Análise térmica de um forno de resistência ao fogo

A classificação de produtos de construção em relação ao comportamento ao fogo é determinada pelas normas vigentes, utilizando um forno com curvas de incêndio normalizadas, como são exemplo as curvas de padrão 150 834, ASTM E119, hidrocarbonetos, etc. Neste trabalho pretende-se efectuar uma análise técnica do volume interno do forno de resistência ao fogo, efectuando a medição de temperaturas em l6 pontos geometricamente distribuídos, com a utilização de termopares de placas. Estas medições deverão ser comparadas com os resultados obtidos por simulação numérica, utilizando as equações de conservação de energia, de momento e de massa, associados a modelos de turbulência e de radiação

Thermal analysis in fire-resistance Furnace

Fire resistance rating of building construction elements is defined under fire-resistance test furnace. The geometry and shape of fire-resistance furnaces is not defined by any prescriptive document, being necessary to comply thermally with specified nominal fire curves, such as ISO 834 or hydrocarbon [1,2]. This research work intends to measure temperatures inside furnace volume, using sixteen plate thermocouples to compare average temperature in four planes. Those planes are compared with reference thermocouple which is responsible for controlling furnace operation, see figure 1. Three tests were performed, the first two running with ISO 834, during 45 minutes and the last one running with hydrocarbon curve, during 30 minutes. Experimental results demonstrate that relative temperature differences are smaller than 30 % in the initial test stage, being smaller than 5 %, after 500 [s] until the end of the tests. The numerical simulations were performed using Fluent CFD, using the structured finite volume mesh method. The Eddy Dissipation Model (EDM) was used for chemical species transport and reacting flow. The governing equations for mass, momentum and energy were solved for the three dimensional unsteady incompressible flow, with radiative heat transfer and turbulence model. The numerical results agree well with experimental results, being the relative temperature difference smaller than 5% for each nominal test. Numerical simulation also reveals the localized effect of each burner.The authors acknowledge the financial support from the Portuguese Science and Technology Foundation, under the reference project PTDC/EME-PME/64913/2006

Estudo do comportamento ao fogo dos CFRP’s – sistemas passivos de proteção

Com o aumento da utilização dos materiais compósitos (FRP) são inevitavelmente encontrados novos problemas e desafios. De entre esses problemas, existem preocupações legítimas em relação ao seu comportamento quando expostos ao fogo. No caso de exposição direta ao fogo, é recomendável que os FRP sejam aplicados com medidas adicionais de prevenção. É objetivo deste trabalho estudar o comportamento dos materiais compósitos à base de fibras de carbono (CFRP) ao fogo. Os materiais utilizados foram a manta e o laminado de fibra de carbono. Para tal é apresentada uma campanha de ensaios com amostras de provetes de betão de dimensão 100×100×40 mm. O CFRP é colado na superfície dos provetes com resina epoxídica exposta à ação térmica. As medidas passivas estudadas neste trabalho são destinadas a impedir a ignição do fogo e a diminuir o impacto dos incêndios através de mecanismos que não necessitam de intervenção humana ou automatismos. Dependendo do tempo desejado para a resistência ao fogo, podem aplicar-se diversos materiais de proteção, no nosso estudo foi analisados o gesso cartonado e tintas intumescentes. A superfície reforçada é exposta à ação de dois fluxos de calor por radiação, 35 kW/m2 e 75 kW/m2, provenientes de um calorímetro de perda de massa. A evolução da temperatura é avaliada através de termopares colocados entre as superfícies de ambos os materiais permitindo uma análise da influência destes materiais de proteção na capacidade de reforço estrutural dos CFRP quando submetidos a temperaturas elevadas. Após os ensaios conclui-se que a placa de gesso tem um melhor desempenho quer para a manta quer para o laminado do que a tinta intumescente.info:eu-repo/semantics/publishedVersio

