I have conducted a comprehensive literature review that has been taken from a wide range of academic sources and the following sections will show the changes which has happened in the construction industry. From industry publications, respected journals, and government publications, this review explores the needs to achieve sustainable architecture in a modern built environment. Focusing specifically on the developments and techniques used in construction, the information collated therefore presents both the beneficial and challenging requirements of the sustainability process. The requirements for greener, more sustainable buildings and technologies require an in-depth understanding of the environmental and ecological interactions of a given structure. Through investigative, pre-design analysis, this research represents opportunities for the architect to overcome particular deficiencies in order to meet the demands of an increasingly demanding construction industry. From client base to government influences and changes in the way we think, this research also introduces those challenges which must be navigated in order to ensure that such architectural changes are both functional and representative of the overwhelming change in the climate of sustainability.
Introduction to Sustainability
"There is a fundamental misconception that sustainability and the environment are one and the same issue." Sandy Haliday ( Sustainable Construction) but over the years Architects and Designers have tried to emphasize that sustainable architecture is concerned with the buildings which are then adapted to come into line with the environmental issues bearing in mind the location , climate and the use to future generations. The main aim is to minimize the
energy consumption through the use of design techniques and adaption of the building to the
local climate, as sustainability has become a mainstream focal point for modern construction .We all have to recognize that there are many problems in the definition of sustainable construction.
Greener Homes for the future
In the UK the government has brought in a series of standards which have been introduced into the building industry "The code is the National Standard for the suitable design and construction of new homes. The code aims to reduce our carbon emissions and create homes that are sustainable." The law was introduced in England on 1st May 2008 that all new homes built will be rated on a scale. The government also has a target that by 2016 that all new homes built will be zero rated with the reduction of energy, water and waste and by 2019 all other non domestic buildings will fall into line.
For existing dwellings the government has introduced EPC which stands for (" Energy Performance Certificate." ) so that home owners can try and adjust their homes in line with the change in more environmentally free issues. .
In 1994 America introduced efforts to promote sustainability and introduced (LEED) Leadership in Energy and Environmental Design which concentrates on designs and buildings. Using this process there is a variety of guidance and government initatives which have been implemented which enables builders to use the resources so they are more efficient with a credit based system that rewards sustainable structural features ( Newsham et al .2009:897). This allows architects to concentrate on optimizing their building design in order to reach the required LEED expectations.
In spite of the standard review imposed by LEED audits, the question remains as to whether or not LEED is effective in enhancing the sustainability of the modern built environment. Analysis of the LEED program installed in the US construction sector by Newsham et al. (2009:903) returned mixed results regarding improved structural efficiency and energy demands. In particular, this research suggests that the majority of LEED-certified structures is using less energy in comparison to their equal conventional counterparts; however, between 28 and 35% of the certified LEED structures are the opposite and are not meeting their expectations and are actually using more energy than conventional structures (Newsham et al., 2009:903). In addition, their analysis of the programmes success rates offered evidence to suggest that the energy credits received do not necessarily contribute to the greening of a given structure in terms of energy consumption, as they are too general in nature, focusing on too broad of a segment of the construction industry (Newsham et al., 2009:903). Ultimately, architects must assume such responsibilities to integrate more sustainable techniques into their design processes.
In both new and lived in structures, the impact on the design when compared to more energy efficient dwellings the modifications must be weighed up by the architect prior to making any significant changes. Heiselberg et al. (2009:2035) offers evidence from a lifecycle analysis study in which design parameters are their first concern rather than the impact of the overall efficiency of a structure; and lighting control and ventilation systems are secondary and their design has to have substantial benefits on the overall energy demands during operation. In the conquest to overcome material shortages and to continue to advance the state of the construction industry towards more modern design and build techniques, a variety of revolutionary processes have been recently developed. Shi and Han (2009:6), for example: They propose structural fine-tuning and combinative systems modeling as a means of improving the height and stability in high-rise commercial structures. In particular, their research focuses on the adaptation and incorporation, reducing the force of some components by transferring it to alternative positions in the building frame (Shi and Han, 2009:11). Ultimately, such techniques will utilize a mix of both conventional and green materials to advance large scale structures beyond their current limits and expectations
Green Materials, Components, and Design Integration
As architects consider the inclusive technologies and materials for a given structure, the integration of green components should radically improve the overall operational efficiency of a given building. Recent analysis of building plans by Pan et al. (2008:1151) suggests that the integration of sustainable techniques including both production and regulatory mechanics can provide a 27% annual cost savings in energy, optimizing the power flow throughout the structural environment. From lighting to passive cooling, such techniques strategically improve upon once ailing structural systems, advancing building performance through the integration of new technology and more efficient green materials. Lam et al. (2010:657) "remind us that in the sustainability strategy, material optimization and installation technique should be considered the most important products in enhancing the greenness of a given structure." Their research highlights accessibility, process adoption, and material selection as primary influences in structural sustainability.
