Review of tracer gas-based methods for the characterization of natural ventilation performance: Comparative analysis of their accuracy

Remion, Gabriel; Moujalled, Bassam; Mankibi, Mohamed El

doi:10.1016/j.buildenv.2019.106180

Cited by 71 publications

(43 citation statements)

References 60 publications

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“…Results for six measurements are shown in Table 5. The slope of linear dependence of the corrected CO2 concentration increases with higher occupant density and ACH, but when CO2 gains are calculated from this slope similar values are obtained in all cases from 0.0043 to 0.0048 L/s, and agree with the theoretical value of Table 1 for young university students (18)(19)(20)(21)(22)(23)(24)(25) year old) with sedentary activity (M = 1.3 MET) with similar male and female contribution. The study of the method reproducibility in the workshop classroom, shows a high discrepancy between the results of both measurements (0.044 vs. 0.048 L/s).…”

Section: Resultssupporting

confidence: 83%

“…Thus a proper ventilation design as well as its regulation during operation process is crucial, with an optimal air flow that allows reasonable energy consumption in buildings also to established, in times of an adequate CO 2 concentration, as well as maintaining a proper microclimate for occupants of the building.There are different methods for estimation of building ventilation, including ACHs and air flow. A large part of them is based in the measurement of CO 2 produced by occupants as a tracer gas [21][22][23]. This type of methods needs the knowledge of CO 2 gain from people.…”

mentioning

confidence: 99%

“…There are different methods for estimation of building ventilation, including ACHs and air flow. A large part of them is based in the measurement of CO 2 produced by occupants as a tracer gas [21][22][23]. This type of methods needs the knowledge of CO 2 gain from people.…”

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confidence: 99%

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Carbon Dioxide Human Gains—A New Approach of the Estimation

Rodero

Krawczyk

2019

Sustainability

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Human health is dependent on the Indoor Air Quality (IAQ) of residential and public buildings, where people spend a substantial amount of time. Part of IAQ parameters, like temperature or humidity influence the thermal comfort of users, whereas too high carbon dioxide concentration (CO 2 ) could cause various complaints or diseases. In buildings like offices and schools, where we have a brush with a high density of users, the main source of CO 2 is simply people. The type of their activity brings higher or lower carbon dioxide gains, that must be taken into account to design and properly use room ventilation, allowing recommended CO 2 levels not to be exceeded. This paper presents an approach to marking human CO 2 generation off by using an experimental method. The method was verified based on measuring results of six test series conducted in different types of rooms at Bialystok University of Technology (Poland) during lectures, meetings, projects and laboratories. Carbon dioxide gains were comparable with an average value of 0.0045 L/s, which corresponds to theoretical CO 2 generation rates that are symptomatic of males and females, between 16 and 30 years old, with low physical activity.Sustainability 2019, 11, 7128 2 of 12 dioxide concentration, is not considered particularly dangerous as such its high level could result in a room occupants becoming drowsy, fatigued and with insufficient ability to concentrate. A review of the literature conducted by Johnsona et al., [8] showed that there was an association between low-level exposure to CO 2 beginning at 700 ppm and building-related symptoms, whereas respiratory symptoms were indicated in children in a case of indoor CO 2 concentrations higher than 1000 ppm. However it was not possible to eliminate other causes of health problems. As highlighted by Meciarova et al., [9], CO 2 is not considered a pollutant of concern, but as an indicator of how well other people-related pollutants are controlled-particularly odor-causing compounds. As underlined by Lu et al., [6], the concentration of CO 2 in office buildings is primarily dependent on occupant density and ventilation rates. It is worth noting that CO 2 concentration is often found above recommendations in buildings with high people density and insufficient ventilation, especially schools [10][11][12][13][14][15][16][17]. Problems with CO 2 concentration in residential buildings were discussed by Mainka et al., [18].Nowadays, the ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers) standard [19] recommends indoor CO 2 concentrations less than 700 ppm above the outdoor concentration, giving also a guideline of 1000 ppm. Thus, the CO 2 recommended level is significantly lower than several years ago. As analyzed by Persily et al., [20] in 1981 the CO 2 limit of 4500 mg/m 3 (2500 ppm) was proposed in an appendix, while in 1989 the value was decreased by 60% to 1800 mg/m 3 (1000 ppm) and such a level was maintained in the 1999 and 2001 versions of the Standard 62.Sufficiently high venti...

