L. Bragança

Early Stage Design Decisions: The Way to Achieve Sustainable Buildings at Lower Costs

The construction industry attempts to produce buildings with as lower environmental impact as possible. However, construction activities still greatly affect environment; therefore, it is necessary to consider a sustainable project approach based on its performance. Sustainability is an important issue to consider in design, not only due to environmental concerns but also due to economic and social matters, promoting architectural quality and economic advantages. This paper aims to identify the phases through which a design project should be developed, emphasising the importance and ability of earlier stages to influence sustainability, performance, and life cycle cost. Then, a selection of sustainability key indicators, able to be used at the design conceptual phase and able to start predicting environmental sustainability performance of buildings is presented. The output of this paper aimed to enable designers to compare and evaluate the consequences of different design solutions, based on preliminary data, and facilitate the collaboration between stakeholders and clients and eventually yield a sustainable and high performance building throughout its life cycle.

The evolution of the sustainability assessment tool SBToolPT: from buildings to the built environment

This paper analyses the current trends in sustainability assessment. After about 15 years from the launch of sustainability assessment tools, focused on buildings evaluation, the paradigm of sustainability assessment tools is changing from the building scale to the built environment scale. Currently European cities and cities around the world are concerned with sustainable development, as well as its evolution. Cities seek a way to adapt to contemporary changes, in order to meet the required needs and ensure populations well-being. Considering this, the new generations of sustainability assessment tools are being developed to be used to guide and help cities and urban areas to become more sustainable. Following the trend of the most important sustainability assessment tools, the sustainability assessment tool SBToolPT is also developing its version for assessing the sustainability of the built environment, namely, the urban planning projects and the urban regeneration projects, to be developed in Portugal, the SBToolPT-UP. The application of the methodology to three case studies will demonstrate its feasibility; at the same time this will identify the best practices which will serve as reference for new projects, thereby assisting the development of the tool.

Thermal mortars with incorporation of PCM microcapsules

The main purpose of this work is the production of a mortar with incorporation of Phase Change Materials (PCM) microcapsules, which must have a compromise between workability, mechanical strength and aesthetic appearance. The mortars studied in this work are mixed mortars of lime and gypsum. The proportion of PCM is 0 %, 10 %, 20 % and 30 %. In order to minimize some problems associated with shrinkage and consequent cracking of the mortars, the incorporation of nylon fibers, superplasticizer and gypsum was tested. A study of mechanical characteristics and some sensitivity tests for qualify the shrinkage of the fifteen compositions was realized. In this way, one composition for the application in tests cells was selected, with the aim of studying the thermal behaviour of these mortars. The test performed on test cells includes the study of a standard mortar without addition of PCM and a mortar with incorporation of an ideal percentage of PCM. Based on the obtained results it was possible to conclude that the incorporation of PCM microcapsules in the studied mortars causes an increase in mechanical strengths and shrinkage. The tests performed on test cells allowed to verify a time lag in maximum and minimum temperatures, as well as a slight attenuation in the temperature variation. It can be concluded that the use of PCM microcapsules in mixed mortars of lime and gypsum can be assumed as a viable solution for applications in the construction industry once these present a compromise between their resistance, aesthetic appearance and thermal behaviour.

Properties of Gypsum-PCM Based Mortars for Interior Plastering of Construction Systems

Incorporating phase change materials (PCM) in plasters is an effective solution both for more efficient use of energy and its consumption reduction, because it allows the use of free energy in the environment, by latent heat storage. As PCM has not binder properties, it is expected to decrease mechanical properties of the final mortar. Also the density of the mortar decreases due to PCM lighter specific weight. In order to be used as a final coat for wall plastering, it must verify the requirements of the respective European Standard. This paper presents the results of the composition development and mechanical properties (flexural, compressive and adhesive strengths) testing and validation of three different gypsum mortars, in order to select the appropriate one for thermal testing in test cells. The results show that the effective decrease in the studied characteristics of the mortar does not inhibit the use for plastering, as requirements are achieved by the three studied compositions.

