Testing the acoustical corrections for reflections on a façade

The assessment of noise levels, in the proximity of a building or on its façade, is a requirement of the European Environmental Noise Directive 2002/49/EC concerning environmental noise produced by road and railway traffic, airports and industries. The corrected values for the noise levels and the problems of measuring noise near a façade are discussed here for the case of road traffic. A complete set of measurements in different situations was performed along several roads in an urban environment as well as in a controlled situation using a loudspeaker. The experimental results are then compared against theoretical models and international standards, in particular those that suggest to use a +3 or +6 dB correction as a function of the microphone position and the NordTest method. Some suggestions are given for the different corrective factors to apply when measuring environmental noise between 0 and 2 m away from a building façade, and practical solutions identified.