Sound Transmission Class (STC) Of Fixedwindow Glazing Inwarm Humid Environment
Acoustic property of glass material for window in term of sound transmission class (STC) within a warm humid environment of Indonesia is studied. Earlier research, books, and glass manufacturer’s manual informs STCs of glass material. Nevertheless, the use of glass in buildings in warm humid air may cause a decrease or increase in STC. The fluctuation of STC is estimated to be affected by warmer air. In the case of developing country such as Indonesia, limited knowledge and awareness of Indonesians may also play a role in different installation techniques and supporting materials used that may create variation in STCs compared to the manual or standard. A series of laboratory test was conducted to see STCs of Indonesian glass in a conditioned temperature higher than is outlined by ASTM. The relative humidity was also set to represent relative humidity of Indonesia. Composite wall testing method by ASTM E90-09 was employed for fixed window glass. The tests informs that STC of Indonesia glass slightly lower to that of UK glass, i.e. Pilkington. Variety in glass types (transparent ordinary float/flat glass, laminated, tempered, and frosted glass) did not produce significant STCs variation, which is 1-2 only. Higher room temperature of 31-32C also produced no significant STCs, which is 1 only. This may become a new reference that temperature variation in test room do not play significant role as long as the temperature has no impact on molecular deformation of the test specimen. It is concluded that the most decisive factor of glass material used for fixed window system is density, which for these test specimens remain in approximately 25 kg/m2. Further investigation on molecular formation of glass material and study on open window glass is recommended.
Keywords- glass window, sound transmission class, warm humid environment