building a software for prediction of noise propagation in a complex condition (indoor to outdoor)

original article     the aim of this study was to design and build a software for noise propagation prediction (indoor and from indoor to outdoor spaces) which is being commonly used in industry.  in this regard, firstly a mathematical complex model was created based on existing relationships about noise propagation in indoor spaces and transmission through the walls and propagation in outdoor spaces. to model noise propagation from indoor to outdoor, the function of this model is based on meshing the wall which is effective on outdoor receiver point. by analyzing the required inputs and outputs and designing and documenting the process algorithm, the mathematical model was created and the software was built. in the process of meshing the wall, the software divides the effective wall into 20 parts in length and width and calculations related to sound pressure level on inner wall surface, transmission loss through the wall and leakage from the pores are performed on these meshes. the built software was designed in 5 forms. form 1 for defining hall dimensions and areas of used materials, form 2 and 3 for defining sound sources inside the hall and form 5 for defining and managing materials, were designed. form 4 was used for completing required information and monitoring calculation results and software outputs. the software was run with the input data of a gas power plant and outputs were analyzed. the average relative difference between outputs of software and field measurements was below 5%. hence the built software offers an acceptable estimation of industry’s propagated noise in the environment. this estimation can be used by industry managers for locating and designing the industry and for environmental impact assessment of the industry.