noise calculation is the process of calculating the level of noise immission using the metric dB(A). Noise immission is created by noise sources (noise emission) of various types which are propagating noise into the environment. A single source will create a certain level of immission primarily driven by originating sound power level and distance influenced by e.g. absorption and reflection. Several noise sources result in typically higher levels of immission. The method or process of determining the resulting immission level is called noise calculation, its graphical representation is called noise map.
Noise calculation is done for the following reasons
* to calculate a current situation based on existing physics, mostly when a physical measurement at a location is impractical
* to predict the resulting immission levels based on a planned change, e.g. set up of a new machine
Mostly, noise calculation is part of any such planning process and may become part of the decision process for physical change