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The architectural engineer has a considerable influence on the sustainability of buildings. The reduction in environmental impacts of building materials, as measured by life-cycle assessment (LCA), has recently become a focus in construction sustainability initiatives. The LCA comparisons of material alternatives in building structures, like concrete and steel, have not captured the material efficiency that the comparisons of structural system alternatives can provide. This paper compares the LCAs of two long-span structural systems, a truss system and a cable system, for the same application. Lower environmental outcomes are shown for the cable system when comparing the two systems' LCAs. Results showed a 29% reduction in structural system mass, a 65.1% reduction in embodied energy, and a 67.2% reduction in carbon dioxide () emissions when comparing the cable to the truss system. [ABSTRACT FROM AUTHOR]

This study analyzes simulated secondary (site) energy consumption before and after applying a series of building envelope retrofits to inform a prioritized list of retrofit options tailored to one of four single-family dwelling styles in Toronto, Ontario, Canada. Four archetype homes were developed to represent Toronto's existing urban housing stock: (1) 2-story century home; (2) wartime bungalow; (3) 1970s Ontario Building Code 2-story home; and a (4) 2-story modern house. Base case geometry and inputs were developed from a variety of sources, including a Canadian national database and modeled using the HOT2000 software package. The prioritized retrofit strategy worked toward achieving a target secondary energy intensity of and included increasing insulation levels in the main walls, foundation walls, slab, and ceiling, replacing windows and doors, and air sealing to various degrees. Results showed the retrofit strategies affected each archetype differently, leading to the conclusion that certain retrofits would have a much greater impact on one typology compared with another. Archetype specific recommendations were made that showed a generic approach to retrofitting an urban housing stock might not be the optimal solution. [ABSTRACT FROM AUTHOR]

The green building trend has increased rapidly worldwide in recent decades as a means of addressing growing concerns over climate change and global warming and to reduce the impact of the building industry on the environment. A significant contribution in Australia has been the use of a series of rating tools by the Green Building Council of Australia (GBCA) for the certification of various types of buildings. This paper reviews the use of the Green Star system in Australian building construction and investigates the potential challenges involved in acquiring such certification for Australian buildings, by critically analyzing a database of the most recently certified GBCA projects. The results show that management-related credits and innovation-related credits are the easiest and most difficult, respectively, to obtain. Additionally, 6 Star green buildings achieve significantly higher points than do other certified buildings in the energy category. In contrast, 4 Star green buildings achieve more points in the material category than do 5 and 6 Star buildings. The study offers a useful reference for both property developers and project teams that can help them obtain a better understanding of the rating scheme and consequently aid in the effective preparation of certification documentation. [ABSTRACT FROM AUTHOR]

Generally, in seismic retrofit design, seismic performance of a RC building can be upgraded to meet or exceed code requirements by upgrading the structural strength, ductility, or a combination of both. Except for safety, financial and environmental benefits of seismic retrofit investments are not considered in seismic retrofit design. However, financial and environmental benefits are very important information for decision making in seismic retrofit investments. In this work, a novel method for estimating seismic damage to an RC building is constructed based of the hazard curve of response spectral acceleration. Additionally, earthquakes are assumed to follow a Poisson process when analyzing the probability of a specified damage state within a specified service period and modeling expected costs caused by seismic damage. In addition to costs, emissions caused by seismic retrofit and repairs are considered the environmental impact when assessing payback periods of seismic retrofit investments based on the economic and environmental aspects of low-rise RC buildings. In a case study, 16 practical seismic retrofit projects for RC school buildings in Taipei, Taiwan, were analyzed to determine their financial and environmental payback periods. This paper shows that return on the seismic retrofit investments was both environmentally and economically positive. [ABSTRACT FROM AUTHOR]

Studies have shown that poor indoor environmental quality (IEQ) has adverse effects on the occupants' health, comfort, and well-being. There is evidence suggesting that investing in better IEQ could be profitable through modest improvements in productivity. However, there are limited studies providing holistic environmentally responsible interior design (ERID) solutions. Knowledge professionals in the industry need to improve IEQ, indoor air quality, and thermal, acoustical, visual/light, spatial, and building integrity. This paper attempts to address this practical knowledge gap by providing a case study that examines the IEQ conditions of air-conditioned office space in Dubai before providing ERID solutions to address the problems observed. The study was conducted by distributing questionnaires (i.e., an administration survey known as a subjective measurement) to the office occupants to get their perception of their office IEQ conditions. An expert walk-through investigation was also conducted. The integration of the structural, envelope, mechanical, and interior systems, and their contribution toward ERID, was taken into consideration during the expert walk-through investigation. Objective measurements were conducted to obtain an unbiased understanding of the office IEQ conditions. The findings from the methods adopted indicate that the office IEQ was unhealthy and not environmentally responsible, thus justifying the need for providing ERID solutions. This study is significant because it addresses issues relevant to building occupants' health and comfort and building sustainability. [ABSTRACT FROM AUTHOR]

High-performance green buildings require close integration of building systems with a special focus on energy, daylighting, and material analysis during their design processes. Design process modeling and use of visualization tools can facilitate better communication and collaboration between team members; hence better integration in the design process. This paper presents a case study of the integrated design process of an Early Childhood Learning Center as performed by a team of university students and faculty. A process modeling approach of key decisions, required consultants, and virtual prototypes of the building was used during the design development stages of the case study. This case illustrates the use of process modeling and visualization tools to provide an accurate building information system for integrated teams. Through this experience, process modeling and visualization tools were found to be useful mechanisms to achieve high performance design goals and minimize design process waste. [ABSTRACT FROM AUTHOR]

