Multi-unit Residential Buildings Research Articles

A Comprehensive Assessment of Technical Impacts and User Experience with Food Waste Grinders in Multiunit Residential Buildings

A Comprehensive Assessment of Technical Impacts and User Experience with Food Waste Grinders in Multiunit Residential Buildings

Study on the Smoke Control Performance of Air Curtains in Emergency Stairwells of Multi-Unit Residential Buildings

Recently, in high-rise buildings, pressurization systems have been installed in emergency stairwells to prevent the ingress of smoke. However, in older buildings, these stairwells often lack pressurization systems, while in buildings with fewer stories, such systems are not typically installed. This study conducts simulations and a hot smoke test to evaluate the performance of air curtains in blocking smoke and toxic gases in outdoor emergency stairwells where additional pressurization equipment cannot be installed. The simulation results showed that air curtains installed perpendicular to the floor were useful at preventing smoke ingress, and higher wind speeds increased their effectiveness. It is believed that air curtains can partially reduce smoke ingress in stairwells of older buildings or low-rise structures without pressurization systems, thereby ensuring fire safety.

Ensuring the resilience of multi-unit residential buildings (MURBs): a building information modeling (BIM)-based evaluation approach

ABSTRACT Residential infrastructure, particularly multi-unit residential buildings (MURBs), lacks sufficient attention to resilience. This oversight is attributed to the absence of specific guidelines for assessing MURBs’ resilience, with existing literature primarily concentrating on singular hazards. Additionally, current frameworks for resilience evaluation necessitate manual interpretation, leading to time and cost inefficiencies and potential human errors. The present study, therefore, developed a comprehensive framework and an automatic rule-based checking system on MURB resilience that can be utilized as a decision support system for practitioners. A literature review revealed 44 resilience indicators, categorized into four based on the general characteristics, i.e., technical, organizational, geographical positioning, and economic. The resilience indicators were benchmarked and defined as a building information modeling (BIM) ruleset. A case study was conducted to demonstrate the execution of the developed BIM ruleset using a MURB design. The proposed framework and rule-based checking system help ensure that MURBs comply with resilience requirements.

EVSE Effectiveness in Multi-Unit Residential Buildings Using Composite Optimization and Heuristic Search

The effectiveness of electric vehicle supply equipment (EVSE) is a very important factor in multi-unit residential buildings (MRBs) when planning to invest in an electric vehicle (EV). However, the expected benefits depend on not only technology but also need many non-functional requirements such as building facilities, electrical infrastructure, operating costs, and energy demand management of EVSE. We discuss the functional and non-functional constraints in utilizing EVSEs in MRBs and addresses them by constructing a composite optimization problem with a heuristic boundary selection. The proposed model urges the use of electrical safety codes –to mitigate the hazard risk– and promotes deploying a flexible and scalable energy management system (EMS) to schedule, reserve, and tune the charging sessions. This article provides an effective EMS for mitigating the energy demand growth caused by EV charging on MRBs, by finding the equilibrium number of EVSEs and their energy usage through a heuristic search. The proposed EMS is reinforced by embedding machine learning tools such as k-means, silhouette scoring, heuristic search, and autoregressive model to adjust the optimal operational state of EVSEs. We delineated the proposed framework and the outcomes using two case studies with real data. The results showed that more EVSEs can be utilized in MRBs and 100% EVs can be fully charged with a lower capital cost and no additional energy demand cost.

Machine learning-aided thermography for autonomous heat loss detection in buildings

Efficient inspection of heat loss from building façades is an active research area, driven by the need for improved auditing and monitoring solutions. Thermography is a valuable tool for identifying anomalous heat patterns. This paper presents a novel method for autonomous inspection of heat loss from building façades by combining thermal camera-based imaging, advanced deep learning with YOLOv7 for anomaly detection, and a mathematical model for heat flow quantification. The methodology achieved a mean average precision (mAP@0.5) of 0.770 for anomaly detection when tested on thermal data collected from a multi-unit residential building in an extremely cold climate. The highest heat loss measured at 1533.73 W was from the south façade, while the largest area of heat loss, covering 15.65 m2, was identified on the southeast façade. The study identified 28 regions of thermal anomaly on the building façades, and heat loss from these regions was quantified for inspection.

