Multi-unit Residential Buildings Research Articles

Impact of Balance between Productivities on Repetitive Construction Projects

Fast delivery of construction projects provides more value to project owners. Batch production, which is production not in single pieces, but in batches, is a common approach in repetitive construction projects such as multi-unit residential building construction projects. In batch production, the use of a small batch size allows the early start of subsequent activities, and thus can lead to early completion of projects. In addition to batch size, balance between productivities in construction activities can affect project duration. However, the impact of the balance between productivities with regard to their order on project duration has not been studied. The main goal of this study is to test a hypothesis, which is that the order of construction activities’ unbalanced productivities affects the amount of time reduction that can be achieved by using a small batch size. A computer-based simulation model was developed, and five different cases were simulated to test the hypothesis. The conclusion of the simulation result is that the order of productivities does not affect the time reduction achieved by using a small batch size. It is expected that the findings of this study can help general contractors make decisions in terms of batch size.

Correlating energy consumption with multi-unit residential building characteristics in the city of Toronto

Multi-unit residential buildings (MURBs) in City of Toronto, Canada, contain more than half of the dwellings in the City and are responsible for a significant proportion of the greenhouse gas (GHG) emissions associated with building energy-use in the residential sector. To efficiently reduce the impact of this sector, MURBs with the highest energy intensity need to be identified. Accordingly, this study examined correlations between building characteristics and energy use. A wide range of energy intensities were revealed and it was found that typology-specific energy-use trends could not be established. The energy intensity variability was attributed to differences in building operation and it was suggested that many buildings can realize improved energy performance by changing operating procedures. The building characteristics exhibiting the strongest correlations with energy use were fenestration ratio and boiler efficiency. However, the need for more uniform and complete building characteristic and energy use data was identified. This study concludes with recommendations to improve the quantity and quality of MURB energy-use data and building characteristics so that researchers can develop a more accurate and complete picture of the MURB energy-use in Toronto.

Impact of balcony thermal bridges on the overall thermal performance of multi-unit residential buildings: A case study

The presence of thermal bridges in building envelopes influences the energy consumption, durability of the building envelopes, and the thermal comfort of occupants. Many existing and newly constructed multi-unit residential buildings (MURBs) in Canada have considerable thermal bridges such as balcony slab. Through 2D heat transfer and whole building energy simulations the impact of introducing a balcony thermal break on the overall heat transmittance, floor surface temperature distribution, and the total heating and cooling energy consumption is evaluated for a typical high-rise condominium building under various design scenarios. The results show that with the introduction of balcony thermal break, the overall heat transfer at balcony slab is significantly reduced and the interior floor surface temperature is greatly increased under typical winter design conditions for Toronto. The impact on the overall U-value of the building envelopes is improved by 9–18% depending on the thermal performance of the above and below balcony components. Whole building energy simulations show that reducing the heat transfer through balcony slabs, the space heating energy consumption may be reduced by 5–13% and space cooling energy consumption by less than 1%.

Application of Trigeneration to a Multi-Unit Residential Building in Canada

Application of Trigeneration to a Multi-Unit Residential Building in Canada

Secondhand smoke transfer and reductions by air sealing and ventilation in multiunit buildings: PFT and nicotine verification

Surveys suggest that transfer of secondhand smoke (SHS) between units in multiunit residential buildings is common, but measured data are rare. This study was undertaken to quantify bulk air transfer between units and document transfer of SHS species before and after treatments that sealed boundaries between units and provided a minimum amount of continuous exhaust ventilation of each unit. Six buildings in Minnesota were studied. Treatments were performed in clusters of up to eight units in each building, including zero to two units occupied by smokers. Bulk air transfer was quantified through passive perfluorocarbon tracer (PFT) gas tests. SHS transfer was evaluated using passive nicotine sampling. The median fraction of air entering a unit that came from other units tagged with PFTs ranged from 0.021 in a new condominium building to 0.353 in a 1930s duplex, with an overall median of 0.041. Treatments provided a median decrease of 29% in the fraction of transferred air and reduced PFT concentrations by about 40%, because of increased ventilation of both source and target apartments. Nicotine was transferred at only one-sixth the rate of PFTs. Involuntary exposure to SHS can be reduced but not eliminated by modifying existing, occupied multiunit buildings. Recent studies of secondhand smoke exposure in multiunit housing indicate transmission of SHS constituents from smokers' units to those occupied by nonsmokers. A straightforward solution for this problem is to eliminate air leakage transfer between these units. This study describes a 2-year investigation of air sealing and ventilation improvements in six multiunit buildings located in a heating-dominated climate region of the US. The results quantify the reduction in interunit transfer of air between smokers' and nonsmokers' units. While it is possible to reduce the transfer when done with care, it is extremely difficult to eliminate these flows unless the buildings are vacated and extensively rebuilt. Eliminating air leakage between smokers' and nonsmokers' units is not a practical means of solving SHS transmission in an existing building.

