Total hemispherical emissivity of coated glass
Flat glass with low emissivity coatings is being used at an expanding rate by the European building industry for glazings with improved thermal insulation characteristics and comfort. A European intercomparison of angular total directional emissivity at 283 K was carried out by two metrological institutes (PTB and NPL), two laboratories which perform independent testing for the industry (TNO and Open University) and the R&D laboratory of a glass producer (Saint-Gobain). Measurements were performed on three types of coated flat glass, with normal emissivities of 0.14, 0.32 and 0.62. Before sending the samples to the participants, careful selection was made to ensure that the samples issued would not differ by more than 0.01 in normal emissivity. PTB, TNO and OU measured thermal radiation using broadband detectors, while NPL and SG measured spectral reflectance between 5 and 55 microns. All five reported results for angles up to 70 ; NPL, TNO and OU to 80 and TNO up to 85 .
Bibliographic Reference: EUR 14758 EN (1993) 51 pp., MF, ECU 4
Record Number: 199310558 / Last updated on: 1994-11-29
Original language: en
Available languages: en