Size matters (at least for interior air flow pathways): The indoor air quality and energy implications of compartmentalization in multi-unit residential buildings

Interior building airtightness affects energy consumption and indoor air quality (IAQ) in multi-unit residential buildings (MURBs). Coupled CONTAM-EnergyPlus simulations were used to assess energy and IAQ performance for 4-storey and 20-storey MURBs for a Toronto, Canada climate. Different interior and exterior partition and door airtightness values and mechanical ventilation systems were assessed (including in-suite heat recovery ventilators (HRVs), pressurized corridor systems (PC) and direct-to-suite ducted systems (DTS). Three contaminants were emitted in all suite zones (CO2, NO2 and PM2.5). IAQ was assessed using annual average zone contaminant concentrations and the annual average fraction of suite concentration that originated from other zones, to quantify inter-zonal contaminant transport. Annual average suite fractional CO2 concentrations ranged from 3 to 35% for all airtightness and mechanical ventilation configurations; NO2 and PM2.5 ranges were 2–23% and 0–12%, respectively. HRV cases had the lowest space conditioning energy use intensities (EUI) and annual average suite fractional concentrations, compared to the respective PC and DTS cases. Interior partition and elevator/stairwell door airtightness had minimal effects in the 4-storey cases, but significantly reduced space conditioning EUI and fractional suite concentrations in the 20-storey cases, especially for cases with “loose” building envelope airtightness. Tightening interior/exterior partitions reduced inter-zonal contaminant transport, but increased source zone concentrations by reducing dilution. The results generally corroborate previous studies and highlight the importance of tightening both suite and shaft partitions, especially in tall buildings, and coupling compartmentalization with adequate mechanical ventilation.

COVID-19 outbreak at a residential apartment building in Northern Ontario, Canada.

In February 2021, a cluster of Beta variant (B.1.351) coronavirus disease 2019 (COVID-19) cases were identified in an apartment building located in Northern Ontario, Canada. Most cases had no known contact with each other. Objectives of this multi-component outbreak investigation were to better understand the social and environmental factors that facilitated the transmission of COVID-19 through this multi-unit residential building (MURB). A case-control study examined building-specific exposures and resident behaviours that may have increased the odds of being a case. A professional engineer assessed the building's heating, ventilation, and air-conditioning (HVAC) systems. Whole-genome sequencing and an in-depth genomic analysis were performed. Forty-five outbreak-confirmed cases were identified. From the case-control study, being on the upper floors (OR: 10.4; 95% CI: 1.63-66.9) and within three adjacent vertical lines (OR: 28.3; 3.57-225) were both significantly associated with being a case of COVID-19, after adjusting for age. There were no significant differences in reported behaviours, use of shared spaces, or precautions taken between cases and controls. An assessment of the building's ventilation found uncontrolled air leakage between apartment units. A single genomic cluster was identified, where most sequences were identical to one another. Findings from the multiple components of this investigation are suggestive of aerosol transmission between units.

Simulation and performance assessment of a heat pump coupled to a sub-slab thermal storage system

The paper explores the performance of a sub-slab ground heat exchanger, coupled to a heat pump, and the ability of the system to provide space conditioning and domestic hot water (DHW) for a multi-unit residential building (MURB) located in Ottawa, Ontario. The parametric analysis conducted to optimize the design of the building, as well as the sensitivity analysis performed to optimize the configuration of the sub-slab ground heat exchanger is also presented. According to the simulated results, the ground layer can store some of the rejected energy over medium term, without reducing the long-term performance of the heat pump. The annual energy consumption per dwelling unit (including heat pump, all auxiliary equipment, appliances, and lights) was estimated to be 28.4 GJ, significantly lower than the average annual energy consumption for a low-rise apartment in Canada (46.7 GJ per apartment). To assess the sensitivity of the system to environmental conditions, the simulation was conducted using the weather files for other five locations in Canada.

Association Between Clinical Remission of Infantile-Onset Allergic Rhinitis During the School-Age Period and the Type of Housing: A Longitudinal Population-Based Japanese Study

IntroductionThis study investigated the association between clinical remission of infantile-onset allergic rhinitis (AR) and the type of housing. MethodThis study used birth cohort data, focusing on 53,575 children born in 2001 in Japan. We examined whether infantile-onset AR remitted between the ages of 10 and 12 years. We classified the type of housing at the age of 2.5 years into four groups: detached house and multi-unit residential building with 1–2, 3–5, and ≥6 floors. Results4,352 children had infantile-onset AR between the ages of 1.5 and 4.5 years. The remission rate was 42.9%. Living in multi-unit residential buildings with 1–2 and ≥6 floors was associated with clinical remission of AR (adjusted risk ratio (aRR) = 1.10; 95% CI, 1.01–1.20; aRR = 1.31; 95% CI, 1.14–1.51. DiscussionThe type of housing may be associated with clinical remission of infantile-onset AR during the school-age period.

