scholarly journals Evaluating methods for estimating whole house air infiltration rates in summer: implications for overheating and indoor air quality

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ben M. Roberts ◽  
David Allinson ◽  
Kevin J. Lomas
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Infiltration Rate ◽  
Estimation Methods ◽  
Tracer Gas ◽  
Content Type ◽  
Infiltration Rates ◽  
Air Infiltration ◽  
Fan Pressurisation

PurposeAccurate values for infiltration rate are important to reliably estimate heat losses from buildings. Infiltration rate is rarely measured directly, and instead is usually estimated using algorithms or data from fan pressurisation tests. However, there is growing evidence that the commonly used methods for estimating infiltration rate are inaccurate in UK dwellings. Furthermore, most prior research was conducted during the winter season or relies on single measurements in each dwelling. Infiltration rates also affect the likelihood and severity of summertime overheating. The purpose of this work is to measure infiltration rates in summer, to compare this to different infiltration estimation methods, and to quantify the differences.Design/methodology/approachFifteen whole house tracer gas tests were undertaken in the same test house during spring and summer to measure the whole building infiltration rate. Eleven infiltration estimation methods were used to predict infiltration rate, and these were compared to the measured values. Most, but not all, infiltration estimation methods relied on data from fan pressurisation (blower door) tests. A further four tracer gas tests were also done with trickle vents open to allow for comment on indoor air quality, but not compared to infiltration estimation methods.FindingsThe eleven estimation methods predicted infiltration rates between 64 and 208% higher than measured. The ASHRAE Enhanced derived infiltration rate (0.41 ach) was closest to the measured value of 0.25 ach, but still significantly different. The infiltration rate predicted by the “divide-by-20” rule of thumb, which is commonly used in the UK, was second furthest from the measured value at 0.73 ach. Indoor air quality is likely to be unsatisfactory in summer when windows are closed, even if trickle vents are open.Practical implicationsThe findings have implications for those using dynamic thermal modelling to predict summertime overheating who, in the absence of a directly measured value for infiltration rate (i.e. by tracer gas), currently commonly use infiltration estimation methods such as the “divide-by-20” rule. Therefore, infiltration may be overestimated resulting in overheating risk and indoor air quality being incorrectly predicted.Originality/valueDirect measurement of air infiltration rate is rare, especially multiple tests in a single home. Past measurements have invariably focused on the winter heating season. This work is original in that the tracer gas technique used to measure infiltration rate many times in a single dwelling during the summer. This work is also original in that it quantifies both the infiltration rate and its variability, and compares these to values produced by eleven infiltration estimation methods.

Assessing ventilation strategies in a school with observed indoor air problems

Facilities ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ulrika Uotila ◽  
Arto Saari ◽  
Juha-Matti Kalevi Junnonen ◽  
Lari Eskola
Keyword(s):  
Decision Making ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Final Decision ◽  
Target Number ◽  
Content Type ◽  
Existing Building ◽  
Ventilation Strategies

Purpose Poor indoor air quality in schools is a worldwide challenge that poses health risks to pupils and teachers. A possible response to this problem is to modify ventilation. Therefore, the purpose of this paper is to pilot a process of generating alternatives for ventilation redesign, in an early project phase, for a school to be refurbished. Here, severe problems in indoor air quality have been found in the school. Design/methodology/approach Ventilation redesign is investigated in a case study of a school, in which four alternative ventilation strategies are generated and evaluated. The analysis is mainly based on the data gathered from project meetings, site visits and the documents provided by ventilation and condition assessment consultants. Findings Four potential strategies to redesign ventilation in the case school are provided for decision-making in refurbishment in the early project phase. Moreover, the research presents several features to be considered when planning the ventilation strategy of an existing school, including the risk of alterations in air pressure through structures; the target number of pupils in classrooms; implementing and operating costs; and the size of the space that ventilation equipment requires. Research limitations/implications As this study focusses on the early project phase, it provides viewpoints to assist decision-making, but the final decision requires still more accurate calculations and simulations. Originality/value This study demonstrates the decision-making process of ventilation redesign of a school with indoor air problems and provides a set of features to be considered. Hence, it may be beneficial for building owners and municipal authorities who are engaged in planning a refurbishment of an existing building.

Renovation in hospitals: a case study on the use of control cubes for local repairs in health-care facilities

2020 ◽  
Vol 18 (3) ◽  
pp. 247-257
Author(s):  
Ehsan Mousavi ◽  
Vivek Sharma ◽  
Dhaval Gajjar ◽  
Shervin Shoai Naini
Keyword(s):  
Health Care ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Health Care Facilities ◽  
Repair Work ◽  
Content Type ◽  
Care Facilities ◽  
Pathogenic Agents ◽  
The Impact

Purpose The purpose of this study is to evaluate the effectiveness of the control cubes for dust control in health-care facilities. Research shows that more than 80% of pathogenic agents in hospitals are spread into the air, where they either remain airborne or deposit on the surface. At the same time, renovation and repair activities, including regular maintenance, are a necessity in active health-care facilities and a multitude of studies have documented their impact on indoor air quality. The dust that is generated by construction activities may potentially carry pathogenic agents, varying from coarse particles (≤10 µm, PM10) to fine particles (≤2.5 µm, PM2.5), including airborne bacteria, and fungal spores linked to high patient mortality in immune-compromised patients. Design/methodology/approach This study measures the impact and effectiveness of one such preventative measure, namely, the control cube (CC), on air quality during renovation and repair. CC is a temporary structure, typically made from stainless steel, around the local repair zone to minimize the spread of dust and potential microorganisms. The current paper presents a comparative analysis to identify the effectiveness of a CC equipped with the high-efficiency particulate filtration (HEPA) filter in a hospital setting by simulating construction renovation and repair work. Findings A baseline was established to measure the effectiveness of CCs and the impact of negative pressure on the indoor air quality in a hospital during simulated renovation work. Results showed that CCs are very effective in minimizing the spread of dust due to construction activities in the hospital. However, it is imperative to ensure that the air inside the CC is cleaned via filtration. Originality/value CCs are very effective, and this paper investigates the best approach for facility managers to implement this strategy.