One of the primary means of 'greening' a modern structure is the inclusion of renewable or alternative energy sources that reduce the overall burden on the national energy infrastructure. Case Study 1:1 Solar Hemicyle Middletown Wisconsin. In 1945 "Architect Frank Lloyd Wright designed a house which was an early example of passive solar design Earth was placed against the north wall for insulation and the southern wall has 2 storey's of glass to maximize solar gain in the winter."
In particular, Zhai et al. (2008:1904) mentions the benefits of various solar collection mechanisms which provide for the interior wellbeing of a given structure while also offering configurations that can heat the entire building's water supply. In fact, the researchers recognize that in both residential and office applications, solar collectors can be integrated with minimal structural or operational interference, and improving the overall look of the structure and meeting its energy demands (Zhai et al., 2008:1909). " Given the broad façade of the built landscape, the benefits of integrating energy collection technology are significant, ultimately reducing overall demands placed on the national energy infrastructure."
From a practical and cost-effective perspective build programme, many researchers have adopted the belief that the use off-site construction materials are much more efficient than piece by piece assembly on site of the various structural components. Buswell et al. (2007:229) "recognize such offsite methods as the future of construction, highlighting flexibility in materials, control during installation, as primary benefits of these techniques." While off-site manufacture may provide benefits in efficiency and structural benefits, the cost implication of these materials is considerably higher than their conventional counterparts. Wang et al. (2010:7) warns that the cost feasibility analysis of particular structures may reduce the validity of using green components compared to more conventional technologies. While, during the collection of a survey from a variety of industry participants, the feedback was both positive and supportive, lifecycle cost analysis weighed heavily on the participant decision making, resulting in both support and rejection of greener installations (Wang et al. 2010:7). Evaluating the positioning of both prefabricated and conventional materials in relation to cost, efficiency, and structural demands provides the architect with a weighted position that can determine the most effective tactic used in the final design.
Installation Strategies and Technical Specifications
"Over 70 million tonnes of waste is produced in the construction Industry each year." "(Keys Baldwin and Austin., Dept of civil and building Engineering Loughborough University) One of the primary means of enhancing the sustainability of a given structure is the reduction of waste throughout the building process, ideally initiated in the design phases by the architect he strives to have an active waste management strategy. Researchers such as Kourmpanis et al. (2008:270) propose an on-site method such as selective demolition as a means of improving material recovery for recycling or reuse, the responsibility for waste reduction in the building itself falls to the architect. Osmani et al. (2008:1157) produce substantial evidence from a variety of industry architects in order to evaluate the feasibility of design phase waste reduction. In particular, their research highlights opportunities and challenges, all arising from the architectural perception of waste, unknown causes of waste, client's expectations, and poor representation of builders responsibilities (Osmani et al. 2008:1157). Such research highlights deficient standards in architectural processes, namely from a point of poor translation and strategic management. In order to overcome such challenges, greater awareness of the end generation of waste must be developed, focusing on recycling schemes that can reduce the amount of waste and improve project value from the design phase of a given project.
One of the overwhelming challenges architects are up against is the identification and installation of efficient system components and the difference they have between change and impact. Juan et al. (2010:293) provides research to support the use of a comprehensive genetic algorithm (GA) analysis system which integrates a hybrid search algorithm (A). This particular analytical tool enables architects and designers to evaluate variable elements in a given system, based on the probability of acquiring and installing optimal solutions for both new and lived in structures (Juan at al., 2010:294). Based on a ranking system that establishes renovation , budget, savings, and environmental considerations as direct influences on feasibility, such research allow participants to realistically evaluate options according to a degree of impact. Ranking particular choices, on an improvement scale, the GA analytical tool allows for important decisions to be weighed and made according to the long term site and client objectives and requirements. A similar use of the GA has been recognized in building design allowing architects to layout their floor plans and building orientation designs according to climate and occupancy . Wang et al. (2006:376) suggest that through multi-objective GA, analysis of design solutions can be realised, offering insight into length, shape, and angle of various structural points in order to improve function at both the occupanancy and energy levels.