A novel method for quantifying risks to climate change events using conditional value at risk: a multi-unit residential building case study in London, Ontario

ABSTRACT Climate change may lead to more frequent and severe weather events, resulting in significant financial and human health impacts. This paper develops a risk metric using building performance simulation by associating thermal and incidental risks in buildings during power outages while considering multiple cold and hot events. Conditional Value at Risk (CVaR) is calculated using variations in outage events. According to the results, employing an integrated building design and a microgrid with photovoltaic panels that can be disconnected from the grid halves vulnerability related to ice storms and completely mitigates it for historical heatwave events. The variability study has revealed that a code-minimum design has eight times the CVaR of the as-built design. This novel methodology has the potential to inform future environmental, social, and corporate governance strategies and assist infrastructure operators in managing their risk exposure to future climate change events, considering various types of risks and multiple hazards.

Housing System, Challenges, and Perspectives The Case of Georgia

Expired or Dilapidated multi-apartment buildings are one of the main problems in post-Soviet countries. Although different countries have periodically developed different ways to solve the problem, it has not been possible to solve it until new reform, because the analysis of the current practice shows that the only way to solve the problem is to dismantle the dilapidated multi-apartment residential buildings and build new ones instead. 
 The present article discusses the history of the development of the housing system in Georgia, the preconditions of the housing crisis, the existing social programs in Tbilisi Municipality, and the reform aimed at the gradual replacement of dilapidated houses. The article focuses on the international experience related to housing fund management, including in the countries of the post-Soviet space. The scope of powers of the state, municipality, and owners, prerequisites for the replacement of damaged residential houses, and decision-making procedure are discussed. The replacement process, the general characteristics of the multi-unit residential buildings subject to replacement, and the challenges the social program faces are described.

Generative design of floor plans of multi-unit residential buildings based on consumer satisfaction and energy performance

Satisfying consumers is an important task in the design of residential floor plans. However, the design of residential floor plans with the aim of improving consumer satisfaction and energy performance has not been fully explored. Also, the preferences of different customer groups regarding customer satisfaction have not been studied. Traditional design and optimization methods still have limitations in terms of performance improvement, while performance-based generative design methods can explore the performance improvement potential of a larger range of solution spaces. Therefore, this study introduces a generative design framework that is grounded on optimizing energy performance and consumer satisfaction for multi-unit residential floor plans, which consists of four main processes: 1) Generation of floor plan schemes. 2) Evaluation of consumer satisfaction and energy performance of the generated schemes. 3) Running a multi-objective optimization to obtain optimal schemes. 4) The final floor plan scheme is determined by the decision maker. The proposed framework was employed in a real design case, and seven optimal solutions were obtained. Compared with the initial scheme, the maximum improvement in consumer satisfaction and energy performance was up to 38.78% and 11.18% respectively. The results also indicated that the preferences of different types of consumers differed significantly. Thus, different evaluation functions have been created to provide solutions with higher satisfaction levels targeting different types of consumers. As such, generative design and optimization of residential floor plans for specific types of consumers can be undertaken at an early design stage to improve consumer satisfaction and reduce energy consumption.

Energy Audits and Energy Modeling as a Tool towards Reducing Energy Consumption in Buildings: The Cases of Two Multi-Unit Residential Buildings (MURBs) in Toronto

This research is based on an energy audit of two multi-unit residential buildings (MURBs) located in Toronto, Canada. Energy consumption (gas and electricity) data were extracted from the energy bills of the two buildings for a consecutive period of three years. The data were then normalized to account for variations in weather conditions. Conclusions were drawn from correlation analyses between kWh, cooling degree days (CDDs), and heating degree days (HDDs), which were then compared to the energy consumption benchmarks of MURBs within the GTA. An energy simulation using e-Quest v.3.64 was performed, utilizing the advantages of the e-Quest building modeling tool to create a virtual 3D model of the audited buildings. A baseline model was constructed to reflect the actual buildings and was used to simulate the outcomes and calculate the projected energy savings from window replacements with a higher energy efficiency than the existing ones. The simulation results revealed that triple low-E glazing outperformed single- and double-glass windows, achieving reductions of 38% and 34% in gas consumption, respectively. The building envelope simulations showed that enhancing insulation reduced gas consumption by 4%, while an insulation upgrade demonstrated no discernible savings. Reducing the window area by 20% (north/south sides) led to a 6% decrease in gas consumption, while a 30% reduction resulted in approximately 9% of energy savings.

