Determination of optimal ventilation rates in educational environment in terms of radon dosimetry

Dovjak, Mateja; Virant, Barbara; Krainer, Aleš; Zavrl, Marjana Šijanec; Vaupotič, Janja

doi:10.1016/j.ijheh.2021.113742

Cited by 12 publications

(12 citation statements)

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“…The simultaneous analysis of measured and simulated 222 Rn and CO 2 data highlights the benefits in data evaluations compared to studies of either 222 Rn or CO 2 , as in our previous work [10,11,26]. However, the most beneficial evaluation was the transient analysis on measured and simulated 222 Rn and CO 2 datasets, which we used for the first time.…”

Section: Discussionmentioning

confidence: 83%

“… Measured data in indoor air: radon concentration C Rn-in [Bq m −3 ], carbon dioxide concentration

[ppm], temperature T in [°C], and relative humidity RH in [%]. Default data: the radon generation rate [Bq h −1 ] was determined for every hour according to the methodology defined in Dovjak et al [ 26 ]. The CO 2 metabolic emission rate is 0.0027 dm 3 s −1 during sleeping and 0.0038 dm 3 s −1 during light activity [ 56 ].…”

Section: Methodsmentioning

confidence: 99%

“…The DVR can be determined as the amount of fresh air: (i) per floor area; (ii) per room volume; (iii) per occupant; and (iv) for a specific contaminant. The final selection of the DVR is, therefore, often left to the designer, who, intending to achieve the lowest possible ventilation heat losses, favours lower DVR values [ 26 ]. Persley [ 27 ] highlighted the problem that many practitioners and researchers claim a building has good IAQ because it complies with the 1000 ppm CO 2 limit set in the standard.…”

Section: Introductionmentioning

confidence: 99%

“…The tightening of the building energy efficiency requirements, especially after 2010 [ 29 , 30 ], has been reflected in increased building airtightness as well as decreased DVRs in several ongoing construction projects [ 26 ]. As a result, such engineering measures might be related to a deterioration in indoor environmental quality.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, such engineering measures might be related to a deterioration in indoor environmental quality. IAQ in energy-efficient residential and non-residential buildings has already been analysed by many authors [ 26 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. The problem of increased indoor radon concentrations in renovated residential buildings has also been highlighted in several studies [ 32 , 35 , 36 , 37 ].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Ventilation Efficiency as Simultaneous Control of Radon and Carbon Dioxide Levels in Indoor Air Applying Transient Modelling

Dovjak

Vene

Vaupotič

2022

IJERPH

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The impact of ventilation efficiency on radon (222Rn) and carbon dioxide (CO2) concentrations in the indoor air of a residential building was studied by applying transient data analysis within the CONTAM 3.4 program. Continuous measurements of 222Rn and CO2 concentrations, together with basic meteorological parameters, were carried out in an apartment (floor area about 27 m2) located in Ljubljana, Slovenia. Throughout the experiment (October 3–15), frequent ventilation (several times per day), poor ventilation (once to twice per day) and no ventilation scenarios were applied, and the exact ventilation and occupancy schedule were recorded. Based on the measurements, a transient simulation of 222Rn and CO2 concentrations was performed for six sets of scenarios, where the design ventilation rate (DVR) varied based on the ventilation requirements and recommendations. On the days of frequent ventilation, a moderate correlation between the measured and simulated concentrations (r = 0.62 for 222Rn, r = 0.55 for CO2) was found. The results of the simulation indicated the following optimal DVRs: (i) 36.6 m3 h−1 (0.5 air changes per hour, ACH) to ensure a CO2 concentration below 1000 ppm and a 222Rn concentration below 100 Bq m−3; and (ii) 46.9 m3 h−1 (0.7 ACH) to ensure a CO2 concentration below 800 ppm. These levels are the most compatible with the 5C_Cat I (category I of indoor environmental quality, defined by EN 16798-1:2019) scenario, which resulted in concentrations of 656 ± 121 ppm for CO2 and 57 ± 13 Bq m−3 for 222Rn. The approach presented is applicable to various types of residential buildings with high overcrowding rates, where a sufficient amount of air volume to achieve category I indoor environmental quality has to be provided. Lower CO2 and 222Rn concentrations indoors minimise health risk, which is especially important for protecting sensitive and fragile occupants.

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Section: Discussionmentioning

confidence: 83%

“… Measured data in indoor air: radon concentration C Rn-in [Bq m −3 ], carbon dioxide concentration

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%