Blower Door Method Research Articles

Effect of Air Infiltration Rate on Energy Consumption of a Residential Building in Bebena, Thimphu

Energy consumption in buildings has been a major concern in the present construction field and the parameters that affect its performance should be carefully studied. Building airtightness is an important contributing factor to the energy consumption of a building. The measurement of air infiltration is widely practiced in some countries of Europe and North America. However, this practice is still rare and uncommon in Bhutan. At present, traditional dwellings of Bhutan have been found to be very leaky as compared to the modern Reinforced concrete structure (RCC) buildings mainly due to construction materials and techniques. The paper consists of air infiltration test carried out by the blower door method at a residential building in Bebena, Thimphu. The test has been followed by a series of data collection and interpretation of the readings obtained on site. The result obtained was air movement of 11.9-h through the building envelope which was satisfactory as in the case of Bhutan but was found to be exceeding the international standard of 3.0-h in accordance to ISO 9972:2015. The average air movement of residential buildings in Bhutan is 11.7-h according to the energy baseline report.

Dependence of measured specific air leakage rate (qE50) on envelope pressure differences and measurement position: a case study in an apartment building in winter conditions

Airtightness of the building envelope has become an important component in achieving ever stricter energy performance levels. However, airtightness measurements using blower door method are dependent on choices made by the specialist conducting the tests. One being the assessment of baseline pressure difference inside the building and position of the measurement equipment. Ideally, the test will be conducted without wind and stack effect which could disturb the envelope pressure measurements. Unfortunately, such conditions seldom exist, especially in colder climates. This increases the appeal of conducting apartment-wise measurements over whole-building measurements as it is far easier to comply with the ISO 9972. However, the apartment-wise method has a relatively random nature due to small share of actual building envelope. This paper investigates the effect of using different measurement positions and pressure levels on the airtightness measurement results. A 5-storey 15m tall residential building was used as a case study and measured as a whole and in select apartments. The results show that the variation caused by different choices of pressure levels, measurement positions etc caused relatively low variations and whole-building measurement should be preferred even if not all baseline and pressure level requirements are not met.

Impact of air infiltration rate on the thermal transmittance value of building envelope

Building envelope plays a crucial role in limiting the heat gains and affects the energy requirement for space cooling directly. To this end, building codes specify overall thermal transmittance values of the building envelope to address the building energy efficiency. However, these values do not consider the heat gains due to infiltration, which is a characteristic of the building envelope. With this context, the objective of this research is to measure the infiltration rates in apartments and propose an infiltration factor to revise the existing equation of the residential envelope transmittance value (RETV), recommended by the building code in India. Herein, the Blower door method is employed to measure the infiltration rates for a total of 20 air-conditioned apartments. Such a study, with the blower door method, has not been reported in India. The measurements show that the infiltration rates vary from 0.53 ACH to 1.63 ACH and are correlated with the window construction characteristics. Simulations are also carried out for estimating the impact of infiltration on the RETV with a calibrated energy model. The sensitivity analysis showed that the heat gain from infiltration accounted for 10%–33% of the overall envelope heat gains. The infiltration factor is derived for different climate zones of India by carrying out a parametric study involving 3072 simulation cases. It was found that 1 ACH of infiltration contributes 5.46, 4.22, and 3.53 W/m2 of RETV in hot-dry, composite and warm-humid climate respectively. A relationship between revised RETV and energy consumption is also established.

Effects of Neighboring Units on the Estimation of Particle Penetration Factor in a Modeled Indoor Environment

Ingress of air from neighboring apartments is an important source of fine particulate matter (PM2.5) in residential multi-story buildings. It affects the measurement and estimation of particle deposition rate and penetration factor. A blower-door method to measure the particle deposition rate and penetration factor has previously been found to be more precise than the traditional decay-rebound method as it reduces variability of PM2.5 ingress from outside. CONTAM is a multi-zone indoor air quality and ventilation analysis computer program to aid the prediction of indoor air quality. It was used in this study to model the indoor PM2.5 concentrations in an apartment under varying PM2.5 emission from neighboring apartments and window opening and closing regimes. The variation of indoor PM2.5 concentration was also modeled for different days to account for typical outdoor variations. The calibrated CONTAM model aimed to simulate environments found during measurement of particle penetration factor, thus identifying the source of error in the estimates. Results show that during simulated measurement of particle penetration factors using the blower-door method for three-hour periods under a constant 4 Pa pressure difference, the indoor PM2.5 concentration increases significantly due to PM2.5 generated from adjacent apartments, having the potential to cause an error of more than 20% in the estimated value of particle penetration factor. The error tends to be lower if the measuring time is extended. Simulated measurement of the decay-rebound method showed that more PM2.5 can penetrate inside if the PM2.5 was generated from apartments below under naturally variable weather conditions. A multiple blower-door fan can be used to reduce the effects of neighboring emission and increase the precision of the penetration estimates.

