ABSTRACT
This paper presents values of Solar Heat Factor (SHF) and Visible Light Transmittance (VLT) to sixteen types of translucent glasses and to six types of translucent polycarbonates, used in Brazil. Tests were performed in spectrophotometer, with integrative sphere, for normal incidence, resulting curves of transmission and reflection for a spectral range from 300 to 2000 nm. From the integration of the obtained value curves at each wavelength, weighted according to the standard solar spectrum, were calculated the values of transmittance, reflectance and absorptance, for the total spectrum and for the regions of ultraviolet (UV), visible and infrared (IR) separately. Translucent colorless glasses tested present transmittance in the region of infrared below visible, resulting a relation between the light gain and heat gain equals to or greater than one, presenting that is a good indication to use this glass type in hot climates. Translucent colored glasses have SHF values lower than colorless glass of same type, with VLT even lower, being its use more related to esthetics issues than care with heat gains. All tested polycarbonates transmit a very small portion in UV, and only the green alveolar transmits more in visible light than in IR, wherein the ratio between the light gain and heat gain of these materials is low, except green and colorless alveolar. Except colorless alveolar, all have high absorption of solar radiation, indicating materials with high solar heat gain and high surface radiant temperature when exposed to the sun, which can cause localized discomfort.
Keywords
translucent glass; translucent polycarbonates; Solar Heat Factor; Visible Light Transmittance
