Architectural Membranes for improving the functional performance of buildings

A well designed envelope separates the interior from the exterior so that the internal conditions are maintained with the minimum energy consumption. Due to its reduced weight, architectural membrane solutions may present some functional problems, namely acoustic and hygrothermal, when compared to conventional, heavier solutions. However, they also have potential and ecological advantages that can be exploited to enable the functional optimization of existing buildings in a sustainable way, due to the minimal use of material and the fact that they are dry assembling, easily reusable and recyclable solutions. This paper presents some emergent technologies for applying architectural membranes in building envelope, revealing ways to overcome the limitations for that they are recognized. Current trends include: hybrid membranes and coatings resulting from nanotechnology solutions; membranes with embedded smart technologies (batteries, LEDs, sensors), membranes incorporating Phase Change Materials and membranes for the purification and regulation of indoor air quality. Technological innovation in this field has advanced at an extraordinary pace in the last decades and has generated solutions that in some cases present functional performance equivalent to conventional solutions, but with less environmental impact.Erasmus+. SFRH/BD/104891/201

Lightweight dividing walls : adaptation to temperate climates

This paper intends to prove that it is possible to use lightweight membranes on interior partition walls and on external façades, even in housing buildings at temperate climate regions, if their properties are well explored. The few material used, even less than conventional lightweight solutions - the most common is plasterboard with light steel frame structure - allow a lower specific embodied energy and other more favourable environmental impact indicators. Compared to conventional heavyweight solutions, such as hollow brick walls, lightweight membranes allow easier deconstruction/reuse. In the outer skin, architectural membranes can be used as passive or active systems, for heating (promoting greenhouse effect) and cooling (shading or even evaporative cooling). Lightweight materials are more viable to be used on invariably hot or cold climates, than on temperate climates, as in this context they present problems related with its low thermal storage capacity. However, the research of new architectural membrane materials, with passive and active behavior for thermal regulation, allows extending its possibilities to interior dividing partitions in order to fulfill contemporary demands of comfort. Active and/or passive systems can be used to regulate thermal gains – for example by radiant panels and/or evaporative cooling, but also to achieve thermal inertia. In pavements, thermal storage lightweight elements, using natural Phase Change Materials, were already studied and reported on previous studies from the first author. Examples of how these systems can also be applied to lightweight membrane dividing walls are presented in this paper, and some experimental research is now under course on test cell facilities existing in University of Minho, Guimarães.Fundação para a Ciência e a Tecnologia (FCT

Characterization of porous acoustic materials applied to lightweight partition walls

The increased need to save material and energetic resources, allied with a growing concern on the environmental issues and incertitude on the evolution of the economy, has impelled minimalist-approaches to Architecture and Engineering, reducing to the minimum necessary expression the building elements. The development of new lightweight materials, most of them composites with fibrous reinforcement systems, has interest for building materials and textile industries. However, these materials still do not have a significant implementation in the building industry or, at least, this implementation is not being made exploring all their potentialities. Non load bearing interior partition walls are thin elements built to divide the indoor space into rooms or other compartments. Porous materials applied in interior partition walls have a significant importance in these building elements because sound insulation is an important requirement. Walls must provide an airborne sound barrier between rooms in a same dwelling and especially between different dwellings, this last issue as a compulsory requirement to fulfil in Portuguese regulations. In the present study it will be considered a lightweight interior partition wall composed by insulation material and layered within two membranes. The process of selecting materials for that interior partition wall is a challenging task. This paper intends to compare results of functional (acoustic and thermal) performance of materials such as expandable polystyrene (EPS), polyurethane foam (PU), Ethylene-vinyl acetate (EVA), 3D warp knitted polyester fabrics (3DWK), Cork (CK), Expanded Cork (CKE), Rockwool (RW), coconut fibber (CCF), silicone (SI), waste fiber (WF), to discuss about their potentialities as insulation or membrane materials applied in interior dividing walls technologies. It also presents a morphological characterization of materials, through microscopic analysis, in order to define the relationship between the morphology and acoustic performance. The results of tests are compared with reference values of rock wool as insulation material - conventionally used in lightweight dividing walls made of plasterboard leaves and light gauge steel framing structure. One of the results of this paper is that a lightweight and thin interior partition wall filled with insulation material present acoustic advantages when compared with a heavyweight interior partition wall with more thickness. The concept of membrane goes back to the Latin word “membrana”, meaning parchment or skin. In previous studies it could be verified that low density makes membrane structures poor thermal and acoustic insulators. However, it is available in the market heavily coated or microperforated membranes that have dampening effect A low density generally also implies a high porosity or a high volume of voids, which leads to a decrease in the thermal conductivity. In previous studies from the same authors, it was concluded that the presence of air gap between insulation materials in a lightweight interior partition can increase the acoustic insulation between 2 to 5 dB, the inclusion of porous materials in the air gap can contribute between 1 to 4 dB in thicknesses till 10cm. The compromise between thermal and acoustic performance should also be attended. However thermal performance is only a requirement for interior partition walls between useful and non useful areas in housing buildings. In this study it will be presented results for different densities of insulation material. In the process of airborne sound transmission between two spaces, should be distinguished: a) direct transmission, that occurs directly through the separation element; or b) marginal transmission - that occurs through other building elements interlocked to the element of separation in study. The direct transmission can occur through joints, cracks or discontinuance of the construction element or through the construction element vibration. The heat transfer coefficient calculation tests were conducted according UNE EN 6946. The sound insulation estimation between locals was conducted according to EN 12354-1. Procedures for measuring the reverberation of a room, the absorption of the covering layers, as well as the sound absorption coefficients of a specimen of sound absorptive material were made according to ASTM C – 423

