walls were also well insulated, and these were mainly permanent wood foundations. Polyethylene was used as a combined air barrier and vapour barrier for the building envelopes. The major results included the following: the airtightness values based on blower-door tests ranged from 0.78 to 2.55 air changes per hour at 50 Pa measured under normal operation conditions, with four houses below 1.50 air changes per hour at 50 Pa after 20–30 years. The No. 2 house had an original airtightness of 0.29 air changes per hour at 50 Pa and 0.22 air changes per hour when the windows were sealed with masking tape after the energy retrofit in 1982. The airtightness was measured to be 1.23 air changes per hour at 50 Pa in this survey after the owner installed new windows without properly sealing the interior air barrier. The No. 4 house had an airtightness of 0.78 air changes per hour, while the original airtightness test was 0.47 air changes per hour when the house was built over 20 years ago. All the six houses had EnerGuide Rating System of over 80, and one had a remarkable EnerGuide Rating System of 87. Windows and ventilation air were identified to be the largest heat loss components, followed by basement and exterior walls.

Influence of Air-tightness on Heat Energy Performance in Post and Beam Building with Exposed Wood Frame

Han-green building is one of the modernized Korean traditional buildings developed by Korea Forest Research Institute. This building was developed to increase the competitiveness of Korean traditional building using state-of-art technologies; hence Han-green building has the inherent characteristics of traditional building such as exposed wood frame in wall. Because of discontinuity in wall by the exposed wood frame, there is a concern on heat-air leaking in terms of energy performance. In this study, air-tightness of Han-green building was evaluated to investigate the influence of gaps between frames and in-fill walls. Blower door test was carried out to evaluate the air-tightness, and air-change rate (ACH50) was evaluated by averaging four set of pressurization and depressurization test. The air-change rate of Han-green house was 5.91 <TEX>$h^{-1}$</TEX>. To improve energy performance of Han-green house, thermal infrared images of Han-green house were taken in winter with heating to find out where the heat loss occurred. It was found that the building lost more heat through gaps between frames and in-fill walls rather than through other parts of this building. After covering all the gaps by taping, the blower door test was performed again, and the air-change rate was improved to 5.25 <TEX>$h^{-1}$</TEX>. From this analysis, it was concluded that the heated air can leak through the gaps between frames and walls. Therefore, when one designs the post and beam building with exposed frame, the detail design between frame and wall needs to be carefully dealt. However, Han-green building showed relatively high air-tightness comparing with other country research results.

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

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, n50w. Then the airtightness of the finished building that also has a vapour barrier is measured, n50f. The airtightness requirement is set for n50f. Of various reasons it is not given that n50f<n50w for a given building, and consequently one should have an idea of what an upper limit of n50w should be in order to be confident to reach the n50f requirement. In the 2nd part of the article it will be shown how this upper limit of n50w can be found by statistical analysis based on systematic measurements of n50w and n50f as part of a quality assurance system.