Microphone position relative to building façades for in situ measurements

European Noise Directive specifies that strategic noise maps should only take into account incident sound on building façades for the estimation of the environmental noise dose received by residents. This means that reflected sound should not be considered. However, this fact is not possible in "in situ" measurements for noise mapping validation. It is therefore important to take into account the position of the microphone with respect to the facade of the building under study in order to consider effects associated with reflections. These aspects are included in the ISO 1996-2 standard. This work show an experimental study developed in an urban environment where road traffic noise is the main sound source. For this purpose, long-term measurements were carried out simultaneously with three microphones located in three positions described in the ISO 1996-2 standard with respect to building façades: free field, mounted on façade and at a distance from the façade between 0.5 and 2 m. Results are analysed and compared with corrections indicated by the standard.