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Research Project
ESTUDO EXPERIMENTAL E NUMÉRICO DO COMPORTAMENTO DE UM MATERIAL INTUMESCENTE NA PROTECÇÃO PASSIVA DE ELEMENTOS ESTRUTURAIS SUBMETIDOS A INCÊNDIO
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Caracterização da decomposição térmica e formação carbonosa de tintas intumescentes
Publication . Mesquita, L.M.R.; Piloto, P.A.G.; Magalhães, F.; Pimenta, Joana; Vaz, M.A.P.
Este trabalho apresenta um estudo dos mecanismos de decomposição e de intumescência de
duas tintas comerciais de base aquosa. São apresentados resultados experimentais, obtidos
através de termogravimetria e num calorímetro de cone. Os resultados do primeiro teste
permitem aferir a variação da perda de massa com a temperatura, para distintas taxas de
aquecimento e, considerando que as reacções químicas são descritas pela equação de
Arrhenius, é apresentado o método de cálculo dos parâmetros cinéticos, energia de activação
e factor pré-exponencial, comparando diferentes métodos cinéticos. Os testes realizados no
calorímetro de cone, especificando um fluxo de calor radiante, permite quantificar a
variação da camada intumescente e a evolução da temperatura no substrato.
Caracterização do comportamento e das propriedades termofísicas de tintas intumescentes
Publication . Mesquita, L.M.R.; Piloto, P.A.G.; Vaz, M.A.P.
Este trabalho apresenta um estudo experimental e numérico efectuado em placas de
aço protegidas com tinta intumescente e sujeitas a um fluxo de calor radiante proveniente de
um calorímetro de cone. As placas de aço são pintadas na face exposta ao calor com diferentes
espessuras de protecção e sujeitas a diferentes fluxos de calor. A variação da temperatura
em ambas as faces da placa é obtida através de termopares do tipo k soldados à placa. Os
resultados permitem caracterizar o comportamento térmico do intumescente, estimar a expansão
volumétrica e a taxa de perda de massa. Numericamente é utilizado o MDF para resolver
o problema inverso e determinar a condutividade térmica efectiva e a temperatura à superfície
do intumescente.
An experimental study of intumescent fire protection coatings
Publication . Mesquita, L.M.R.; Piloto, P.A.G.; Vaz, M.A.P.
The use of intumescent coatings plays an important role in the fire protection of structural
elements. When submitted to elevated temperatures an intumescent coating undergoes
thermochemical reactions that promote a higher thermal protection. To evaluate the behaviour of
an intumescent coating, a set of experimental tests made on coated steel plates are performed in a
cone calorimeter. These tests are performed with different heat fluxes and intumescent
thicknesses. A simple and an advanced model, based in the Finite Difference Method, are
presented and applied to determine the intumescent surface temperature evolution, considering
the initial thickness and the intumescence variation.
The intumescence effective thermal conductivity is estimated by solving the inverse heat transfer
problem, considering the temperature in the steel equal to the experimental measured values.
When the intumescence thickness variation is taken into account in the numerical model a higher
thermal conductivity is expected, when compared with the constant thickness model.
Decomposition of intumescent coatings: comparison between numerical method and experimental results
Publication . Mesquita, L.M.R.; Piloto, P.A.G.; Vaz, M.A.P.; Pinto, T.
An investigation of two different intumescent coatings used in steel fire protection has been performed to evaluate their efficiency. A set of experimental
tests is presented. They were conducted in a cone calorimeter, considering different thicknesses and heat fluxes. Among other
quantities, the steel temperature and the intumescence thickness variation were measured. A numerical model for the paint decomposition is
also presented. Based on the intumescence experimental value, the model is able to provide a reasonably good prediction of the steel temperature
evolution.
Decomposition of intumescent coatings: comparison between numerical method and experimental results
Publication . Mesquita, L.M.R.; Piloto, P.A.G.; Vaz, M.A.P.; Pinto, T.
Passive fire protection materials insulate steel structures from the effects of the elevated
temperatures that may be generated during fire. They can be divided into two types, non-reactive, of
which the most common types are boards and sprays, and reactive, being intumescent coatings an
example. They are available as solvent or water based systems applied up to approximately 3[mm].
One problem associated with the use of such systems is the adhesion of the charred structure to the
steel element during fire and upon it. It is very important that the char remains in the steel surface to insure the fire protection.
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
Funding Award Number
SFRH/BD/28909/2006