Positive pressure effect on moisture performance in a school building

2019 ◽  
Vol 43 (2) ◽  
pp. 121-142
Author(s):  
Andrea Ferrantelli ◽  
Camilla Vornanen-Winqvist ◽  
Milla Mattila ◽  
Heidi Salonen ◽  
Jarek Kurnitski
Keyword(s):  
Air Quality ◽  
Moisture Content ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Moisture Transfer ◽  
Building Envelope ◽  
Positive Pressure ◽  
School Building ◽  
Negative Effects ◽  
Moisture Performance

Moisture excess in buildings constitutes a complex problem affecting indoor air quality, energy consumption and the lifetime of the building envelope. We investigate the effect on moisture transfer in structures as a positive pressure is applied inside the enclosure. It is found that, contrary to established belief, the positive pressure does not induce any negative effects on the structures’ moisture content in normally ventilated classrooms, even with high occupancy. Our case study consists of a school building in Finland, subject to temperature and relative humidity measurements after a small (5–7 Pa) positive pressure was realized through ventilation control. We first address analytically the moisture excess generated inside the classrooms for 14 days, using dynamical balance equations that account for both ventilation effects and occupants’ moisture release in the environment. It is found that the average moisture excess is very small, largely below 1 g/m3, even for ventilation rates that are half the design value. We also examine the moisture performance of the envelope, by addressing the moisture migration at upper and lower joints of the external walls for both measured and design values of the indoor absolute humidity (AH). A coupled numerical model of diffusion and convection shows that moisture accumulation in the envelope and the according stresses are negligible for any realistic AH values. This result is in agreement with field measurements at the school. In conclusion, it seems that applying a small overpressure in a well-ventilated school building during a standard service period resulted in no accumulation inside the external walls, even at high occupancy and with low ventilation. Remarkably, it slightly dried out the moisture content in structures under actual occupancy conditions. The positive pressure has accordingly no negative effects on moisture performance, and is capable to guarantee a good indoor air quality as well.

scholarly journals The effect of positive pressure on indoor air quality in a deeply renovated school building – a case study

2017 ◽  
Vol 132 ◽  
pp. 165-170 ◽  
Author(s):  
Camilla Vornanen-Winqvist ◽  
Sander Toomla ◽  
Kaiser Ahmed ◽  
Jarek Kurnitski ◽  
Raimo Mikkola ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Positive Pressure ◽  
School Building

scholarly journals Ventilation Positive Pressure Intervention Effect on Indoor Air Quality in a School Building with Moisture Problems

2018 ◽  
Vol 15 (2) ◽  
pp. 230 ◽  
Author(s):  
Camilla Vornanen-Winqvist ◽  
Kati Järvi ◽  
Sander Toomla ◽  
Kaiser Ahmed ◽  
Maria Andersson ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Positive Pressure ◽  
School Building ◽  
Intervention Effect

scholarly journals Determination of indoor air quality in collective living spaces utilizing Fuzzy logic analysis

2020 ◽  
Vol 19 (3) ◽  
pp. 288-300
Author(s):  
Ahmet Cosgun ◽  
Keyword(s):  
Air Pollution ◽  
Fuzzy Logic ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Environmental Protection Agency ◽  
Environmental Pollutants ◽  
The United States ◽  
Indoor Environments ◽  
Negative Effects