Rainwater tanks in multi-unit buildings: A case study for three Australian cities

Rainwater tanks have become popular in large Australian cities due to water shortage and greater public awareness towards sustainable urban development. Rainwater harvesting in multi-unit buildings in Australia is less common. This paper investigates the water savings potential of rainwater tanks fitted in multi-unit residential buildings in three cities of Australia: Sydney, Newcastle and Wollongong. It is found that for multi-unit buildings, a larger tank size is more appropriate to maximise water savings. It is also found that rainwater tank of appropriate size in a multi-unit building can provide significant mains water savings even in dry years. A prediction equation is developed which can be used to estimate average annual water savings from having a rainwater tank in a multi-unit building in these three Australian cities.

Wood Porch Design and Construction Issues

A porch structure, as discussed in this paper, refers to a structural system made up of platforms and stairs intended as a means to provide an alternate access to a multi-unit residential building. Although usually located in the back of a building, a porch could be located on any side, including in the front. Most common porches in Chicago are wood structures. However, steel and masonry porches are also prevalent. While most existing porches have performed reasonably well, the focus of new design requirements is to enhance safety by increasing the live load capacity of porches, and by adhering to structural details that provide maximum efficiency needed to transfer loads from floor to joists, girders, and columns down to the foundation and the ground. The main purpose of this narrative is to review these requirements and provide a forum for further discussions within the structural engineering community on porch design and construction issues. The discussions presented in this narrative focus on wood porches.

Regeneration of Public Residential Buildings for Rent in Japan

In Japan, various government authorities and public housing corporations built a huge number of dwellings for rent to reconstruct war-damaged cities and to accommodate the high concentrations of population in urban areas in the mass-housing era between 1955 and 1973. Approximately 40% of all public residential buildings for rent in Japan were constructed in the latter mass-housing era (1965-1973). These are four- or five-story reinforced concrete buildings whose building frames are sufficiently strong to withstand several decades' more use but whose interior finishings and functional systems are deteriorating. Although these houses were originally designed for nuclear families, they are now considered too small to accommodate more than three residents. There is growing demand for renovation of deteriorating public residential buildings for rent. Dwelling units of such deteriorating buildings are often enlarged by constructing extensions or by removing sections of existing partition walls and installing new partition walls. In recent years, several local authorities have started to add new elevator towers to residential buildings for the increasing number of aged residents. We have studied these regeneration projects in detail by conducting questionnaires at 60 public housing corporations and hearing investigations at 6 corporations. This paper describes the actual status of the regeneration of deteriorating public multi-unit residential buildings for rent in Japan.

Development of Thermodynamic, Geometric, and Economic Models for Use in the Optimal Synthesis/Design of a PEM Fuel Cell Cogeneration System for Multi-Unit Residential Applications

Thermodynamic, geometric, and economic models are developed for a proton exchange membrane (PEM) fuel cell system for use in cogeneration applications in multi-unit residential buildings. The models describe the operation and cost of the fuel processing sub-system and the fuel cell stack sub-system. The thermodynamic model reflects the operation of the chemical reactors, heat exchangers, mixers, compressors, expanders, and stack that comprise the PEMFC system. Geometric models describe the performance of a system component based on its size (e.g., heat exchanger surface area), and, thus, relate the performance at off-design conditions to the component sizes chosen at the design condition. Economic models are based on data from the literature and address the cost of system components including the fuel processor, the fuel cell materials, the stack assembly cost, the fuel cost, etc. As demonstrated in a forthcoming paper, these models can be used in conjunction with optimization techniques based on decomposition to determine the optimal synthesis and design of a fuel cell system. Results obtained using the models show that a PEMFC cogeneration system is most economical for a relatively large cluster of residences (i.e. 50) and for manufacturing volumes in excess of 1500 units per year. The analysis also determines the various system performance parameters including an electrical efficiency of 39% and a cogeneration efficiency of 72% at the synthesis/design point.

