This Nordtest method states procedures for measuring road traffic noise inside and outside buildings and in open terrain, under specified traffic and environmental conditions, at distances up to 100 m from the road. The accuracy is that of an ISO survey method (grade 3). The method aims at obtaining noise levels as they occur during slightly downward atmospheric refraction.
Measurements carried out according to this Nordtest method yield the total A-weighted energy-equivalent sound pressure level. Nordtest method NT ACOU 039 is an engineering method intended for more general application also enabling the measurement of maximum A-weighted sound pressure levels and sound pressure levels in octave bands. NT ACOU 039 allows measurements at distances in excess of 100 m from the road.
The method specifies how to measure the noise level at a given position in a well-defined way, and how, by measuring road traffic noise simultaneously in several microphone positions, the noise levels in these positions can be efficiently determined.