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Preface
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1.Introduction
2.Planning foundations
2.1General legal foundations
2.1.1Pollution control rights
2.1.2Building law
2.1.3Civil Code, Criminal Code and Administrative Offences Act
2.2The physical terms "sound" and "noise"
2.3Noise, sound emission and sound immission
2.4Acoustic principles
2.4.1The sound scale
2.4.2Calculation rules
2.4.3Definitions of further terms
2.4.4Noise measurements
2.4.4.1The relevance of noise measurements
2.4.4.2The realization of measurements
2.4.4.3The measurement devices
2.5The effect of noise protection constructions
2.6Summary of noise assessment values based on immission values
3.Traffic noise
4.Industrial noise
5.Noise from sports and leisure facilities
6.Noise abatement plans / Noise action plans
7.Planning indications
8.Bibliography
9.Thematic Websites
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PLANNING FOUNDATIONS
   
 2.4.4.2 The realization of measurements

As climatic conditions can influence noise measurements, these influences have to be taken into account during the planning of measurements. In order to prevent background noise from wind for example, the microphone must be equipped with a windbreak out of porous foam (fig. 2/12). Other influences are different wind directions and wind forces, certain kinds of thermal stratification (inversions) as well as snow and frozen ground, which may have a huge impact on the measurement results (the rolling noise from cars is changed by rain for example).

The priority as for noise measurements lies in the compliance with the relevant regulations. The following aspects play a particular role:

Parameters:

Are determined by the frequency and time weighting at the measurement device (e.g. A and F).

 

Measurement device:

Determines the accuracy of the measurement (requirement of the norm), calibration capability.

 

Measurement location:

Determination of the microphone placement depending on the task and environmental conditions.

 

Measurement period:

Is determined by the task and noise situation. The measurement period must be long enough to deliver representative results. What has to be prevented is the impact of extraneous sounds on the measurement results. Sound immission measurements are to be repeated until an unambiguous result is reached, i.e. that the confidence range (see VDI 3723, Page 1 "Application of statistical methods for the description of fluctuating ambient noise levels") of the rating level should lie completely above or below the reference value (e.g. immission guide value).

 

Noise status:

The noise source must possess the adequate operating status.

 

Analysis method:

Delivers the final assessment on the basis of single measurements, e.g. after the consideration of additions (measuring time, noises with discrete components etc.).

 

  
 
 
Fig. 2/12: Windshields at microphones