A critical analysis of building sustainability assessment methods for healthcare buildings

The healthcare building project contains different aspects from the most common projects. Designing a healthcare environment is based on a number of criteria related to the satisfaction and well-being of the professional working teams, patients and administrators. Mostly due to various design requirements, these buildings are rarely designed and operated in a sustainable way. Therefore, the sustainable development is a concept whose importance has grown significantly in the last decade in this sector. The worldwide economic crisis reinforces the growing environmental concerns as well as raising awareness among people to a necessary and inevitable shift in the values of their society. To support sustainable building design, several building sustainability assessment (BSA) methods are being developed worldwide. Since healthcare buildings are rather complex systems than other buildings, so specific methods were developed for them. These methods are aimed to support decision-making towards the introduction of the best sustainability practices during the design and operation phases of a healthcare environment. However, the comparison between the results of different methods is difficult, if not impossible, since they address different environmental, societal and economic criteria, and they emphasize different phases of the life cycle. Therefore, the aim of this study was to clarify the differences between the main BSA methods for healthcare buildings by analysing and categorizing them. Furthermore, the benefits of these methods in promoting a more sustainable environment will be analysed, and the current situation of them within the context of standardization of the concept sustainable construction will be discussed.

Assessment of land use efficiency using BSA tools : development of a new index

AbstractIn this article, the sustainability assessment of land use efficiency of buildings is subject to a critical study. Several building sustainability assessment (BSA) tools were analyzed, finding that the impacts of this criterion are not correctly assessed in current methodologies and some even ignore its importance. Some existing assessment methods and corresponding indexes were used in four virtual buildings to evaluate the effectiveness of each calculation method. It was concluded that the existing methods do not provide correct assessments and can promote unsustainable practices. It was also proved that it is necessary to include the implantation index, spatial efficiency, and occupational efficiency for correct assessments complementary to the use of the gross floor area index or development density. Due to difficulties in the weighting of the four complementary indexes, a single index was developed to perform the calculations using five main variables. The new index was tested in seven virtual...

Thermal performance of lightweight steel framed wall: The importance of flanking thermal losses

The thermal performance of a modular lightweight steel framed wall was measured and calculated with three-dimensional finite element method model. The focus of this article is on the effect of flanking thermal losses. The calculated heat flux values varied from −22% (external surface) to +50% (internal surface) when flanking loss was set to 0 as a reference case, thermal transmittance equal to 0.30 W/(m2·K). Other critical parameters were the existence of fixing ‘L’-shaped steel elements and the perimeter thermal insulation (10 cm XPS).

Sustainability assessment of dwellings - a comparison of methodologies

ABSTRACT Building sustainability assessment tools (BSATs) aim to promote and rank the sustainability of building stock. This paper makes a deep comparative analysis on how dwellings are evaluated by five BSAT and one performance-based design tool. The comparison is based on: (i) the purpose of assessment; (ii) sustainability dimensions considered; (iii) indicators addressed; (iv) life cycle phases considered by the indicators; (v) type of indicators; (vi) measurements; (vii) aggregation processes; and (vii) life cycle phases during which the assessment was carried out. The evaluation showed that the scope of BSAT varies significantly as well as the life cycle phases addressed in the assessment. Financial issues are often excluded from the assessment. None of the schemes is totally quantitative or qualitative in their measurement system; all have different types of indicators and different ways to assess them. This research provides researchers and stakeholders with important inside knowledge on the tools that allow the development and construction of more sustainable buildings.

Portuguese vernacular architecture: the contribution of vernacular materials and design approaches for sustainable construction

Vernacular architecture is characterized by a type of formal expression, which has been developed in response to a number of factors – geographic, climatic and economic – characterizing the local area or region. Despite the fact that Portugal is a small country, there are many different architectural approaches and a range of techniques have been employed in different regions to mitigate the effects of climate. These vernacular approaches have the potential for further development and could be adapted in response to contemporary needs. In this paper, a range of different passive solar techniques used in Portuguese vernacular architecture to provide comfort is presented. The specific focus is on the effectiveness of passive cooling strategies (namely, high thermal inertia, use of light colours and courtyards), and the findings of a case study in which the thermal performance during the summer of a vernacular residential building located in the south of Portugal are presented.

Adaptation of SBToolPT to office buildings

The few available sustainability assessment tools applicable in Portugal are oriented for residential buildings. Nevertheless, the impacts of office buildings have been rising mainly due to an increase in the energy consumption for cooling and heating. This way, due to the growing environmental impact of office buildings, the development of Building Sustainability Assessment (BSA) tools to assess the sustainability of this type of buildings is necessary and important to guide and to boost the construction sector towards sustainable development. The main objective of this work was to develop a sustainability assessment tool aimed at office buildings based in SBToolPT-H. The work includes the definition of the tools framework and assessment method, as well as the Portuguese benchmarks and weighting system used in the aggregation. In order to promote the practical use of this tool, an evaluation guide was also developed in which there is detailed information about calculation methods and aggregation models....