The low-emissivity of coatings is camouflaged by wetting during rain, however, because in this case the sky is overcast, the heat loss is only insignificantly increased. It is known that the covering of dirt by weathering significantly decreases solar transmittance for all kinds of glazings. However it was shown that these coverings only insignificantly influence the emissivity of coatings beneath. This proves that the function of heat insulating glasses with low emissive coatings on the outer surfaces is not impaired by weathering if the coatings have sufficient ageing resistance to environmental attacks. Today, there are low-emissive coatings based on SnO2 on the market with high solar transmittance developed for position 3 of double heat-insulating glasses and coatings with reduced solar transmittance for position 2 of solar control glasses. Because the chemical and abrasive resistance of both types of coatings is better than that of untreated float glass, they can also be applied on outdoor surfaces. 10 refs.
Primary author(s): Glaser H J
Source: Glass Sci.Technol.