Eco-efficiency of plasters for rehabilitation and new buildings

A review of the current state of art for air-lime, gypsum and earth based plasters for rehabilitation and new buildings, in terms of eco-efficiency, is presented. These mortars belong to Portuguese traditional architecture, responding to compatibility criteria most of the time. This factor, combined with a possible positive response to eco-efficiency evaluation, would bring interest for their application in rehabilitation as well as in new construction. To assess eco-efficiency of plasters, the considered factors are linked to the environmental impact of these products and to their contribution for occupants well-being. Some qualitative results concerning embodied energy for these mortars in a “cradle to gate” approach analysis are shown. The lack of a common, standardized and shared procedure for this evaluation seems an evidence, above all when the attempt of comparing results from different studies is made. Furthermore, common and specific characteristics mostly related to contribution for indoor comfort conditions are presented, as indicators of technical efficiency of those plasters. The potential for behaving as moisture regulators and passive removal materials not only affect users, but can also have an important role in energy savings. Lastly, durability is considered a key factor of eco-efficiency mainly to meet the purpose of minimising exploitation of raw materials. For this reason it is important to consider protective treatments or finishing system, for improving durability, always keeping in mind all the elements of the equation.publishersversionpublishe

Traditional and modern plasters for built heritage: Suitability and contribution for passive relative humidity regulation

Plasters have covered wide surface areas of buildings since antiquity, with a main purpose of indoor protection of the substrate on which they are applied. When no longer functional, they might require substitution with solutions that can combine compatibility with the substrate with the current need to mitigate building emissions. Indeed, plasters can contribute to lowering buildings’ energy demands while improving indoor air quality and the comfort of buildings’ users, as plasters can be used as passive regulators of relative humidity (RH). Hence, this study presents the relative-humidity-dependent properties of different plastering mortars based on clay, air lime, and natural hydraulic lime, and plastering finishing pastes based on gypsum and gypsum–air lime, in all cases tested using small size specimens. A cement-based plaster is also analysed for comparison. The clay-based plaster was the most promising material for RH passive regulation, and could be applied to repair and replace plasters in different types of buildings. Pastes based on air lime–gypsum could be applied as finishing layers, specifically on traditional porous walls. The sorption behaviour of cement plaster appeared interesting; however, its water vapour permeability was as expected, found to be the lowest, discouraging its application on historic walls.publishersversionpublishe

A study on hygrothermal conditions in intermittently heated or unheated bedrooms in southern Europe

PD/BD/150399/2019 PD/BD/135192/2017 UIDB/04378/2020Indoor hygrothermal parameters have an important role in the assessment of indoor air quality (IAQ) and comfort. In fact, the perception of air quality is strongly influenced by temperature (T) and relative humidity (RH). In Northern Europe, due to the severe climate conditions during winter, it is common to adopt continuous heating to guarantee sufficient thermal comfort in residential buildings. On the contrary, in Southern European countries, due to the specific climate, economy and culture, a permanent heating practice in winter is generally not adopted. Consequently, the indoor climate in Northern and Southern Europe is expected to be quite different, and this discrepancy should be taken into account when designing retrofit interventions aimed at improving indoor comfort and lowering energy demands. In particular, when studying the properties of interior coating materials, T is commonly set between 20-25 °C and RH in the range 33-75%. These are considered acceptable and common indoor conditions for continuously heated buildings, but they might be not representative of Southern European reality. For the present study, four residential buildings were chosen in the city of Lisbon. The indoor air T and RH were continuously recorded for one bedroom in each building during wintertime. The bedrooms are characterized by a floor surface of 7.5-10 m2, the occupancy of one person during an average of eight hours, natural ventilation and the presence of one window North/Northwest oriented and with manually-regulated shading. All rooms were monitored under operational conditions, with users adopting intermittent heating (room heaters) or no heating at all. The main differences between the case studies concern the floor where the apartments are located and the constructive characteristics of the buildings. The indoor hygrothermal conditions obtained in the monitoring campaign are discussed in this paper and indoor thermal comfort is evaluated. Finally, despite the differences between the case studies, an approximation of the overall indoor T and RH fluctuations is provided.publishersversionpublishe

Eco-Efficient Coatings for Healthy Indoors: Ozone Deposition Velocities, Primary and Secondary Emissions

Volatile organic compounds (VOCs) and ozone (O3) are harmful pollutants present in indoor air. Indoor concentrations of VOCs are typically higher than outdoors, due to the presence of indoor sources like building materials and ozone-surface reactions. The study aims to identify and quantify the ozone reactivity and primary and secondary emissions of different indoor coatings. The coatings selected for the study were three gypsum-based plastering mortar, with and without the addition of a bio-waste from Acacia dealbata (raw bark, BA, and bark heated at 250°C, BA250), two clay plasters (one with sand and the other with seashells as additional aggregate), applied both as basecoat and topcoat (on drywall), and one un-coated drywall. All the products tested had ozone deposition velocities that would reduce the indoor ozone concentration meaningfully if implemented in a real indoors, contributing to the improvement of indoor air quality. The gypsum-based plaster shows the lowest ozone deposition velocity, but also the lowest primary and secondary emissions. The addition of bark, either BA or BA250, increased by 50% the ozone deposition velocity of the coating but also increased primary and secondary emissions by 80% (BA) and 200% (BA250), with methanol (m/z 33.030) accounting for about 60% of the increase. The addition of crushed seashells to the formulation of the clay-based plasters lowered the secondary emission yields (102% and 120% respectively, when applied as base and topcoat)