Blower-door estimates of PM2.5 deposition rates and penetration factors in an idealized room

Particle deposition and penetration in buildings has been widely studied, but the effect of indoor characteristics merits further investigation, so improved experimental methods may be needed. The present study measured indoor and outdoor concentrations of PM2.5 and estimated PM2.5 deposition rates and penetration factors under a variety of different indoor situations, with a novel method (blower-door method). The blower-door method is compared with the standard decay and rebound method for an idealized room (a portable building test cell; 6.08 m [Formula: see text] 2.40 m [Formula: see text] 2.60 m) under eight testing scenarios (empty, cardboard boxes in three arrangements, terry cloth wall covering, and three sets of window holes); run three times to establish the coefficient of variation representing precision. Results show that higher induced indoor–outdoor pressure differences cause a larger variation of estimated effective deposition rate on different indoor surfaces. The deposition rate and penetration factor may be influenced by indoor surface materials. The blower-door method gives higher precision for the estimates, and detects subtle differences in penetration factors, which may be difficult using the decay and rebound method.

Correlation between air and sound propagation to determine air permeability of buildings for single/double wood pane windows

Building air leakage is a very important criterion on which one building could be differentiated from another one. It can lead to a huge impact on several important parameters inside a building, like energy consumption or indoor air quality. There are several possibilities for its determination, and it could be highlighted three major categories: experimental determinations, predicting models or simulations programs. As the experimental approach is difficult to be conducted being weather dependent or time consuming and the predicting models could lead to errors up to 100%, in this paper we aim to present a novel experimental method for determining the air permeability of a building, by measuring the sound pressure level difference between outdoor-indoor of the analyzed façade. An experimental campaign was conducted using the Blower Door method and an acoustic approach determining the impact of the window’s type on the airtightness of a façade. In extension, the correlation between the two transfer phenomena was highlighted throughout a mathematical model. Multiple acoustical parameters that could influence the air leakage determinations were analyzed. The importance of the reverberation time of the analyzed chamber in the acoustical transfer phenomenon was determined and a practical nomogram was developed.

Experimental insights into the airtightness measurement of a house-sized chamber in a sheltered environment using blower door and pulse methods

This paper introduces a comparison study of measuring the airtightness of a house-sized test chamber using the novel pulse technique and a low range blower door method in a sheltered environment. Eight different testing plates were prepared and applied to the improvised envelope of the chamber to establish different leakage characteristics. Each testing plate has a unique opening in its centre, achieved by obtaining different combinations of shape and thickness of the opening. By using the sheltered environment, the vagaries of the natural condition when testing within buildings have been reduced providing a more robust testing environment. This investigation focuses on how the air leakage rate calculated from the measurements made by both techniques compare with each other. Comparable results (0–5.3%) under most scenarios have been obtained. Larger discrepancies (14.6% and 21.8%) were observed in the two airtight scenarios due to insufficient pressure range achieved in a standard pulse test. This finding guided further improvement on the testing performance. Further pulse tests under different scenarios, involving the use of an internal barrier and various locations of the pulse unit were also performed to investigate the uniform pressure distribution and resilience to external interferences. It showed the internal barrier and location had minor impact (1.62%–4.65%) on the test results.

A novel method for measuring air infiltration rate in buildings

Measuring the air infiltration rate in buildings is essential for reducing energy use and improving indoor air quality. This rate has traditionally been determined by means of the blower door method, which is disruptive to building occupants, cannot identify the location of infiltration, cannot provide the infiltration rate for a section of the envelope, and requires considerable effort for setup and tear-down. Therefore, this study has developed a novel technique to measure air infiltration in buildings using an infrared camera. A thermographic image of a building envelope produced by an infrared camera and the measured indoor/outdoor air parameters (velocity, temperature, and pressure) were used to identify the effective crack size and air infiltration rate by means of theoretical heat transfer and fluid mechanics analyses. The proposed method was validated by experimental measurements in an environmental chamber and an office. The experiment in the environmental chamber constructed a small-scale room with known crack size. The experimental setup was comparable to actual conditions. The proposed method was able to predict the crack size within a relative error of 20%. For the experiment in the office, this study used the tracer-gas decay method to measure the air infiltration rate, and the relative error of the calculated air infiltration rate was only 3%.