Life-cycle assessment of lightweight textile membrane partition walls

This paper analyze the environmental, functional and economical performances of some conceptual lightweights textiles membranes partitions walls and to compare one of them with two technologies present in Portuguese market: i) the heavyweight conventional hollow brick partition wall; and ii) the lightweight reference plasterboard partition wall. Advantages of use textile/ fibrous/ membrane based materials in partition walls are focused and they may contribute for the development of new partition wall technologies. The comparative evaluation of these solutions is based on a standard Life-cycle Assessment method

Evaluating the efficiency of membrane's refurbishment solutions to perform vertical extensions in old buildings using a multicriteria decision-support model

The initial premise of this research is that the relative efficiency of refurbishment solutions with architectural membranes needs to be measured in order to allow its comparison with conventional solutions, helping decision makers to select the most efficient solutions. The evaluation of this efficiency depends on economic features, but also on functional, technological and environmental ones. This study presents a model to solve this problem, using decision trees, multicriteria decision-making methods (SAW and AHP) and a sensitivity analysis. The selection of the criteria and the assignment of the corresponding weights was attained through an expert group survey for a baseline scenario, aiming maximizing functional performance (such as energy savings) and minimizing employed resources (materials, costs, etc.). The most efficient refurbishment solution among the set of alternatives was reached using the developed model. The methodology was applied to a case study - an old building from the nineteenth century, located in Portugal, which was refurbished with a vertical extension. The result reveals that the proposed model is successful and illustrates the potential of this evaluation methodology to compare and quantify the efficiency of a series of different lightweight constructive solutions. It also underlines the advantages of using lightweight building technologies, especially with architectural membrane materials, in building refurbishments.This research was made possible by the support of the: Portuguese Foundation for Science and Technology (FCT), Portuguese Ministry of Education and Science (MCE) and European Social Fund (ESF) with the reference grant SFRH/BD/104891/2014; the Project UID/AUR/04509/2013 by FCTMEC by national funding and FEDER co-financing under the new PT2020 partnership agreement - Lab2PT, School of Architecture/University of Minho, Portugal; and Project POCI-01-0145-FEDER-007457 - CONSTRUCT - Institute of R&D In Structures and Construction of Faculty of Engineering/University of Porto, Portugal, funded by FEDER funds through COMPETE2020

Interior partition walls in mediterranean climates: lightweight versus heavyweight

The aim of this paper is to analyse the environmental and functional performance of interior partition wall technologies existing in Mediterranean climates, specifically on Portuguese territory. The evolution of interior partition walls, namely by the evolution of its weight, is presented and discussed. "Light-tech" bets on the introduction of more efficient systems by the weight reduction of constructive elements. This allows saving material and energetic resources, what constitutes a relevant response to the growing concerns over environmental issues and incertitude on economic development. But if lightweight solutions can be potentially interesting from the point of view of the environmental impacts associated with the production of materials, on the other hand it can be problematic from the point of view of the thermal comfort energetic demands. In a Mediterranean climate, the insufficient thermal inertia and acoustic insulation, due to the reduced mass of its constructive elements can constitute a severe problem. But thermal mass can be assured by slabs, exterior walls and in dwellings’ dividing walls. The functional problems associated with lightweight solutions are not as relevant in internal partitions. Apart from this, lightweight sandwich configurations can be used to increase thermal and acoustic insulation if the air gap between external finishing layers is filled by absorbent materials, such as rockwool. This paper focus on the advantages of the lightweight existing partition walls and it is expected that may contribute for the development of new partition wall technologies. The traditional lightweight solutions are compared with the conventional heavyweight solutions. The analysis shows that interior lightweight partition walls present lower environmental impacts than the heavyweight solutions.Fundação para a Ciência e Tecnologia (FCT) and COMPETE (Programa Operacional de Factores de Competitividade

