Abstract:

In the design of power generation facilities, whether classified as ``indoor'' or ``outdoor,'' it often happens that the economic evaluation of noise control measures indicates the use of free-standing outdoor noise barriers as part of the overall facility acoustical design. Additionally, the facility buildings and components themselves often function as acoustical barriers. Whenever such barriers are to be modeled, approximations to classical barrier theory are common. The reality of actual facility arrangements, the limitations regarding placement of acoustical barriers, and the physical or economic constraints on barrier height usually mean that the size and positions of the barriers are not optimal. Furthermore, the presence of nearby reflective surfaces, the finite width of any given barrier, and the compounding effect of successive barriers or surfaces also necessitates adjustments to ideal barrier theory. This paper will discuss a number of particular cases commonly encountered and will recommend specific measures to be used to approximate the reality of actual situations. In addition, a general discussion will be presented which compares the mapping of sound levels beyond acoustical barriers as a function of whether the source is modeled as an idealized point source or as a more realistic distributed source. [See NOISE-CON Proceedings for full paper.]