Building air leakage analysis for individual apartments in North China

There is little known on the airtightness performance of apartment building in China. The present study intends to investigate the airtightness performance of twelve individual apartments from four buildings in China's cold area using the blower door method. The air leakage of two building components of each of the three individual apartments from the 4# building was further investigated by a series of blower door tests. The normality test was performed to the test results, and the correlation coefficients between the air leakage and possible influence factors were analyzed.Test results show that the air change rate of the tested individual apartments at 50Pa changes from 1.14 h−1 to 2.44 h−1 with an average of 1.77 h−1. The check valves at the inlets of the discharge flue and exhaust airway were tested to be leakier than the outer windows and doors in the three measured apartments from the 4# building. Results of statistical analysis show that the data was significantly drawn from a normally distributed population at the 0.05 significance level, and the envelope area and the joint length of the opening part of the windows and doors were identified as the main factors that influence the air leakage of the tested apartments at the 0.05 significance level.

Air-tightness test and air infiltration estimation of an ultra-low energy building

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 under the weather conditions of Dalian changes from 0 to 0.12 h−1 with an average of 0.05 h−1. The typical air leakage places of the building were the reserved holes in the building envelope, the junctions of the windows with the walls, the deformation parts of the outer windows and doors, and the joints and vents that imprecisely sealed. The exhaust vents were found to be the most significant source of leakage among the tested typical air leakage places.

INFLUENCE OF WINDOW TYPE ON THE AIRTIGHTNESS OF RESIDENTIAL UNITS

Airtightness plays a significant role in the energy efficiency of buildings. In this paper, we investigated how varying the type of window affects the airtightness values of residential units. We studied three sets of residential units, each comprising two residential units with the same geometry and year of construction, varying only the installed window type and window-frame material. A brief explanation is included of the blower-door method, used in field-testing the airtightness of residential units. Replacing the old windows in the residential units with newer windows significantly improved the airtightness. To generalize these results, further research is needed with larger samples.

Application of neural networks in predicting airtightness of residential units

The paper describes the need to investigate airtightness of existing residential units in order to achieve adequate energy efficiency. There is a brief explanation of the blower door method used in field testing of airtightness in residential units. The mentioned method was used to create a database of airtightness test results obtained in situ at 58 residential units in the local area. The analysis of the results of these measurements indicates that there are four input parameters, which had been previously investigated and evaluated, that had a dominant effect on the test results. The examining of the possibility of successfully predicting airtightness was conducted by applying neural networks. The response results indicate that there is potential for successful prediction of airtightness, which was confirmed by independent validation through 20 additional measurements. In order to be able to generalize the results, further research needs to be conducted, using a bigger sample of measured data, and additional configurations of neural networks need to be examined.

Measured air tightness performance of residential buildings in North China and its influence on district space heating energy use

There is little known about air tightness performance of residential buildings in north China and its effect on district heating. Air tightness performance of two buildings in the cold zone of China, namely Hui’an building and Ruiguang building was measured by blower door method. Hui’an building has the average air change rate of 0.24h−1, and Ruiguang building has the value of 0.98h−1. The families located at the ends of the building have the worse air tightness performance than the families in the middle, while the performance of the family on the top floor is worse than those on the middle floor. Comparing with the foreign studies, the performance of Hui’an building is comparable with the similar buildings in Lithuania, UK, Russia and USA, but Ruiguang building has the worst performance among all these studies. Foreign standards have higher requirement, where the performance of Hui’an building can only meet the Netherlands’ standard, and falls behind the standards of Finland, Belgium, Denmark, Canada, USA and UK, and Ruiguang building cannot meet any of these standards. Simulation shows the total energy use of district heating is reduced by 12.6% when ACH of Ruiguang building is reduced from 0.98h−1 to 0.5h−1.

Blower door method and measurement technology in radon diagnosis

The health risk and dose calculations from exposure to indoor radon concentration are based on long-term measurements and ICRP recommendations. The results of radon concentration measurements predicate more about human activities instead of the radon infiltration into the building. It means that we are not able to compare the results for different types of buildings and to characterize the radon supplies independently on indoor human activities. In our research, we strive to find out a set of methods not depending on residential habits and weather conditions, characterizing the building construction as a radon barrier.

Results and conclusions of the Austrian radon mitigation project ‘SARAH’

The Austrian radon mitigation joint research project SARAH (supported by the Austrian Ministry of Economy and the Government of Upper Austria), a 2-year follow-up study of the Austrian National Radon Project (ÖNRAP), was started in 1996. The objectives of the research project were to find simple, cost-effective experimental methods for the characterisation of the radon situation in dwellings and to evaluate technically and economically the implementation of state of the art remedial actions for Austrian house types. After an intercomparison exercise of the assigned radon measuring instruments and detectors five houses were closely examined in regions with elevated radon levels in the federal state of Upper Austria. In this research work for the first time an extended Blower–Door method (which is conventionally used for determining the tightness of buildings) was successfully applied to radon diagnosis of buildings. In this paper the methods used for the radon diagnosis, the applied mitigation measures and the related technical and economical aspects are discussed. In conclusion of the results of this project a common strategy for solving the radon problem in Austria in the future is presented briefly.