3.6.1 During noise level measurement, only seafarers
                           necessary for the operation of the ship and persons taking the measurements
                           shall be present in the space concerned.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           3.6.2 Sound pressure level readings shall be taken
                           in decibels using an A-weighting (dB(A)) and C-weighting (dB(C)) filter
                           and if necessary also in octave bands between 31.5 and 8,000 Hz.
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           3.6.3 The noise level measurements shall be taken
                           with the integrating sound level meter using spatial averaging (as
                           described in paragraph 3.13.1) and over a time period until stable
                           readings are found or at least 15 s in order to represent the average
                           value from variations due to irregular operation or variations in
                           the sound field. Readings shall be made only to the nearest decibel.
                           If first decimal of the dB reading is 5 or higher, the reading shall
                           be made to nearest higher integer.