Horta da Escola

Orientadora: Valéria Aparecida BressianiniMonografia (especialização) - Universidade Federal do Paraná, Setor Litoral, Curso de Especialização em Alternativas para uma Nova EducaçãoInclui referênciasResumo: O presente trabalho apresenta como proposta o desenvolvimento de um Projeto de implnataçao de horta escolar que surgiu mediante discussões com os alunos, por meio de rodas de conversa, refente a quantidade de materiais reciclaveis que são descartados no meio ambiente e a dúvida quanto às medidas de presenvação ambiental. Diante das discussões que aconteceram pautadas pela metodologia de Paulo Freire, com a realização dos círculos dialógicos, o coletivo decidiu implantar uma horta no espaço escolar utilizando garrafas pet, na montagem dos canteiros. O projeto terá continuída no ano letivo de 2023, com reflexões sobre alimentação saudavel e o contato dos alunos com a natueza, além da produção dos vegetais que serão consumidos pelos próprios alunos

Effect of different fractions and contents on the relative humidity dependent properties

Funding Information: The authors would like to thank the National Laboratory for Civil Engineering of Portugal (LNEC) for the laboratory equipment and the support provided through the projects REuSE - Wall coverings for Rehabilitation: Safety and Sustainability; the Departments of Civil Engineering and Chemistry of the NOVA School of Science and Technology of the NOVA University of Lisbon, and the Department of R&D of SIVAL-Gessos Especiais, Lda. Publisher Copyright: © 2023Hemihydrate gypsum is a very eco-efficient binder. Gypsum plasters were commonly used in the past and should be still chosen nowadays for being an eco-efficient choice. However, their hygroscopicity and contribution to act as moisture buffer are not very high. The present study analyses the hygrothermal behaviour of mortars based on gypsum and modified with the addition of residual biomass of A. dealbata, an invasive species in Portugal. Five different fractions of the plant were tested as additions for mortars, at incorporation levels of 5% and 10% by volume, with the purpose of enhancing the moisture buffering of the plasters without jeopardizing other properties. The study found that the addition of A. dealbata increases their hygroscopic behaviour. In some cases (bark fraction) the Moisture Buffering Value of the reference mortar is triplicated, and the behaviour is comparable with high hygroscopic plasters as clay-based ones. However, biological colonization must be controlled.authorsversionpublishe

Ethics in medical research and the essential bureaucracy of ethics committees: an experience report

Since October 1996, Brazil has a new regulation on research involving human beings, it is the Resolution nº 196 of 1996 of the National Health Council, instance in which the National Research Ethics Commission and the Ethics Committees were created in Research – EC. This resolution says that each and every research project, in any area, involving human beings must contain an analysis of ethical aspects – carried out by the researcher himself – and be approved by the Research Ethics Committee. Research involving human beings is understood to be that which, individually or collectively, directly or indirectly involves human beings, in their entirety or parts of them. This article reports the difficulties in developing a research project that will later be approved by an EC, but with an emphasis on why these difficulties exist

Can different stages of leprosy treatment influence the profile of oral health? Oral status in leprosy

The aim of study was to evaluate the oral health status, salivary flow and halitosis among individuals diagnosed with leprosy as compared with healthy subjects. A sample of 160 individuals was allocated into four groups, as follows: (G1) individuals with complete leprosy treatment; (G2) individuals diagnosed with leprosy and under multi-drug therapy; (G3) individuals diagnosed with leprosy not yet under treatment; and (G4) healthy individuals. Then individuals were submitted to periodontal clinical examination (visible plaque index, bleeding index, depth of probing and clinical attachment level); DMFT index (decayed-missing-filled teeth index); evaluation of salivary flow and halitosis using a halimeter equipment (Interscan Corp, Chatsworth, CA, USA). The data were analyzed using Kruskal-Wallis and chi-square tests. The mean DMFT was found to be higher than 6.6, which is considered very high, with no significant difference between groups (P>0.05). As for salivary flow, 76.2% of the subjects presented normal flow rates, while 10% and 13.7% showed low and very low salivary flow rates, respectively, with hyposalivation being mostly observed in Groups 1 and 2. The highest prevalence of noticeable odor was found in healthy individuals (G4), and the most prevalent periodontal diagnosis was gingivitis (63.1%) in Group 3 (individuals with leprosy not yet under multi-drug therapy) followed by periodontitis (25%) in Group 1 (individuals who had completed leprosy treatment). It was observed that individuals with a history of leprosy present poor oral health similar to that of systemically healthy individuals