A Study on Verification of Waterproofing Method Properties for Performance Grading in Apartment Houses-Upper Slab of the Underground Structure

This study evaluates waterproofing methods for underground structures in multi-unit residential buildings. The objective is to select effective methods and establish performance ratings. Experimental assessments are conducted and scores are assigned for ranking. In this regard, waterproofing methods used in the upper slab of the top floor of multi-unit residential building underground structures were investigated, and they were categorized as composite waterproofing, sheet waterproofing, and membrane waterproofing methods. For performance evaluation purposes, experiments were conducted on qualified materials and scores were assigned to each test specimen, with a total score of 100 points. Based on the test results, scores for disqualified materials were deducted and, ultimately, the rankings of waterproofing materials and methods for the upper slab of the top floor of underground structures were determined based on the total aggregated scores. Subsequently, through proximity performance evaluation, the applied waterproofing methods were experimentally verified for defect issues based on the presence or absence of a proximity layer. This led to the ranking and performance grading of a total of 12 materials. The results confirmed the necessity of a proximity layer-dependent waterproofing method and highlighted the superiority of the composite waterproofing method with a proximity layer. Additionally, differences in installation methods and material properties between sheet and membrane waterproofing methods were identified, resulting in variations in performance grading.

Assessment of indoor exposure to outdoor environmental noise and effects on occupant comfort in multi-unit residential buildings

Outdoor environmental noise is a major source of annoyance in urban areas and exposure to it can increase the risk of severe health issues. Consequently, it has been the focus of research for decades. Even though people spend the majority of their time indoors, most studies use outdoor noise levels and do not include indoor noise measurements to estimate real exposure levels. This study conducted simultaneous indoor and outdoor noise measurements for 24 h in four multi-unit residential buildings to identify the levels and sources of outdoor noise heard indoors and quantify the effects of outdoor noise on indoor levels. The measurements were conducted in unoccupied suites that are most exposed to traffic and other outdoor noise sources. Surveys were administered following building occupancy to collect information regarding perceived acoustic comfort levels due to outdoor noise. The indoor LAeq,24h in three of the study buildings were above 40 dB(A) and exceeded WHO’s noise level limits. Regression analysis showed that outdoor noise only explains 14%–58% of the variability in indoor noise levels. This is mainly because of heating, ventilation, and air conditioning (HVAC) system noise which resulted in consistently high indoor noise levels despite variations in outdoor noise. Analysis of the survey showed a poor correlation between reported annoyance and measured noise levels. But annoyance strongly depended on other factors such as suite location and noise sensitivity. The findings show that outdoor noise measurements alone may not be good predictors of exposure levels and the effects of outdoor noise on occupants.

Exploring the Unit Spatial Layout Preference for Urban Multi-Unit Residential Buildings: A Survey in Beijing, China

Following the commodification reform of residential properties in China, multi-unit residential buildings (MURBs) have emerged as the most prevalent housing type owing to their high economic value and convenient infrastructure. In recent years, there has been an increasing concern regarding the potential negative impacts of MURBs on residents. To address this issue, in this study, a survey was conducted among 552 purchasers, and methods such as expert questionnaires, factor analysis, Kano two-dimensional quality, and analytic hierarchy process (AHP) were employed to evaluate the significance of 19 factors related to the quality of MURBs’ unit spatial layouts. An index model summarizing their utility was developed. The research findings indicated that spatial function held the greatest influence, followed by indoor environment, with spatial organization ranking last. Moreover, we analyzed the influence of preferences on satisfaction and the variations in preferences based on sociodemographic factors. The results aim to assist real estate developers and purchasers in evaluating the quality of housing spatial layouts, ultimately enhancing the overall quality and comfort of MURBs.

Housing preference shifting during COVID-19 pandemic in Indonesia

The COVID-19 pandemic has affected various aspects of people's lives, including housing. Research has argued that the economic impact of the pandemic includes stagnancy in the real estate markets. Similarly, Indonesian real-estate market players have reported declining demand for high-rise and dense multi-unit residential buildings in favor of landed houses during the pandemic. However, it has not yet included customers' perspective analysis, which raises a question of whether there has been a change in preferences for the types of housing caused by the pandemic. This paper aims to provide a scientific discourse on the topic using the explanatory quantitative method. The research sampled over 380 respondents from real-estate customers in 2020. The data were analyzed using binary logistic regression calculations. The result suggests increases in the need to control living space affect respondents' housing preferences. Factors that affect this phenomenon include the fear of meeting people and the fear of recessions; which are the direct impacts of the pandemic.

