Indoor air quality measurements and staff absentee data were collected from elementary schools in a Winnipeg school division. Data was collected measuring carbon dioxide, carbon monoxide, temperature, relative humidity, particulate matter, and in some schools, radon. It was found that nearly all schools were experiencing some measure of IAQ problems. The most common issues measured were low levels of relative humidity and high concentrations of carbon dioxide. No significant relationships between staff absenteeism and IAQ parameters were identified in Pearson product-moment correlations and multiple regression analyses. Survey results found that 96% of respondents found IAQ problems in the workplace, and 79% of respondents show ‘sick building syndrome’-like symptoms. Recommendations have been provided to improve IAQ and establish an IAQ management program in order to improve the indoor environment in the school division.

Indoor air quality measurements and staff absentee data were collected from elementary schools in a Winnipeg school division. Data was collected measuring carbon dioxide, carbon monoxide, temperature, relative humidity, particulate matter, and in some schools, radon. It was found that nearly all schools were experiencing some measure of IAQ problems. The most common issues measured were low levels of relative humidity and high concentrations of carbon dioxide. No significant relationships between staff absenteeism and IAQ parameters were identified in Pearson product-moment correlations and multiple regression analyses. Survey results found that 96% of respondents found IAQ problems in the workplace, and 79% of respondents show ‘sick building syndrome’-like symptoms. Recommendations have been provided to improve IAQ and establish an IAQ management program in order to improve the indoor environment in the school division.

This thesis is designed to introduce beginning and experienced heating, ventilation and air conditioning (HVAC) engineers to common indoor air quality (IAQ) problems and solutions. The bulk of the work is a literature review of common pollutants, pollutant sources, HVAC equipment and systems, and remediation techniques. Pollutants covered include fungi, bacteria, dust mites, viruses, biofilms, microbiological volatile organic compounds (MVOC?s), volatile organic compounds (VOC?s), carbon dioxide, ozone, and radon. The HVAC systems covered are ventilation, direct expansion (DX), desiccant dehumidification, and system filters. The remediation techniques discussed are proper hygiene and maintenance, increased ventilation, humidity control, and proper selection of building materials.

No description available.

<p>One of the most fundamental human needs is fresh air. It has been estimated that people spend comparatively much time in indoor premises. That creates an elevated need for high-quality ventilation systems in buildings. The ventilation airflow rate is recognised as the main parameter for measuring the indoor air quality. It has been shown that the ventilation airflow rates have effects on respiratory diseases, on “sick building syndrome” symptoms, on productivity and perceived air quality. Ventilation is necessary to remove indoor-generated pollutants by diluting these to an acceptable level. The choice of ventilation airflow rate is often based on norms or standards in which the airflow rate is determined based on epidemiological research and field or laboratory measurements. However, the determination of ventilation flow rate is far more complex. Indoor air quality in the occupied zone can be dependent of many factors such as outdoor air quality, airflow rate, indoor generation of pollutants, moisture content, thermal environment and how the air is supplied into the human occupied zone. One needs to acknowledge the importance of air distribution which clearly affects the comfort of occupants. To design a ventilation system which considers all aspects of room ventilation can only be achieved by computer modelling. The objective of this thesis is to investigate air diffusion, indoor air quality and comfort issues by CFD (computational fluid dynamics) modelling. The crucial part of the CFD modelling is to adopt BCs (boundary conditions) for a successful and accurate modelling procedure. Assessing the CFD simulations by validated BCs enabled constructing the ventilation system virtually and various system layouts were tested to meet given design criteria. In parallel, full-scale measurements were conducted to validate the diffuser models and the implemented simplified particle-settling model. Both the simulations and the measurements reveal the full complexity of air diffusion coupled with solid contaminants. The air supply method is an important factor for distribution of heat, air velocity and solid contaminants. The influence of air supply diffuser location, contaminant source location and air supply method was tested both numerically and by measurements to investigate the influence of different parameters on the efficiency of room ventilation. As example of this, the well-known displacement ventilation is not fully able to evacuate large 10 μm airborne particles from a room. Ventilation should control the conditions in the human breathing zone and therefore the ventilation efficiency is an important parameter. A properly designed ventilation system could use less fresh air to maintain an acceptable level of contaminant concentration in the human breathing zone. That is why complete mixing of air is not recommended as the ventilation efficiency is low and the necessary airflow rate is relatively high compared to other ventilation strategies. Especially buoyancy-driven airflows from heat sources are an important part of ventilation and should not be hampered by supply airflow from the diffusers. All the results revealed that CFD presently is the only reliable method for optimising a ventilation system considering the air diffusion and contaminant level in all locations of any kind of room. The last part of the thesis addresses the possibility to integrate the CFD modelling into a building design process where architectural space geometry, thermal simulations and diffuser BCs could be embedded into a normal building design project.</p>

This thesis describes development of low cost indoor air quality (IAQ) monitoring system for research. It describes data collection of various parameters concentration present in indoor air and sends data back to host PC for further processing. Thesis gives detailed information about hardware and software implementation of IAQ monitoring system. Also discussed are building wireless ZigBee network, creating user friendly graphical user interface (GUI) and analysis of obtained results in comparison with professional benchmark system to check system reliability. Throughputs obtained are efficient enough to use system as a reliable IAQ monitor.