CFRP fire behaviour - passive protection system

The technique of reinforcing concrete structures by means of bonding composite fibre reinforced polymers (FRP) has been applied in the construction industry. There are several examples of application of these materials in bridges and in buildings, both in new construction and rehabilitation and/or strengthening of damaged structures. With the increasing use of FRP new problems and challenges are inevitably found. Among these subjects, there are legitimate concerns about the behaviour of FRP materials when exposed to fire action. It is the aim of this work to analyse the behaviour of composite materials exposed to fire, in particular composite materials based on carbon fibres (CFRP). Therefore a set of tests on 100 × 100 × 40 mm concrete specimens with CFRP are to be analysed using the test method recommended by EN ISO 13927. The CFRP sheet is glued on the top surface of the specimens using epoxy resin and exposed to thermal action. The surface of the reinforcement system is exposed to the action of different radiative heat fluxes, from 35 kW/m2 to 75 kW/m2, from a cone calorimeter and changes in temperature are determined by thermocouples placed between the surfaces of both materials, and the material heat release rate by the use of a thermopile. The influence of passive fire protection systems on the CFRP fire reaction is analysed considering different fire protection materials (gypsum boards, ceramic fibre sheets and intumescing paints). The temperature variation during the period of thermal exposure is measured across the surface of the different material layers, allowing to assess the influence of these fire protection materials to the CFRP structural reinforcement capabilities at elevated temperatures.The authors wish to acknowledge Reconco Company for the supply of plasterboard.info:eu-repo/semantics/publishedVersio

Medication dispensing system architecture

Non-adherence of prescribed medication is a global problem that a ects many people. There are many factors related to this problem that contributes to further increase the problem and impact in a patient's life. It is proposed a system to assist in the management of medicine and the communication with carers. The system has many components that include mechanical components, electrical components and management system, and servers. It is intended to o er a system that can help reduce the non-adherence factors and the consequences in the life of the patients and their carers.info:eu-repo/semantics/publishedVersio

CFRP fire behaviour – passive fire protection materials

The technique of reinforcing concrete structures by means of bonding composite fibre reinforced polymers (FRP) has been applied in the construction industry. There are several examples of application of these materials in bridges and in buildings, both in new construction and rehabilitation and/or strengthening of damaged structures. With the increasing use of FRP new problems and challenges are inevitably found. Among these subjects, there are legitimate concerns about the behaviour of FRP materials when exposed to fire action. It is the aim of this work to analyse the behaviour of composite materials exposed to fire, in particular composite materials based on carbon fibres (CFRP). Therefore a set of tests on 100 × 100 × 40 mm concrete specimens with CFRP are to be analysed using the test method recommended by EN ISO 13927. The CFRP sheet is glued on the top surface of the specimens using epoxy resin and exposed to thermal action. The surface of the reinforcement system is exposed to the action of different radiative heat fluxes, from 35 kW/m2 to 75 kW/m2, from a cone calorimeter and changes in temperature are determined by thermocouples placed between the surfaces of both materials, and the material heat release rate by the use of a thermopile. The influence of passive fire protection systems on the CFRP fire reaction is analysed considering different fire protection materials (gypsum boards, ceramic fibre sheets and intumescing paints). The temperature variation during the period of thermal exposure is measured across the surface of the different material layers, allowing to assess the influence of these fire protection materials to the CFRP structural reinforcement capabilities at elevated temperatures.info:eu-repo/semantics/publishedVersio

Comportamento ao fogo dos CFRP – sistemas passivos de proteção

Os materiais compósitos de matriz polimérica reforçada com fibras (FRP) têm vindo a ser continuadamente aplicados na indústria da construção. Apesar das inúmeras vantagens que os FRP apresentam tais como rapidez e facilidade de execução, leveza e resistência à corrosão têm como desvantagem a sua resistência ao fogo limitada pela instabilidade da resina quando exposta a elevadas temperaturas. O trabalho desenvolvido pretende dar um contributo no conhecimento de sistemas passivos à base de placas de gesso, mantas de fibras cerâmicas e tinta intumescente na proteção ao fogo de mantas de fibras de carbono (CFRP) coladas em provetes de betão. O comportamento ao fogo do CFRP é analisado através de análises termogravimétricas (TGA) e de calorimetria diferencial de varrimento (DSC). A influência da proteção ao fogo dos CFRP é realizada através de ensaios experimentais conduzidos num calorímetro de perda de massa, considerando diferentes fluxos de calor por radiação.info:eu-repo/semantics/publishedVersio