Individuals have to work in collective living spaces which might be indoor or outdoor areas. In indoor works, people spend approximately 90% of their time in a closed space. There are many parameters affecting indoor air quality. Among these, for indoor and outdoor, important parameters can be listed as carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO₂), particles, nitrogen oxides (NOx), various microorganisms, harmful allergens, and powders. Some health problems might emerge in people who stay in indoor environments for a long time. For instance, newborns and infants are more likely to stay indoors. It is the primary reason for occurring many acute and chronic diseases at an early age, as babies and children are more sensitive to environmental pollutants. Recently published studies, which report that appendicitis failures might be fatal and air pollution can increase the rate of these failures, are remarkable. On the other hand, there are many negative effects of polluted indoor air on human health such as attention deficit and excessive daytime sleepiness. Moreover, the negative effects of this kind of indoor air quality on human learning and perception can not be neglected. The researchers focusing on indoor air quality are conducting studies showing that air pollution has an effect on physical activity and neurological interaction in humans. Even though air pollutants in outdoor air content were evaluated with fuzzy logic method in many studies, there are quite few studies using the fuzzy approach for indoor air quality. In this study, through the standard formula developed by the United States Environmental Protection Agency (EPA), calculations were made using fuzzy logic in MATLAB utilizing air quality index. In the study, indoor air quality measurement parameters were evaluated with the “Mamdani” method used in fuzzy logic. In the study, the model suitable for the logic structure created with the fuzzy tool in MATLAB was analyzed with the help of Mamdani method, and the suitability of evaluating the indoor air quality with artificial intelligence was investigated. A set of suggestions has been made evaluating and criticizing the results

Comparative study on indoor air quality variation while burning different firewood species in Gatlang, Rasuwa, Nepal

2020 ◽  
Author(s):  
Anu Dahal ◽  
Indira Parajuli
Keyword(s):  
Air Pollution ◽  
Carbon Monoxide ◽  
Particulate Matter ◽  
Air Quality ◽  
Moisture Content ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Indoor Air Pollution ◽  
Pm 2.5 ◽  
Abies Spectabilis

Abstract Indoor Air Pollution (IAP) from smoky cooking fires causes deaths over 22,800 per year being the fourth leading cause of death in Nepal. The study aims to compare the pollution level particularly Carbon Monoxide (CO) and Particulate Matter (PM 2.5 ) in different firewood species. Two households one with ICS and TCS is selected purposively to monitor the concentration of pollutants in Ward no. 3 of Gatlang, Rasuwa, Nepal. IAP Meter based on Laser Sensor principle is used to monitor real time concentration of PM 2.5 and CO. 24 hours mean concentration of PM 2.5 and 8 hours mean average concentrations of CO are found to be above the WHO and National Indoor Air Quality Guidelines i.e. For ICS using household the concentration is found to be 155.26 µg/m 3 and 9 ppm respectively and household using TCS is found to be 385.12 µg/m 3 and 12.2 ppm). Both pollutants’ concentration is found less in Abies Spectabilis than other species. Positive correlation is found in both households along with moisture content, amount of firewood used, etc. This result suggests the use of Abies Spectabilis as it emits less emission as compared to other species as it has less moisture content that reduces the concentration of air pollution. Keywords : Carbon Monoxide 1 , Particulate Matter (PM 2.5 ) 2 , Indoor Air Pollution 3

Comparative Study On Indoor Air Quality Variation While Burning Differnet Firewood Species In Gatlang, Rasuwa, Nepal

2020 ◽  
Author(s):  
Anu Dahal ◽  
Indira Parajuli
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Moisture Content ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Indoor Air Pollution ◽  
Average Concentration ◽  
Pollution Level ◽  
Laser Sensor ◽  
Abies Spectabilis

Abstract Indoor Air Pollution (IAP) from smoky cooking fires causes deaths over 22,800 per year being the fourth leading cause of death in Nepal. The study aims to compare the pollution level particularly Carbon Monoxide (CO) and Particulate Matter (PM2.5) in different firewood species. Two households one with ICS and TCS is selected purposively to monitor the concentration of pollutants in Ward no. 3 of Gatlang, Rasuwa, Nepal. IAP Meter based on Laser Sensor principle is used to monitor real time concentration of PM2.5 and CO concentration. 24 hours mean concentration of PM2.5 and 8hours mean average concentration of CO are found to be above the WHO and National Indoor Air Quality Guidelines i.e. For ICS using household the concentration is found to be 155.26µg/m3 and 9ppm respectively and household using TCS is found to be 385.12µg/m3 and 12.2ppm). Both concentrations are found less in Abies Spectabilis than other species. Positive correlation is found in both households along with moisture content, amount of firewood used, etc. This result suggests the use of Abies Spectabilis as it emits less emission as compared to other species as it has less moisture content that reduces the concentration of air pollution.

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