Soiling of building envelope surfaces and its effect on solar reflectance – Part III: Interlaboratory study of an accelerated aging method for roofing materials

Abstract

REVISED DRAFT 2015-7-7 Soiling of building envelope surfaces-Part III

Effects of soiling and weathering on the albedo of building envelope materials: Lessons learned from natural exposure in two European cities and tuning of a laboratory simulation practice

“…The laboratory exposure produces in all the spectral regions a lower standard deviation than low sloped exposure both in Rome and Milan and of the same order of magnitude of the tilted exposure, with the interquartile range within 0.02 and the maximum standard deviations of less than 0.03. The standard deviations of the repeatability and reproducibility of the ASTM D7897-18 protocol, respectively equal to 0.008-0.015 and 0.022-0.036, are less than the maximum standard deviation for low sloped exposure ( Figure 9) and less than the difference between exposure campaigns at the same site (Figure 4) [59].…”

“…Thus, neither ASTM D7897-18 nor the laboratory exposure of this study are referred to as accelerated aging. The repeatability and reproducibility of the ASTM D 7897-18 protocol were tested in a nine-participant interlaboratory study [59]. The repeatability standard deviation ranged from 0.008 to 0.015, while the reproducibility standard deviation ranged from 0.022 to 0.036.…”

The Solar Reflectance Index as a Tool to Forecast the Heat Released to the Urban Environment: Potentiality and Assessment Issues

“…Entering into details, a calibrated aqueous soiling mixture of dust minerals, black carbon, humic acid, and salts is sprayed onto 10 cm × 10 cm preconditioned coupons of the tested materials, which are then subjected to cycles of ultraviolet radiation, heat, and water in a commercial weatherometer. The method proved to be easy and fast to perform, repeatable, and above all able to reproduce the reflectance obtained in a wide range of naturally exposed roofing products [30,31].…”

“…Moreover, randomly variable conditions are always possible in the weathering sites due to variations in meteorology and air pollution, and this may affect significantly the results. The solution seems to be provided by a recently developed laboratory method for accelerated ageing [30,31]-already a standard test method as ASTM D7897 [32]-which can condense into three days the three-year long process of natural ageing used by the CRRC to rate roofing products sold in the U.S. Entering into details, a calibrated aqueous soiling mixture of dust minerals, black carbon, humic acid, and salts is sprayed onto 10 cm × 10 cm preconditioned coupons of the tested materials, which are then subjected to cycles of ultraviolet radiation, heat, and water in a commercial weatherometer.…”

Coberturas Verdes E Convencionais E a Mitigação Das Ilhas De Calor Urbano

“…Já o trabalho conduzido por um grupo de pesquisadores dos Estados Unidos, França, Itália e Canadá (SLEIMAN et al, 2014;SLEIMAN et al, 2015), destaca o tema envelhecimento e sujeira das coberturas e sua inluência na reletividade dessas superfícies. Esse grupo salienta que a alta reletividade das coberturas pode diminuir a energia para resfriamento do edifício, ajuda na mitigação dos efeitos das ICUs e do aquecimento global.…”