集合住宅におけるインフィル分離工事の施工特性(建築計画)

Multi-unit residential building based on the Open Building concept is called "S/I house" in Japan, and the number of S/I house construction is on the increase. On the other hand, the demand of infill refurbishment of existing buildings, which was constructed in mass-housing era, is also increasing. Field observations of infill refurbishment of three dwelling units in existing S/I building which had their own infill systems in each were conducted, and construction efficiency and construction process were discussed. It revealed their characteristics and problems in case of individual infill refurbishment, which differ from newly infill construction in various respects.

3D Computer modelling and human response

Current research within the Centre for Environmental Safety and Risk Engineering (CESARE) at Victoria University of Technology is focused on the issues of fire safety in multi-unit residential buildings. The level of fire safety performance in buildings is predicted using the CESARE-Risk System Model that comprises a number of submodels. One of these is the Human Response Model which is used to predict the response of occupants to different cues prior to evacuation from individual apartment. Reliable information on the probability of responses by occupants in the early period of an emergency, and the time taken to respond, are both essential as input to the Human Response Model. Existing data collection via detailed interviews with occupants who have experienved an actual fire is time consuming and is limited to the relatively few fires that occur in apartment buildings. To increase the reliability of data and to provide an alterantive means for collecting data on human behaviour in fire emergencies, a computer graphics model has been developed to simulate the response of occupants. A human responses database system has been developed, combining the simulation model with an interactive database management system. This paper presents the computer simulation model and describes the human response database system used for recording participants responses. Copyright © 1999 John Wiley & Sons, Ltd.

3D Computer modelling and human response

Current research within the Centre for Environmental Safety and Risk Engineering (CESARE) at Victoria University of Technology is focused on the issues of fire safety in multi-unit residential buildings. The level of fire safety performance in buildings is predicted using the CESARE-Risk System Model that comprises a number of submodels. One of these is the Human Response Model which is used to predict the response of occupants to different cues prior to evacuation from individual apartment. Reliable information on the probability of responses by occupants in the early period of an emergency, and the time taken to respond, are both essential as input to the Human Response Model. Existing data collection via detailed interviews with occupants who have experienved an actual fire is time consuming and is limited to the relatively few fires that occur in apartment buildings. To increase the reliability of data and to provide an alterantive means for collecting data on human behaviour in fire emergencies, a computer graphics model has been developed to simulate the response of occupants. A human responses database system has been developed, combining the simulation model with an interactive database management system. This paper presents the computer simulation model and describes the human response database system used for recording participants responses. Copyright © 1999 John Wiley & Sons, Ltd.

Music as noise: Sound transmission and unbiased annoyance

Music is often perceived as noise pollution, especially when it invades one’s solitude or one’s own music making. This is generally a major issue in multiunit residential buildings and in music facilities for rehearsal, broadcast, and recording. However, current noise control methods of design and classification do not address the ongoing trend in popular music toward strong bass content. Analysis of broadcast music signals using unbiased annoyance [E. Zwicker, ‘‘On the dependence of unbiased annoyance on loudness,’’ Proc. Internoise 89, pp. 809–814] indicates that (i) contemporary music can be adequately modelled as pink noise from 50 to 4000 Hz, (ii) after passing through a partition the 63‐Hz octave band dominates loudness and unbiased annoyance, (iii) existing single‐number ratings (such as STC) cannot identify structures with critical low‐frequency resonances, thus potentially overestimating performance against this type of noise. Ramifications for noise control practice and effective single‐number ratings are explored.

State-of-the-Art of Precast Concrete Sandwich Panels

Maher K. Tadros Cheryl W. Prewett Professor of Civil Engineering and Director Center for Infrastructure Research University of Nebraska Omaha, Nebraska Precast Concrete Sandwich Panels (PCSP), used as exterior walls in multi-unit residential, commercial, and warehouse buildings, are structurally and thermally efficient building elements, and they are in use worldwide; yet, there is very limited available information on the various design, production and construction philosophies. This paper presents the PCSP systems most widely used in North America and Europe as exterior walls for low rise commercial and warehouse buildings. The constituents of these panels are described, and some of the limited available research results are discussed. The theory of analysis for volume change effects is explained and numerical examples are given. A discussion of issues in need of further research is provided. Some widely used PCSP systems in North America and Europe are described in Appendix A, and the names of producers are included for further reference.