Architectural Challenges and Strategies
In developing a strategic position within the construction industry, architects have held onto the responsibility for the development of the future-structure, a blend of both past and future concepts that links sustainability with functionality. Research conducted by Melchert (2007:896) suggests that the initial departure from conventional construction tactics towards more sustainable structure resulted in some confusion, as architects resisted a significant departure from more traditional structural characteristics. In fact, his research highlights an ecological emphasis during the design phase which linked structural characteristics to the local environment and the long term occupancy of a given building (Melchert, 2007:896). Focusing on such fundamental characteristics would eventually contribute to more radical design choices; however, validation of new designs and structural revolution would require an increasingly open industry perspective. From ecological interactions to structural feasibility, architects must valuate particular decisions as they relate to building configuration and site optimization, meeting the demands of the client while improving structural sustainability. All in all a massive change for everyone involved in the building industry.
When considering the structural configuration and features of new buildings, architects must evaluate the local surroundings from a critical position. Omer (2008:2289) cites evidence of ventilation noise in dense urban areas, resulting in increased stress on energy systems, including heightened demands for structural cooling in particular climates. Recognizing that both the height and size of structures have variable impacts on such deficient systems, Omer (2008:2289) proposes that decisions are made on an industry level to impose variable restrictions on structural characteristics. In particular, such initiatives would include variable heights and spacing to allow for improved passage of air across the buildings and city landscape. In line with such structural orientation arguments.
Ong (2003:210) proposes that a green plot ratio must be used to determine how much greenery we are loosing due to a new development. So rather than architects looking for new modern technologies to help combat climate change they should be concentrating on new ideas and innovations regarding blending in plants, roof gardens and shrubs into the design process, placing ecological considerations at the forefront of design and planning initiatives (Ong, 2003:210).
Design Optimization and Component Management
Observation and survey results of occupancy living and comfort levels under both green and conventional construction techniques has returned mixed results. In particular, evidence presented by Paul and Taylor (2008:1866) suggests no significant difference between either property characteristics, suggesting that the improved environmental designs in the green structure had limited positive or negative impact for the occupants. Yet the authors mention that such research is deficient in parts, citing evidence of a breakdown in some of the system components in the evaluated structures that could have substantively limited the overall comfort performance. Paul and Taylor (2008:1866) do, however, produce results that link environmental satisfaction to comfort perceptions in a given building. Therefore, should the occupants feel the adverse effects of non-functional or malfunctioning systems, their overall satisfaction rating for a particular structure will be negative? These findings place value on systematic evaluation of occupant buildings yet caution against typifying such reported discomfort until further system inspection can be completed and more surveys undertaken..
There are several variables at work in the decision making role which an architect must assume in order to optimize structural sustainability. Similar to Paul and Taylor (2008), more recent research by Lee and Guerin (2010:1111) links satisfaction of building occupants to thermal and lighting quality. Their findings, taken from a variety of LEED certified structures, validate operational programming considerations that must be taken into account by architects seeking to optimize structural characteristics. From space and proximity concerns to structural positioning, lighting and ventilation concerns, the role of the architect has been directly impacted by sustainable practices and an increased demand for more greener, sustainable building designs (Lee and Guerin, 2010:1111). Architectural calculations now integrate into causal design modeling, evaluating the positioning of various building features as a means of facilitating environmental flow and enhancing the overall function of the demanded structure.
This research has introduced a variety of new responsibilities and architectural strategies that continue to evolve the design phase and construction management of sustainable buildings. From occupant comfort and functionality (Paul and Taylor, 2008; Lee and Guerin, 2010) to efficiency modeling and waste reduction (Osmani et al., 2008; Juan et al., 2010), this investigation has presented a perspective of change that continues to impact the functions and methods in architectural initiatives. New technologies continue to redefine the built environment. Zhai et al. (2008) introduced the solar collector as a primary means of utilizing the building façade on a more functional level. Pan et al. (2008) emphasize the benefits of passive cooling systems as a means of reducing energy consumption during structural ventilation. The future of architecture is directly linked to structural aesthetics, functionality, and technological optimization. This research has presented a vision of alternative strategies and methods from a pragmatic perspective, emphasizing application of such consistent techniques within variable building designs. While researchers such as Shi and Han (2009) propose that optimizing design variables will enable structural capabilities to be extended, from a more realistic perspective, the benefits of sustainability are visible at the core of any given structure. Utilising energy performance and reducing the building's reliance on the national energy infrastructure will radically improve the state of the built environment over the coming decades.