Solar reflectivity or … The most well-known type of reflective surface is the "cool roof". Oxidized: 0.8-0.9: 0.8-0.9: 0.7-0.9 Stainless: 0.35: 0.2-0.9: 0.1-0.8: Tin … Another method to dull the surface is to zinc phosphate treat or phosphatize a newly galvanized part. These processing techniques will not produce a galvanized coating with 12% to 18% reflectivity in all instances so they should only be used after agreement with your customer. TruZinc® Steel, a galvanized steel sheet manufactured by Steelscape, provides a metallic coating of zinc over a steel base. Another possible method of dulling the surface is to dip the parts in a 1% nitric acid solution for 90 seconds. Figure 4. 6881 South Holly Circle, Suite 108 The dependence of reflectance on the wavelength is called a reflectance spectrum or spectral reflectan… A newly galvanized part with the normal pure zinc layer on the outside has a natural reflectivity of over 70% in the visible range. In the early 1970's, there were four separate power companies/agencies who demanded galvanized products be dulled, that is, their reflectivity needed to be reduced to 12% to 18% before installation in the field. These primers can be spray applied in the field. The reflectance of the surface of a material is its effectiveness in reflecting radiant energy. Anyone making use of this information assumes all liability arising from such use. The emissivity coefficient - ε - indicates the radiation of heat from a 'grey body' according the Stefan-Boltzmann Law, compared with the radiation of heat from a ideal 'black body' with the emissivity coefficient ε = 1. 13-4 provides such information for the most widely used materials. 0.4-0.6 Polished Sheet: 0.35: 0.25: 0.1 Molten: 0.35: 0.25-0.4: n.r. The SR value is a number from 0 to 1.0. © 2020 American Galvanizers Association. High reflectivity in the visible is of course the chief property required of metals for mirror applications, and Fig. This question was first asked many years ago in the electrical transmission line business when electrical towers were erected in rural/wilderness areas. Centennial, Colorado 80112, Phone: 720.554.0900 Total reflectance of Invar and stainless steel samples. A third method is to apply a primer coat to the surface of the galvanized steel; there are a number of commercially available primer coats that will darken the surface adequately. These processing techniques will not produce a galvanized coating with 12% to 18% reflectivity in all instances so they should only be used after agreement with your customer. Privacy Policy • Quick Links • TSR or Total Solar Reflectance is a figure expressed as a percentage between 0 and 100% that rates a products ability to reflect solar energy back into the atmosphere. Reflective surfaces can deliver high solar reflectance (the ability to reflect the visible, infrared and ultraviolet wavelengths of the sun, reducing heat transfer to the surface) and high thermal emittance (the ability to radiate absorbed, or non-reflected, solar energy). Menu • Was this answer helpful? Fax: 720.554.0909, General Information Reflective surfaces are a form of geoengineering.. Total reflectance of various commercial and household blackout and baffling materials. The use of steel that is high in silicon content will also give a coating that is nearly all intermetallic and, therefore, dull gray in appearance. A number of methods have been suggested to accomplish the task of dulling the bright surface of newly galvanized parts. Solar Reflectivity (R) & Solar Reflectance Index (SRI) by Color. The information provided herein is not intended as a representation or warranty on the part of the AGA. | In commonly employed front surface mirrors, resistance to mechanical scratching (of Au, Ag, Cu, Al), oxidation (of Al), and tarnishing (of Ag) are additional concerns.