Reduction of noise levels using foam polystyrene concrete walls and plaster 1. In Regulation N 6 - 26/06/2006 (The Public Newspaper (an Official Gazette) issue 58 -  18/07/2006) are normalized limits of the equivalent noise levels of 30 to 60 dB (A).  Requirements for the lowest levels of 30 dB (A) full-time concern for rooms in hospitals and  at night for residential rooms, sleeping rooms in dormitories and kindergardens, rest homes  and hotel rooms.  2. In Regulation N 4 - 27/12/2006 (The Public Newspaper (an Official Gazette) issue -  19/01/2007) to reduce harmful noise through Sound insulation of buildings in their design  and implementation in Annex 2 to art. 19 is normalized minimum airborne sound insulation  from the surrounding structures and elements of buildings.  TABLE1  A comparison of the two regulations leads to two main conclusions: - hospitals, residential buildings, hotels and social facilities have been built in neighborhoods        with relatively low levels of external noise (60 dB (A)); - as usual equivalent noise in cities with populations over 50 thousand inhabitants is 76-80 dB  (A) and even now it is lower, urban development will be arguments to these levels is still reasonable  in the design process to for external walls to reduce noise in buildings up to 30-35 dB (A).  3. Recommendations for selection of external walls  Early in the 20th century R. Berger found the dependence of sound insulation properties of  building materials from its mass. The more severe the more material greatly reduces switching noise.  Not coincidentally "absolutely quiet rooms are constructed of lead walls or extremely heavy concrete.  Naturally in large-scale development, they are irrelevant - extremely expensive and heavy, with a  negligible thermal insulating ability.   Subsequent numerous studies show that the reduction of sound levels can be achieved through  the use of composite material.with different density and structure. Very suitable for this purpose are  porous cellular concrete.  © 2011 Всички права запазени за ДАЙ ВАР ЕООД | Уеб дизайн и изработка DX Computers Ltd.