Coupled Computational Fluid Dynamics (CFD) and Artificial Neural Network (ANN) for Prediction of Traffic-related Air Pollution Infiltration Effects in Hong Kong

2020 ◽  
Author(s):  
Fritz Nieborowski
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Real Life ◽  
Infiltration Rate ◽  
Forced Ventilation ◽  
Real Life Data ◽  
Air Intake ◽  
Forced Air

<div> <p>Improper ventilation of buildings may lead to an accumulation of pollutants indoors. In the case of a room with forced air ventilation and external air intake like most centralized and some home air conditioning units, this study will show CFD simulations of various indoor air quality conditions based on different forced ventilation AC unit intake conditions like common in housing situations like Hong Kong. Especially when close to roadways or other external pollution sources, the positioning of the air intake shows up to have a high significance for the infiltration rate resulting as influence for the indoor air quality as previous research shows (e.g. Zheming Tong et al., 2016). The same is the case for a forced ventilation case like air conditioning units with outside air intake. Research like earlier referenced paper has not been conducted with higher buildings or forced air intake yet. Parametrized CFD-based air quality models with using OpenFoam will be employed to quantify the impact of the air intake location and rate in a 2-dimensional interface on the indoor air quality of a forced ventilated section of a building. The findings of the CFD simulation will be simplified as average indoor air pollution and other external factors. As an approach to predict the estimate indoor infiltration rate, an ANN (Artificial Neuronal Network) will be used, trained and validated with said data. The neural network is supposed to predict the pollutant intake based on fewer and as easier to obtain meteorological parameters and air pollution data. Finally, the ANN predictions of the models will be verified with real life data from other papers. Results will show that a major part of indoor pollutants may emerge indoors and cannot be neglected. In comparison with real life data, it seems the model lacks significant input to predict with high accuracy. </p> </div>

scholarly journals Indoor Air Quality Intervention in Schools; Effectiveness of a Portable HEPA Filter Deployment in Five Schools Impacted by Roadway and Aircraft Pollution Sources

2022 ◽  
Author(s):  
Nancy Carmona ◽  
Edmund Seto ◽  
Timothy Gould ◽  
Jeffry H. Shirai ◽  
Lisa Hayward ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ultrafine Particles ◽  
Wildfire Smoke ◽  
Infiltration Rates ◽  
Before And After ◽  
Study Team ◽  
Healthy Schools ◽  
The Impact

The Healthy Air, Healthy Schools Study was established in January 2020 to better understand the impact of ultrafine particles (UFP) on indoor air quality in communities surrounding Seattle-Tacoma (Sea-Tac) International Airport. The study team took multipollutant measurements indoor and outdoor air pollution at five participating school locations to infiltration indoors. The schools participating in this project were located within a 7-mile radius of Sea-Tac Airport and within 0.5 miles of an active flight path. Based on experimental measures in an unoccupied classroom, infiltration rates of a) Ultrafine particles of aircraft origin b) Ultrafine particles of traffic origin and c) Wildfire smoke or other outdoor pollutants were characterized before and after the introduction of a classroom based portable HEPA filter intervention. The portable HEPA cleaners were an effective short-term intervention to improve the air quality in classroom environments, reducing the ultrafine particles to approximately 1/10th of that measured outside. Before the HEPA filter deployment, approximately one-half of all outdoor UFPs were measured indoors. This study is unique in focusing on UFP in school settings and demonstrating through multivariate methods that the UFP measured in the classroom space is primarily of outdoor origin. Although existing research suggests that improvements to indoor air quality in homes can significantly improve asthma outcomes, further research is necessary to establish the benefit to student health and academic performance of improved air quality in schools.

scholarly journals Field study of infiltration rate and its influence on indoor air quality in an apartment

2017 ◽  
Vol 205 ◽  
pp. 3954-3961 ◽  
Author(s):  
Xionglei Cheng ◽  
Hao Zhang ◽  
Wuxuan Pan ◽  
Sumei Liu ◽  
Mingrui Zhang ◽  
...  
Keyword(s):  
Air Quality ◽  
Field Study ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Infiltration Rate

scholarly journals Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 220
Author(s):  
Ewa Zender-Świercz
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Legal Regulations ◽  
Work Efficiency ◽  
Existing Buildings ◽  
Outdoor Temperature ◽  
Tracer Gas ◽  
Pm 2.5 ◽  
Passive Houses

Poor indoor air quality affects the health of the occupants of a given structure or building. It reduces the effectiveness of learning and work efficiency. Among many pollutants, PM 2.5 and 10 dusts are extremely important. They can be eliminated using mechanical ventilation equipped with filters. Façade ventilation devices are used as a way to improve indoor air quality (IAQ) in existing buildings. For their analysis, researchers used carbon dioxide as a tracer gas. They have shown that façade ventilation devices are an effective way to improve IAQ, but require further analysis due to the sensitivity of façade ventilation devices to the effects of wind and outdoor temperature. In addition, legal regulations in some countries require verification in order to enable the use of this type of solution as a way to improve IAQ in an era characterised by the effort to transform buildings into passive houses (standard for energy efficiency in a building).

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