One of the most fundamental human needs is fresh air. It has been estimated that people spend comparatively much time in indoor premises. That creates an elevated need for high-quality ventilation systems in buildings. The ventilation airflow rate is recognised as the main parameter for measuring the indoor air quality. It has been shown that the ventilation airflow rates have effects on respiratory diseases, on “sick building syndrome” symptoms, on productivity and perceived air quality. Ventilation is necessary to remove indoor-generated pollutants by diluting these to an acceptable level. The choice of ventilation airflow rate is often based on norms or standards in which the airflow rate is determined based on epidemiological research and field or laboratory measurements. However, the determination of ventilation flow rate is far more complex. Indoor air quality in the occupied zone can be dependent of many factors such as outdoor air quality, airflow rate, indoor generation of pollutants, moisture content, thermal environment and how the air is supplied into the human occupied zone. One needs to acknowledge the importance of air distribution which clearly affects the comfort of occupants. To design a ventilation system which considers all aspects of room ventilation can only be achieved by computer modelling. The objective of this thesis is to investigate air diffusion, indoor air quality and comfort issues by CFD (computational fluid dynamics) modelling. The crucial part of the CFD modelling is to adopt BCs (boundary conditions) for a successful and accurate modelling procedure. Assessing the CFD simulations by validated BCs enabled constructing the ventilation system virtually and various system layouts were tested to meet given design criteria. In parallel, full-scale measurements were conducted to validate the diffuser models and the implemented simplified particle-settling model. Both the simulations and the measurements reveal the full complexity of air diffusion coupled with solid contaminants. The air supply method is an important factor for distribution of heat, air velocity and solid contaminants. The influence of air supply diffuser location, contaminant source location and air supply method was tested both numerically and by measurements to investigate the influence of different parameters on the efficiency of room ventilation. As example of this, the well-known displacement ventilation is not fully able to evacuate large 10 μm airborne particles from a room. Ventilation should control the conditions in the human breathing zone and therefore the ventilation efficiency is an important parameter. A properly designed ventilation system could use less fresh air to maintain an acceptable level of contaminant concentration in the human breathing zone. That is why complete mixing of air is not recommended as the ventilation efficiency is low and the necessary airflow rate is relatively high compared to other ventilation strategies. Especially buoyancy-driven airflows from heat sources are an important part of ventilation and should not be hampered by supply airflow from the diffusers. All the results revealed that CFD presently is the only reliable method for optimising a ventilation system considering the air diffusion and contaminant level in all locations of any kind of room. The last part of the thesis addresses the possibility to integrate the CFD modelling into a building design process where architectural space geometry, thermal simulations and diffuser BCs could be embedded into a normal building design project. / QC 20101007

Airflow into, out of, and within buildings is fundamental to their design and operation as it can affect occupant health and comfort, building durability, and energy consumption. This thesis works to develop the understanding of airflow patterns and pressure regimes in high-rise multi-unit residential buildings which are both unique and complex due to the combination of their height, typical inclusion of operable windows, and compartmentalized layout. Specific attention is directed towards the performance of corridor pressurization based ventilation systems which are used pervasively within industry to ventilate and control contaminant transfer in these buildings. Airflow is caused by pressure differences which for buildings are created by the driving forces of wind, stack effect, and mechanical ventilation systems. These airflows are resisted by the air permeance (i.e. airtightness) of building elements including the exterior enclosure and interior compartmentalizing elements. Using an experimental program at a case study building, this thesis assesses the interaction of these driving forces of airflow with the physical building to create the airflow patterns for a typical high-rise multi-unit residential building. Perflourocarbon tracer (PFT) testing was performed to measure in-service airflows into and out of the suites. This testing found that the air change rates of upper suites are significantly higher than that of lower suites and that most suites receive small fractions of modern ventilation rates or are over ventilated. Airflow measurements of the supply of ventilation air to each corridor indicate that these low flow rates are in part due to leakage of air from the supply duct. The PFT testing also found that significant airflow occurred from the parking garage below the building into the occupied building spaces indicating significant potential for transfer of harmful air contaminants. The air permeance of the exterior enclosure and interior compartmentalizing elements were measured using neutralized fan pressurization and depressurization techniques and found to be within typical ranges. In particular this testing found that only 20% of the flow paths out of the corridor were to the adjacent suites through the suite entrance doors and that flows to the elevator shaft and stairwells could create a significant inefficiency in the ventilation system. A long-term monitoring program was implemented at the case study building primarily to monitor exterior environmental conditions including wind and exterior temperature and to correlate these with measured pressure differences. A strong correlation was found between building pressure and exterior temperature. Nearly 70% of the theoretical stack effect pressure was measured to act across the corridor to suite pressure boundary which creates a significant pressure differences to be overcome by the ventilation system, likely contributing to the uneven distribution of ventilation rates. Both wind and stack effect pressures were found to often be of similar or greater magnitude than mechanically induced pressure differences and thus can overwhelm the ventilation system. Overall, the corridor pressurization based ventilation system at the case study building does not effectively or efficiently ventilate the building and also does not provide sufficient control of air contaminants. As the case study building was found to be relatively representative of a typical multi-unit residential building, the findings from this building can be extended to many other buildings. Effective ventilation and airflow control in multi-unit residential buildings likely requires suite compartmentalization and direct supply of ventilation via ducted or in-suite systems.