Textile membrane design : case-study of a membrane house prototype in Portugal

The increasing speed in which technology is developing, as well as the social and economical changes are quickly turning buildings constructive systems and building design methodologies obsolete. The research on faster, cheaper and environmentally more respectfull building technologies are growing concerns in buildings design. These are some of the advantages of textile membranes. In a few millimeters membrane we have a self-supporting material, a sunlight filter capable of absorbing or reflecting the ultraviolet or infrared light and an isolating material for thermic or acoustic purposes. But there is some problems regarding such structures: the complexity of the calculations needed in such a minimalist engineering, regarding its structural design, the visualization of its forms - sometimes complex geometries, and the optimization of its functional performance - limited but also potentiated by its lightness and ephemerality. Computer-aided design has allowed designers of textile membrane structures to calculate its loads and determine their effect on projects quickly and more precisely, exploring various alternatives and options, turning the process not only cheaper, but also exploring new possibilities on the use of more efficient structures. There are also a significant number of softwares available that allow the functional performance evaluation of buildings, and that can also be used to evaluate textile membrane solutions with advantages related with easy and quick prediction of the building thermal performance during its service life. The apparently simple final result is normally the product of a very complex multi-criteria optimization process, from the membranes selection, the building design and calculation and the constructive systems adopted.The authors wish to thank FCT (Fundação para a Ciência e Tecnologia – Portugal) and COMPETE (Programa Operacional de Fatores de Competitividade - Portugal) for supporting the AdjustMEMBRANE Project with the reference PTDC/AUR-AQI/102321/2008

Evaluating the potential of using architectural membranes as an efficient alternative in the functional refurbishment of buildings

