Among six more essential demands for the European building directive (The Construction Products Directive 89/106/EEC), which are advanced for building materials and its goods, is protection against noise, economy of energy and heat insulation. In 2004 in Latvia a building norm for building acoustic has been adopted (Latvian Building Normative LBN 016-03), which advances high demands for sound insulation in buildings. The majority of buildings in Latvia, built before 60-ies, do not correspond to these demands. The Latvian building normative "Building acoustic", as one of sound absorbing materials offers porous material, which due to air friction in porous the sound energy transfers into heat. Foam gypsum is produced using gyps cohesive substance, manufacture technology of which is environment friendly and energy efficient. Foam gypsum like well known other gypsum products, gypsum paperboard as fire resistance material can be used. Nowadays using the technology of dry mineralization (Skujans et al, 2007) it is possible to obtain foam gypsum with different apparent density and pore dimensions. Such materials muffle sound in certain range of frequency; therefore it is possible to use them for manufacturing multilayer foam gypsum products for practical application. Besides foam gypsum posses good heat insulation properties too, which is essential for the development of environment protection problems. The acoustic properties of this porous material with changeable apparent density, foam gypsum is not enough investigated. It is possible to use foam gypsum in walls as sound and heat insulating material, as well as for interior decoration of premises.
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