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Section: Resultssupporting

confidence: 83%

mentioning

confidence: 99%

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Carbon Dioxide Human Gains—A New Approach of the Estimation

Rodero

Krawczyk

2019

Sustainability

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“…Indeed, the CO 2 measurement uncertainty could represent a secondary contribution to the AER back-calculation through the eq. 7, in fact, the uncertainty of the exhaled CO 2 emission rate could mainly affect the AER uncertainties [73,74].…”

Section: Resultsmentioning

confidence: 99%

Ventilation procedures to minimize the airborne transmission of viruses at schools

Stabile

Pacitto

Mikszewski

et al. 2021

Preprint

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Reducing the transmission of SARS-CoV-2 through indoor air is the key challenge of the COVID-19 pandemic. Crowded indoor environments, such as schools, represent possible hotspots for virus transmission since the basic non-pharmaceutical mitigation measures applied so far (e.g. social distancing) do not eliminate the airborne transmission mode. There is widespread consensus that improved ventilation is needed to minimize the transmission potential of airborne viruses in schools, whether through mechanical systems or ad-hoc manual airing procedures in naturally ventilated buildings. However, there remains significant uncertainty surrounding exactly what ventilation rates are required, and how to best achieve these targets with limited time and resources. This paper uses a mass balance approach to quantify the ability of both mechanical ventilation and ad-hoc airing procedures to mitigate airborne transmission risk in the classroom environment. For naturally-ventilated classrooms, we propose a novel feedback control strategy using CO2 concentrations to continuously monitor and adjust the airing procedure. Our case studies show how such procedures can be applied in the real world to support the reopening of schools during the pandemic. Our results also show the inadequacy of relying on absolute CO2 concentration thresholds as the sole indicator of airborne transmission risk.

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“…While the various measurement techniques are shown to be reliable under controlled single zone conditions, parallel experiments under real test conditions are rarely reported. 26 Early reports on the comparison of various tracer gas are as follows. Claude-Alain and Foradini 27 proved the feasibility of determining the specific air flow rate from the decay of CO 2 concentration; however, the decay method would not apply to bedrooms with occupants.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on tracer gas method for building infiltration rate measurement

Men

Wang

Zou

2020

Building Services Engineering Research and Technology

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The use of occupant-exhaled CO2 as the tracer gas enables the actual indoor infiltration rate to be measured, but the number and location of measuring points have a great impact on the accuracy of the results. This paper compares the experimental results from two tracer gas measurement techniques, decay with SF6 and constant injection with CO2 (exhaled by occupant). The results show a deviation of –9.0 to 7.4% between these two methods. This paper compares the result of this study with previous ones, and it confirmed that the CO2 method is an effective technique to calculate the infiltration rate in a room with a certain air volume when one measuring point is provided, and this is more accurate with good mixing of the indoor air. The impact of the measurement duration and distribution of indoor air on the measurement accuracy are also analysed. It is found that an extended monitoring period can reduce the impact of indoor air distribution. In actual measurements in residential building, it is recommended to select the data after occupants have been in the room for half an hour and to take measurements over 1 h after that. Practical application: Accurate air change per hour (ACH) is beneficial to the study of building energy consumption and indoor air quality. This paper explores the effectiveness of CO2 method, which provides useful reference for the large sample measurements of infiltration rates in residential buildings.

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Review of tracer gas-based methods for the characterization of natural ventilation performance: Comparative analysis of their accuracy

Cited by 71 publications

References 60 publications

Carbon Dioxide Human Gains—A New Approach of the Estimation

Carbon Dioxide Human Gains—A New Approach of the Estimation

Ventilation procedures to minimize the airborne transmission of viruses at schools

Experimental study on tracer gas method for building infiltration rate measurement

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