Tese de Doutoramento em Arquitetura (Área de especialização em Construção e Tecnologia)A atual e crescente importância atribuída ao impacto ambiental leva os projetistas a combinar o uso de materiais energeticamente eficientes com soluções técnicas que maximizem a poupança de recursos. Utilizadas essencialmente em estruturas exteriores de cobertura e proteções solares, as membranas arquitetónicas estão no entanto vocacionados para participar noutras aplicações construtivas. Neste sentido, o principal objetivo desta tese consistiu em avaliar a eficiência de tecnologias construtivas com membranas arquitetónicas, comparando-as relativamente às soluções convencionalmente utilizadas em intervenções de reabilitação funcional de edifícios. Para tal: (1) realizou-se uma análise do estado do conhecimento sobre reabilitação com membranas, com base num inventário de setenta projetos; (2) conceberam-se e avaliaram-se, através de ensaios numéricos e experimentais, soluções de reabilitação em membrana com potencial para melhorar o desempenho funcional de edifícios existentes e (3) aplicou-se um modelo multicritério que combina técnicas de apoio à tomada de decisão (AHP e SAW) e uma análise de sensibilidade, para determinar a eficiência relativa das soluções em membrana segundo critérios funcionais, técnico-construtivos, económicos, ambientais, de segurança, socioculturais e percetivos. A eficiência relativa das soluções em membrana foi avaliada através de três testes/casos de estudo em contextos de reabilitação específicos, numa relação de proximidade com a peculiaridade dos edifícios existentes, com o intuito de validar a utilização de soluções em membrana enquanto alternativas às convencionalmente utilizadas. Cada estudo representou uma abordagem arquitetónica comum em intervenções de reabilitação funcional - integração, sobreposição e reposição - preenchendo lacunas de investigação associadas ao uso de tecnologias de reabilitação com membranas arquitetónicas. A avaliação da eficiência depende de muitos critérios com escalas e interpretações nem sempre convergentes. Deste modo, concebeu-se, testou-se e validou-se um modelo de avaliação multicritério, acompanhado de uma analise de sensibilidade para auxiliar o processo de tomada de decisão a vários níveis, de modo a promover uma visão holística e estruturada do problema que permitisse encontrar a solução de reabilitação mais eficiente para um conjunto de critérios distintos. A aplicação deste método a casos de estudos concretos salientou o interesse das soluções propostas e confirmou a hipótese de que as soluções de reabilitação em membrana constituem uma alternativa eficiente às soluções convencionais. Com os diferentes exercícios, mostrou-se que é possível, no âmbito de uma reabilitação funcional, melhorar diferentes aspetos do edifício em simultâneo. Em particular, não é contraditório visar, simultaneamente, uma abordagem estética coerente, com uma redução do consumo de energia e uma melhoria do conforto, com consequentes vantagens económicas e ambientais. Como resultado, obtiveram-se respostas às seguintes questões: (Q1) Qual a eficiência relativa das soluções de reabilitação com membranas? (Q2) Quais os aspetos avaliados que mais beneficiam/ penalizam a eficiência das soluções em membrana? Quando é que as soluções com membranas arquitetónicas constituem uma alternativa eficiente às convencionais para a reabilitação de edifícios? Com esta tese demonstrou-se que as soluções de reabilitação com membranas arquitetónicas constituem alternativas eficientes às soluções convencionais de referência, em cenários de reabilitação funcional, sobretudo quando o peso e a reversibilidade/ repetibilidade constituem importantes fatores de decisão. Em suma, as soluções de reabilitação com membranas permitem que os edifícios se adaptem e atualizem segundo aspetos contemporâneos de sustentabilidade, apresentando-se como alternativas eficientes às soluções convencionais, com contributos para uma construção sustentável e inovadora. Contudo, apesar da crescente evolução dos materiais em membrana no passado recente, ainda existe um longo caminho a percorrer para que possam ser aceites e consideradas sustentáveis, também do ponto de vista social e cultural, sobretudo quando envolvem construções destinadas a uso residencial. Por fim, com base nas conclusões retiradas desta tese, sugerem-se algumas pistas para desenvolvimentos futuros.The current and growing importance attributed to environmental impact leads designers to combine the use of energy-efficient materials with technical solutions that maximize resources savings. Used mainly in roofing and exterior solar protection structures, the architectural membranes are however intended to participate in other constructive applications. In this sense, the main objective of this thesis is to evaluate the efficiency of constructive technologies with architectural membranes and comparing them to the conventional solutions, with focus on interventions for building’s functional refurbishment. For this: (1) it was made the analysis of the state of knowledge about refurbishment with membranes based on a project’s inventory of 70 cases; (2) it were designed and evaluated, through numerical and some experimental tests, membrane refurbishment solutions with potential to improve functional performance of existing buildings and (3) it was designed and applied a multi-criteria model, which combines decision support techniques (AHP and SAW) and a sensitivity analysis, to determine the relative efficiency of membrane solutions according to functional, technical-constructive, economic, environmental, safety, sociocultural and perceptual criteria. The relative efficiency of membrane solutions was evaluated through three tests/case studies in specific refurbishment contexts, in a close relationship to the peculiarity of existing buildings, in order to validate the use of membrane refurbishment solutions as alternatives to the conventional ones. Each study represented a common architectural approach to functional refurbishment interventions - integration, juxtaposition and replacement - filling research gaps associated with the use of refurbishment technologies with architectural membrane materials. The efficiency evaluation depends on many criteria with scales and interpretations not always converging. Thus, a multicriteria evaluation model was conceived, tested and validated, to aid the multi-level decision-making process in order to promote a holistic and structured view of the problem, making it possible to find the most efficient refurbishment solution for a set of distinct criteria. The application of this method to real case studies underlined the interest of the proposed solutions and confirmed the hypothesis that membrane refurbishment solutions constitute an efficient alternative to conventional ones. Through the different exercises/ case studies it was shown that it is possible, within a functional refurbishment action, improving different building aspects at once. In particular, it is not contradictory to target both a consistent aesthetic approach with an energy-consumption reduction and comfort improvement, with consequent economic and environmental benefits. As result, it were answered the questions: (Q1) What is the relative efficiency of membrane refurbishment solutions? (Q2) Which evaluated aspects benefit/penalize most the efficiency of membrane refurbishment solutions? (Q3) When do architectural membrane solutions constitute an efficient alternative to conventional ones for buildings refurbishment? With this thesis, it was demonstrated that architectural membrane refurbishment solutions are efficient alternatives to conventional reference ones in functional rehabilitation scenarios, especially when weight and reversibility/repeatability are important decision factors. In synthesis, refurbishment solutions with membranes allow buildings to adapt and update according to contemporary aspects of sustainability, being themselves efficient alternatives to conventional solutions, with contributions for a sustainable and innovative constructed environment. However, despite the increasing evolution of membrane materials in the recent past, there is still a long way to go so that they can be accepted and considered sustainable, also from the social and cultural point of view, especially in buildings for residential use. Finally, based on the conclusions drawn from this thesis, some clues are suggested for future developments.Fundação para a Ciência e a Tecnologia (FCT) e ao Fundo Social Europeu (FSE) pelo financiamento através da Bolsa de Doutoramento SFRH/BD/104891/2014, ao abrigo do Programa Operacional Potencial Humano (POPH) e do Ministério da Educação e Ciência (MEC). Também gostaria de agradecer às instituições de acolhimento: centro de investigação Lab2PT, Escola de Arquitetura da Universidade do Minho e ao centro de investigação Construct, Faculdade de Engenharia, Departamento de Engenharia civil da Universidade do Porto

