Assessment of the air change rate of airtight buildings under natural conditions using the tracer gas technique. Comparison with numerical modelling

In this study, the results of an airflow investigation conducted on 7 June 2015 as part of a series of epidemiologic investigations at Pyeongtaek St. Mary’s Hospital, South Korea, were investigated. The study involved 38 individuals who were infected directly and indirectly with Middle East Respiratory Syndrome (MERS), by a super-spreader patient. Tracer gas experiments conducted on the eighth floor, where the initial patient was hospitalized, confirmed that the tracer gas spread to adjacent patient rooms and rooms across corridors. In particular, the experiment with an external wind direction and speed similar to those during the hospitalization of the initial patient revealed that the air change rate was 17–20 air changes per hour (ACH), with air introduced through the window in the room of the infected patient (room 8104). The tracer gas concentration of room 8110, which was the farthest room, was 7.56% of room 8104, indicating that a high concentration of gas has spread from room 8104 to rooms across the corridor. In contrast, the tracer gas was barely detected in a maternity ward to the south of room 8104, where there was no secondary infected patient. Moreover, MERS is known to spread mainly by droplets through close contact, but long-distance dispersion is probable in certain environments, such as that of a super-spreader patient hospitalized in a room without ventilation, hospitals with a central corridor type, and indoor airflow dispersion due to external wind.

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Experimental study on natural ventilation of dwellings Estimation of air change rate by tracer gas method with wind tunnel experiment

Wind Engineers JAWE ◽

10.5359/jawe.1987.33_1 ◽

1987 ◽

Vol 1987 (33) ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Shuzo MURAKAMI ◽

Shin-ichi AKABAYASHI

Keyword(s):

Experimental Study ◽

Wind Tunnel ◽

Natural Ventilation ◽

Wind Tunnel Experiment ◽

Tracer Gas ◽

Change Rate ◽

Air Change Rate

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A Discussion Regarding the Measurement of Ventilation Rates Using Tracer Gas and Decay Technique

Infrastructures ◽

10.3390/infrastructures5100085 ◽

2020 ◽

Vol 5 (10) ◽

pp. 85

Author(s):

Ricardo M. S. F. Almeida ◽

Eva Barreira ◽

Pedro Moreira

Keyword(s):

Cross Contamination ◽

Single Family ◽

Outdoor Temperature ◽

Time Dependency ◽

Tracer Gas ◽

Large Variability ◽

Change Rate ◽

Air Change Rate ◽

Ventilation Rates

The measurement of ventilation rates is crucial in understanding buildings’ performances, but can be a rather complex task due to the time-dependency of wind and buoyancy forces, which are responsible for the pressure differences that induce air movement across the envelope. Thus, assessing air change rate through one-time measurements during brief periods of time may not be a reliable indicator. In this paper, the variability in the measurement of ventilation rates using the decay technique was evaluated. To that end, two compartments of a typical single-family detached dwelling were selected as a case study and 132 tests were performed, considering two different boundary conditions (door closed and door open). This work allowed the large variability of the results to be highlighted, as the coefficient of variation ranged from 20% to 64%. Wind speed had a key effect on the results, especially because during the measurements indoor–outdoor temperature differences were not so significant. The possibility of using occupant-generated carbon dioxide as tracer gas was also analyzed, but problems of cross-contamination were identified.

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Stable carbon isotope labelled carbon dioxide as tracer gas for air change rate measurement in a ventilated single zone

Building and Environment ◽

10.1016/j.buildenv.2017.01.021 ◽

2017 ◽

Vol 115 ◽

pp. 173-181 ◽

Cited By ~ 3

Author(s):

K.E. Anders Ohlsson ◽

Bin Yang ◽

Alf Ekblad ◽

Christoffer Boman ◽

Robin Nyström ◽

...

Keyword(s):

Carbon Dioxide ◽

Carbon Isotope ◽

Stable Carbon Isotope ◽

Rate Measurement ◽

Stable Carbon ◽

Tracer Gas ◽

Change Rate ◽

Air Change Rate

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Developing a new passive tracer gas test for air change rate measurement

International Journal of Ventilation ◽

10.1080/14733315.2020.1777660 ◽

2020 ◽

pp. 1-11

Author(s):

Sarah L. Paralovo ◽

Maarten Spruyt ◽

Joris Lauwers ◽

Rudi Swinnen ◽

Borislav Lazarov ◽

...

Keyword(s):

Passive Tracer ◽

Rate Measurement ◽

Tracer Gas ◽

Change Rate ◽

Air Change Rate

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Assessing the variability of the air change rate through tracer gas measurements

Energy Procedia ◽

10.1016/j.egypro.2017.10.013 ◽

2017 ◽

Vol 132 ◽

pp. 831-836 ◽

Cited By ~ 1

Author(s):

Ricardo M.S.F. Almeida ◽

Eva Barreira ◽

Pedro Moreira

Keyword(s):

Tracer Gas ◽

Change Rate ◽

Air Change Rate ◽

Gas Measurements

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Assessment of exposure risk from hidden fungal growth by measurements of air change rates in construction cavities and living areas

Journal of Building Physics ◽

10.1177/1744259117704386 ◽

2017 ◽

Vol 41 (3) ◽

pp. 209-224 ◽

Cited By ~ 1

Author(s):

Sofie M Knudsen ◽

Eva B Møller ◽

Lars Gunnarsen

Keyword(s):

Field Study ◽

Fungal Growth ◽

Building Envelope ◽

Exposure Risk ◽

Tracer Gas ◽

Change Rate ◽

Health Symptoms ◽

Air Change Rate ◽

Gaseous Pollution ◽

Growth Assessment

The transfer of particulate and gaseous pollution from hidden fungi growing on non-visible surfaces within the building envelope to occupied rooms is limited by the separating structure. Yet, growth, even in sealed construction cavities, is known to cause annoying smells and other more adverse health symptoms among the building occupants. This study analyses limitations of air change rate measurements in inaccessible construction cavities as well as analyses of the air exchange between living areas and accessible cavities such as crawl spaces and attics. It was necessary to invent a field study technique to use the tracer gas decay method in small and inaccessible cavities. This technique allowed further investigation on the exposure risk from hidden fungal growth. Assessment of the air transfer between crawl spaces and living areas indicate that the tightness of separating structure has an influence on the exposure risk.

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Analysis of Calculation Errors for Single-zone and Multi-Zone Natural Ventilation model in Residential Building

E3S Web of Conferences ◽

10.1051/e3sconf/20185303034 ◽

2018 ◽

Vol 53 ◽

pp. 03034

Author(s):

Zheqi Xuan ◽

Xiaohong Zheng ◽

Zhenni Shi

Keyword(s):

Thermal Expansion ◽

Thermal Expansion Coefficient ◽

Rainy Season ◽

Natural Ventilation ◽

Residential Building ◽

Zone Model ◽

Tracer Gas ◽

Change Rate ◽

Air Change Rate ◽

Different Seasons

The typical residential building in Changzhou City, Jiangsu Province was selected for natural ventilation measurement during the transitional season, the plum rainy season, summer and winter. In this paper, SF6 is used as the tracer gas, and tracer gas decay method was selected to obtain the air change rate in the room under each measuring condition. EnergyPlus(EP) was used to calculate the single-zone and multizone air change rate which can be compared with the measured values respectively. It was found that the calculated values of single-zone model were generally small and the errors were large. And the calculated values of multi-zone model have a significant reduction in error after considering the equivalent infiltration area. In addition, the effective infiltration area will be different due to the existence of the thermal expansion coefficient for different seasons.

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