Empirical investigation of interzonal air leakage and airborne sound transmission correlation in multi-unit residential buildings

In the context of suite compartmentalization in multi-unit residential buildings, knowing the airtightness of individual pressure boundaries (e.g. floor, corridor wall, suite wall, etc.) is imperative for the diagnosis and remediation of issues such as regulating ventilation air delivery and managing pollutant transfer. However, conventional quantification methods, such as the pressure neutralization method, are cumbersome to complete. The feasibility of an acoustic testing approach, which leverages the relationship between increased air leakage rate and decreased airborne sound transmission loss was examined. Limited studies have explored this relationship in building enclosure elements, and no attempts were made to assess the correlation in interior partitions. In-situ measurements were conducted across twelve suite partition walls from three multi-unit residential buildings to obtain experimental correlations between the two parameters. The area-normalized air leakage rate at 50 Pa (q50) varied among specimens of the same composition, demonstrating the importance of air-sealing details for the overall partition airtightness. The variation in q50 was best reflected by the area-normalized sound transmission loss at 630 Hz; a non-linear model and the inclusion of air pressure differential information also improved the models’ accuracy. While the root-mean-square error of 0.56 L/s/m2 in q50 prediction suggests this acoustic approach needs further refinement to verify compliance with increasingly stringent compartmentalization targets, the current study demonstrates the application and potential benefits of the acoustic approach in a real-world context. Further data could improve the model so that it could be suitable for screening partitions with similar construction and in pre- and post-retrofit comparisons.

Comparing air sealing techniques for suite compartmentalization in a multi-unit residential building: Aerosolized sealant vs. conventional air sealing approaches

Recently, the use of aerosolized sealant has been proposed as an alternative to conventional (manual) air sealing approaches for suite compartmentalization in multi-unit residential buildings (MURBs). With this approach, aerosolized sealant is released into a positively pressurized zone; the resulting pressure differential across the zone partition draws the aerosolized product to the leakage paths where the particles accumulate until the leakage path is fully sealed. In theory, aerosolized sealants are more effective than conventional air sealing, as their installation does not require manual identification of leakage pathways. However, prior studies assessing the efficacy of aerosolized sealants have typically not included control groups, making it difficult to quantitatively compare aerosolized sealants against conventional techniques. This paper compares the performance of conventional air sealing approaches against aerosolized sealant (for suite compartmentalization) in a newly constructed MURB, in Toronto, Canada. Compartmentalization was assessed using unguarded, suite-level blower door tests. On average, suites sealed using aerosolized sealant were 27% tighter than those sealed using conventional approaches (q50 = 0.22L/s/m2 of suite surface area (0.04cfm50/ft2) vs. 0.30L/s/m2 (0.06cfm50/ft2), N = 5 suites per test group) – a statistically significant difference (t(8) = -2.01, p = 0.04). Guarded floor-level air leakage testing revealed that aerosolized sealant was most effective for leakage paths on vertical surfaces and had no impact on floor/ceiling airtightness. Apart from quantitative system performance, this paper discusses advantages and disadvantages of aerosolized sealants, based on lessons learned from the case study building. These results can help building designers and contractors weigh the relative benefits of using aerosolized sealants for suite compartmentalization.

Quantifying suite-level airtightness in newly constructed multi-unit residential buildings using guarded suite-level air leakage testing

Improving inter-zonal airtightness in multi-unit residential buildings (MURBs) has wide-ranging benefits including reduced odour/pollutant transfer, reduced sound transmission, and improved energy efficiency. The current metric used to assess inter-zonal airtightness in MURBs is the unguarded air leakage rate, which measures the air leakage through all interior and exterior suite boundaries. While this metric provides a general indication of overall suite airtightness, it provides no information on the location or distribution of leakage pathways across the individual suite partitions. Depending on the construction type(s) of suite partitions there may be variability in air leakage rates at the partition level, which is masked by the whole-suite metric. This makes it difficult to identify potential areas for improvement in design and construction practices.Guarded blower door testing was completed in 14 suites in six newly constructed/renovated MURBs, in Southern Ontario, Canada. Whole-suite air leakage rates for the sample were generally low, consistent with previous studies. Broken down by partition type, floor/ceiling and suite-to-suite walls exhibited similar levels of airtightness, with sample means of 0.36L/s/m2 and 0.32L/s/m2, respectively, at 50Pa (0.07cfm50/ft2 vs. 0.06cfm50/ft2). In contrast, the average suite-to-corridor wall air leakage rate was nearly eight times higher (2.46L/s/m2 (0.49cfm50/ft2)). The results highlight the need to develop targeted air sealing strategies to improve suite-to-corridor wall air leakage rates. Recommendations for improving inter-zonal air sealing practices in new construction are discussed. The measurements reported in this work will also help to improve building airflow simulations, which rely on partition-level air leakage metrics for model inputs.