<p>Indoor air quality in office buildings can impact the health, well-being, and productivity of occupants. In most buildings, occupants exhaled breath is the primary source of carbon dioxide (CO₂). Concentrations of indoor CO₂ are also strongly associated with the operational mode of the mechanical ventilation system. While CO2 is routinely monitored in indoor environments, there are few spatially-resolved real-time measurements of CO₂ throughout mechanical ventilation systems. Such measurements can provide insight into indoor- and outdoor-generated CO₂ dispersion throughout a building and between the building and the outdoor atmosphere. This thesis aims to investigate spatiotemporal variations in CO₂ concentrations and mass fluxes throughout a mechanical ventilation system of a living laboratory office in a LEED-certified building. The impact of human occupancy patterns and ventilation conditions of CO₂ concentrations and fluxes was evaluated. </p> <p>A four-month measurement campaign was conducted in one of the four living laboratory offices at the Ray W. Herrick Laboratories. The living laboratory offices feature precise control and monitoring of the mechanical ventilation system via an advanced building automation system. Various mechanical ventilation modes were implemented, such as variable outdoor air exchange rates (AERs) and recirculation ratios. A novel multi-location sampling manifold was used to measure CO₂ at eight locations throughout the ventilation system, such as across the outdoor, supply, and return air ducts. Office occupancy was measured via a chair-based temperature sensor array. Volumetric airflow rate data and CO₂ concentration data were used to estimate CO₂ mass fluxes through the ventilation system. The CO₂ mass flux for the outdoor and exhaust air was used to evaluate the net CO₂ transport from the office to the outdoor atmosphere. </p> <p>The measurements demonstrate that there exist significant spatiotemporal variations in CO₂ concentrations across the outdoor, supply, and return air ducts. CO₂ concentrations varied with human occupancy in the office and the outdoor AER of the mechanical ventilation system. Due to human-associated CO₂ emissions, the net CO₂ mass flux from the office to the outdoor environment was approximately 700 kg of CO₂ per year. Thus, occupied offices may represent an important, yet unrecognized, source of CO₂ to the urban atmosphere.</p>

The primary objective of ventilation in a building is to ensure that the Indoor Air Quality (IAQ), together with the heating system, keep the thermal climate at an acceptable level. Meaning the deployment of ventilation air at the appropriate temperature rate supplied to meet the thermal climate into the parts of the building where residents reside. In Sweden, the two most commonly used ventilation strategies are stack ventilation and forced extract ventilation. Both methods utilize exhaust openings in kitchens and sanitary areas, while fresh air is drawn from either permeable external walls or through inlets located near windows and as distant as possible from the exhaust openings (Manz &amp; Huber, 2000). Stack-effect ventilation, also known as buoyancy ventilation, utilizes convective forces. Thus, vertical interior openings such as stairways or atriums play an essential role in the distribution of air and its suitability. Utilizing additional building elements such as a chimney enhances the stack-effect ventilation by elevating the height of the “vertical core” of warm air within the structure. The disparity in density (the difference in temperature between hot and cold) increases as a result of the amplification of pressure disparities (Liu et al., 2010). Hence, larger differences in pressure between the inside and outside will result in an increased driving force for the stack effect by enhancing the convective currents. The principle operates by drawing cooler air from the exterior,generally from the bottom or sides of the building, into the building. The air is then gradually heated and ascends through the vertical core due to convective forces, before being ultimately discharged through the chimney (Savin &amp; Jardinier, 2009). The architectural proposal seeks to adhere to sustainable building development by employing deliberate steps that incorporate a combination of principles and strategies based on the theory of convection. In order to acquire knowledge and validation, an extensive investigation of case studies was carried out, with the works of Philippe Rahm serving as the fundamental basis for further development. Furthermore, a laboratory environment was established to conduct physical tests as well as virtual simulations (CFD) in order to gain deeper understanding and accuracy regarding the relationship between convective forces and geometry. The thesis set out to place a bet based on the notion of consciousness, in terms of implementation of chosen principles, using materials with low embodied carbon, and employing a strategic geometric relationship. This approach enabled the design of an architectural proposal that is both responsive and educative, while also addressing the existing knowledge gap between different professions.