Membrana divisória adaptável

Publicado em "Ciclo de wokshops fibrenamics 2012: livro de atas", ISBN 978-989-98468-2-1O objetivo deste artigo é apresentar as potencialidades das soluções de paredes divisórias interiores em membrana, nomeadamente em termos de flexibilidade de uso e adaptabilidade. A redução de peso nos elementos construtivos permite uma economia significativa de recursos materiais e energéticos, constituindo resposta relevante face às crescentes preocupações sobre as questões ambientais e à incerteza sobre a evolução da economia. Os problemas funcionais associados com as soluções leves, nomeadamente pouca massa térmica e isolamento acústico não são tão relevantes em divisórias internas como noutros elementos construtivos. A redução do peso nas divisórias interiores não implica incumprimento de exigências regulamentares em termos de desempenho funcional e mecânico, uma vez que apresentam poucos requisitos funcionais e são usualmente não estruturais. Este artigo aponta as vantagens das divisórias de membrana, comparando estas com as soluções convencionais.FCT (Fundação para a Ciência e Tecnologia) e COMPETE (Programa Operacional de Fatores de Competitividade

Divisórias leves em climas temperados

Este artigo pretende demonstrar que é possível utilizar membranas em paredes divisórias interiores e fachadas exteriores, mesmo em edifícios de habitação localizadas em regiões de clima temperado, como Portugal onde, por questões culturais e de desempenho funcional, se associa o elevado peso das soluções construtivas à qualidade da construção. Neste contexto, as propriedades das soluções leves, nomeadamente de membrana, deverão ser bem exploradas para que estas possam ser aceites. As soluções de membrana empregam pouco material e consegue ser ainda mais leves do que as convencionais soluções leves para divisórias - a mais comum é a de gesso com estrutura em perfis de aço. Em comparação com soluções convencionais pesadas, tais como a paredes de tijolo vazado, as membranas permitem uma fácil desconstrução / reutilização, além de uma menor energia incorporada especifica e apresentando outros indicadores demonstradores de um menor impacto ambiental. Na pele exterior, as membranas arquitectónicas podem ser utilizadas como sistemas passivos ou activos, para aquecimento (promoção de efeito estufa) e arrefecimento (sombreamento, ou mesmo de arrefecimento por evaporação). Mas a utilização de materiais leves é funcionalmente mais viável em climas invariavelmente quentes ou frios do que em climas temperados. Neste último contexto climático, as membranas apresentam problemas relacionados com a sua baixa capacidade de armazenamento térmico. No entanto, a pesquisa de novos materiais de membrana, com comportamento passivo e activo para a regulação térmica, permite estender suas potencialidades a paredes divisórias interiores com o objectivo de atender a demandas contemporâneas de conforto. Sistemas activos e/ou passivos podem ser usados para regular os ganhos térmicos - por exemplo, painéis radiantes e/ou de arrefecimento por evaporação, mas também para alcançar inércia térmica. Em estudos anteriores apresentados pelo primeiro autor foi estudada a capacidade de armazenamento térmico em pavimentos, usando materiais com mudança de fase (PCM). No presente estudo pretende-se mostrar alguns exemplos de aplicação de membranas em paredes divisórias interiores e exteriores em curso na Universidade do Minho, Guimarães.Fundação para a Ciência e Tecnologia (FCT) e COMPETE (Programa Operacional de Factores de Competitividade - Portugal