The expansion and advancement of businesses, cities, municipalities, and populations in Canada are increasingly demanding the effective usage of land and resources in building development. Companies, organizations, and individuals are seeking to construct more environmentally responsible buildings to help minimize the negative effects that structures place on the natural environment, as well as on the people that have either direct or indirect contact with them. In an effort to set a benchmark for what constitutes a green building, the Canada Green Building Council provides a certification system called Leadership in Energy and Environmental Design (LEED), which is a point scheme that seeks to measure sustainability. Many stakeholders in the construction industry in Canada are increasingly employing this system to validate their achievement in sustainable development. This paper reviews the usage of the LEED system in Canadian building construction and the potential challenges and barriers associated with LEED implementation that specifically pertain to Canadian circumstances. Information from 42 new construction projects across Canada that achieved LEED certification were collected and analyzed. The points most often awarded, as well as those that are granted the least frequently, were tabulated. The percentages of points obtained were compared to American projects. Credit frequency indicators (CFIs), which were used to depict the achievement of credits by each project, can provide decision makers with information on credits awarded in the past and insight into credit implementation in future projects with similar goals. The energy and atmosphere and materials and resources categories proved to have the lowest CFIs, whereas the innovation and design process and water efficiency categories yielded the highest CFIs. The study also found that there were differences in the points obtained by LEED projects in Canada and the United States as some credits are influenced by climate, such as weather and temperature, as well as regional location. [ABSTRACT FROM AUTHOR]

In these times of global change, many facility emphases are competing for limited resources. Competing factors include, but are not limited to, sustainable design or green buildings; security, hardening or force protection; accessibility; historic preservation; aesthetics; and functionality. Yet, unlimited resources are seldom, if ever, available to fulfill all of these competing requirements in private or public construction. The Georgia Institute of Technology designed a decision matrix to allow owners and planners to balance these competing requirements on a project-by-project basis and to document the rationale. [ABSTRACT FROM AUTHOR]

Construction of commercial buildings consumes significant amounts of energy and produces lots of emissions and waste. Where should environmental improvement efforts be focused during design and construction? The Construction Environmental Decision-Support Tool allows designers and industry practitioners to quantify energy use, emissions, and waste generation rates due to the construction phase of commercial buildings. A case study of the Bren School at the University of California, Santa Barbara, and several relevant construction scenarios are analyzed. When considering the complete building over its entire life cycle, the construction phase comprised 2% of energy consumption, 1% of CO2 emissions, 7% of CO emissions, 8% of NOx emissions, 8% of PM10 emissions, and 1% of SO2 emissions. This is due to the dominance of the long-term use phase (50 years) compared to a relatively short construction phase (2 years). Scaling up to the national level, however, construction impacts of projects are significant. In each of the categories studied (temporary materials, equipment and materials transportation, equipment use, waste generation), there are actions that can be taken by designers and builders to improve construction phase environmental effects. In structural frame construction, particular areas of concern include material and equipment selection and temporary material use. Energy use and air emissions are primarily due to equipment use, which accounts for at least 50% of most types of emissions. The major contributors are concrete mixer trucks, concrete pumps, cranes, and air compressors. A single feasible decision, such as using a concrete mixer truck with a 335 hp engine instead of one with a 565 hp engine (but having the same capacity) would reduce total construction energy demand by 12%, and the emissions of CO, NO2, PM10, SO2, CO2, and HC by 3, 12, 8, 10, 12, and 10%, respectively. The use of significantly older equipment can have a formidable effect on construction phase emissions. In general, equipment larger that 175 hp made prior to 1996 tends to have significantly greater emissions of HC, CO, and NO2 than more recent models. The majority of waste generated during construction of the structural frame consists of concrete and wood. [ABSTRACT FROM AUTHOR]

Sustainable design should be applied in all phases of the life cycle of a building, including programming, design, building construction, building operation, and finally demolition. This paper compares and contrasts sustainable design programs based on the life cycle of a building in North America, Europe, and Asia. Tables comparing programs from these three regions are provided for each phase in the life cycle of a building. These tables can be used by building design professionals as a reference guide to sustainable design around the world. The tables also highlight specific requirements or concerns that are applicable in a particular region. The similarities between different programs and regions can be taken into consideration during the planning of sustainable design work, regardless of the region of construction. Finally, references to more detailed program documents are provided so that interested readers can determine specific requirements that apply in a region of interest. [ABSTRACT FROM AUTHOR]

This paper briefly describes the background to light earth buildings and details a series of moisture measurements undertaken upon the clay and straw (light earth) constructed walls of two U.K.-based buildings. The methodology of measurement that was based upon previous studies undertaken on walls made from straw bales is described. A novel “in-wall” wet heating system used in one of the two buildings allows the investigation of the effects of direct wall heating upon the distribution of moisture in the walls. The influence of exterior and interior temperature and humidity are described as are the variations in moisture migration introduced by the in-wall heating system. It was concluded that both buildings have exterior wall moisture content readings that indicate little risk of degradation due to interior wall moisture levels (although the Studio walls do exhibit higher and if suffered over long time periods, dangerous moisture readings for part of the measurement period). [ABSTRACT FROM AUTHOR]