Variation of color parameters in ceramic and concrete tiles due to natural weathering
DOI:
https://doi.org/10.46421/encac.v17i1.3745Keywords:
color parameters, solar absorptance, thermal performance, roof tilesAbstract
In the construction industry, color selection for the building envelope is often driven primarily by aesthetic considerations. However, due to the surface properties of materials related to solar absorption, the colors of buildings also influence their thermal performance. The main objective of this study was to analyze the effects of natural aging on ceramic and concrete tiles in terms of their color parameters and surface temperature, both of which are associated with variations in solar absorptance. To achieve this, 25 tiles were selected and exposed to outdoor weather conditions for a period of 24 months in a natural aging station located in São Carlos, SP. It was found that the color parameter most correlated with solar absorptance (αsolar) is luminance (L*), and in general, higher luminance (L*) values correspond to lower solar absorptance (αsolar) of the tile. In addition, high solar absorptance (αsolar) values are associated with low luminance (L*) values, which somewhat explains the often mistaken visual association between "light" colors and their low absorption of solar radiation. The tile with the highest initial luminance (L*) and lowest initial solar absorptance (αsolar) experienced the greatest percentage change in solar absorptance after exposure. However, despite being the most affected by natural degradation, it continued to exhibit the lowest surface temperatures of all the selected samples even after 24 months of weathering. Therefore, it can be concluded that the sample with the lowest percentage of degradation over time is not always the most recommended choice when considering thermal comfort in buildings. Regarding the colors, it was not possible to determine a trend line for changes in a*, b*, C and h parameters over 24 months of exposure to weathering for the 25 tiles selected in this study. In conclusion, proper color specification and control of the optical properties of building envelope materials are cost-effective and efficient strategies for controlling thermal gains in a building.
References
ABNT. ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 15220: Desempenho térmico de edificações. Rio de Janeiro. 2005.
ABNT. ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 15575: Edificações habitacionais - Desempenho. Rio de Janeiro. 2021
AKBARI, H.; BERHE, A.; LEVINSON, R. Aging and weathering of cool roofing membranes. Report LBNL-58055, 2005.
ALCHAPAR, N. L.; CORREA, E. N. Aging of Roof Coatings: solar reflectance stability according to their morphological characteristics. Construction and Building Materials, v. 102, p. 297–305, 2016.
ARAUJO, Ana Carolina Hidalgo. Absortância solar e o envelhecimento natural de telhas expostas ao tempo. 2022. Dissertação (Mestrado em Arquitetura, Urbanismo e Tecnologia) - Instituto de Arquitetura e Urbanismo, Universidade de São Paulo, São Carlos, 2022. doi:10.11606/D.102.2022.tde-06062022-143613. Acesso em: 2023-04-13.
ARAUJO, A. C. H.; DORNELLES, K. A. Estação de envelhecimento natural para análise de degradação da absortância de telhas e monitoramento de temperaturas superficiais. Ambiente Construído, Porto Alegre, v. 22, n. 2, p. 247-267, abr./jun. 2022. http://dx.doi.org/10.1590/s1678-86212022000200603
AMERICAN SOCIETY FOR TESTING AND MATERIALS. D2244-15: Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates. West Conshohocken, 2015.
AMERICAN SOCIETY FOR TESTING AND MATERIALS. E903: standard test method for solar absorptance, reflectance and transmittance of materials using integrating spheres. West Conshohocken, 2020a
AMERICAN SOCIETY FOR TESTING AND MATERIALS. G173-03: standard tables for reference solar spectral irradiances: direct normal and hemispherical on 37º tilted surface [S]. West Conshohocken, 2020b.
BRETZ, S.; AKBARI, H. Long-term performance of high-albedo roof coatings. Energy and Buildings, v. 25, n.2, p. 159-167, 1997.
CHENG, M.-D.; MILLER, W.; NEW, J.; BERDAHL, P. Understanding the long-term effects of environmental exposure on roof reflectance in California. Construction and Building Materials, v. 26, p. 516-526, 2012.
INMETRO. Comitê Brasileiro de Iluminação (CIE Brasil). INMETRO, 2020. Disponível em: http://www.inmetro.gov.br/ciebrasil/origem.asp. Acesso em 10 de fev. 2022.
MAESTRI, A. Avaliação da refletância solar em coberturas no Campus da Universidade Federal de Santa Catarina. Florianópolis: Dissertação de mestrado - UFSC, 2017
MASTRAPOSTOLI, E.; SANTAMOURIS, M.; KOLOKOTSA, D.; VASSILIS, P.; VENIERI, D.; GOMPAKIS, K. On the ageing of cool roofs: Measure of the optical degradation, chemical and biological analysis and assessment of the energy impact. Energy and Buildings, v. 114, p. 191-199, 2016.
MORINI, E.; CASTELLANI, B.; NICOLINI, A.; ROSSI, F.; BERARDI, U. Effects of aging on retro-reflective materials for building applications. Energy and Buildings, v. 179, p. 121-132, 2018.
PEREIRA, C. P. A. A cor no desenho industrial: fundamentos para o projeto cromático de produtos. 2000. 183p. Dissertação (Mestrado em Arquitetura e Urbanismo) - Curso de PósGraduação em Arquitetura e Urbanismo, Universidade de São Paulo, São Paulo. 2000
SHIRAKAWA, M.A., SILVA Junior, J.A., MARQUES, S.A.V., JOHN, V.M. Superfícies frias Avaliação da refletância em quatro cidades brasileiras após um ano de envelhecimento natural. In: ENCONTRO NACIONAL DE TECNOLOGIA DO AMBIENTE CONSTRUÍDO, 17., 2018, Foz do Iguaçu. Anais... Porto Alegre: ANTAC, 2018.
SILVA, I. Estudo de durabilidade de pinturas "frias" e convencionais expostas ao envelhecimento natural. Dissertação (Mestrado) São Paulo: Escola Politecnica da Universidade de São Paulo, USP, 2017.
SILVEIRA, Luciana Martha. Introdução à teoria da cor. 2. ed. – Curitiba: Ed. UTFPR, 2015.
SYNNEFA, A.; SANTAMOURIS, M.; APOSTOLAKIS, K. On the development, optical properties and thermal performance of cool colored coatings for the urban environment. Solar Energy, v. v.81, p. p.488-497, 2007
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2023 ENCONTRO NACIONAL DE CONFORTO NO AMBIENTE CONSTRUÍDO
This work is licensed under a Creative Commons Attribution 4.0 International License.
