01829nas a2200169   4500008004100000050001500041245008200056210006900138260003900207520123000246100002401476700002201500700001801522700001901540700002501559856007501584       1998                        eng d  aLBNL-4135200aRapid field testing of low-emittance coated glazings for product verification0 aRapid field testing of lowemittance coated glazings for product   aClearwater Beach, Floridac12/19983 a<p>This paper analyzes prospects for developing a test device suitable for field verification of the types of low-emittance (low-e) coatings present on high-performance window products. Test devices are currently available that can simply detect the presence of low-e coatings and that can measure other important characteristics of high-performance windows, such as the thickness of glazing layers or the gap in dual glazings. However, no devices have yet been developed that can measure gas concentrations or distinguish among types of coatings. This paper presents two optical methods for verification of low-e coatings. The first method uses a portable, fiber-optic spectrometer to characterize spectral reflectances from 650 to 1,100 nm for selected surfaces within an insulated glazing unit (IGU). The second method uses an infrared-light-emitting diode and a phototransistor to evaluate the aggregate normal reflectance of an IGU at 940 nm. Both methods measure reflectance in the near (solar) infrared spectrum and are useful for distinguishing between regular and spectrally selective low-e coatings. The infrared-diode/phototransistor method appears promising for use in a low-cost, hand-held field test device.</p>1 aGriffith, Brent, T.1 aKohler, Christian1 aGoudey, Howdy1 aTurler, Daniel1 aArasteh, Dariush, K.  uhttps://facades.lbl.gov/publications/rapid-field-testing-low-emittance