(1) A sound level meter which meets Type 1 or Type 2 specifications shall be used.

(2) A microphone windscreen that does not affect the overall reading by more than ±0.5 dB shall be used.

(3) A sound level calibrator shall be used to calibrate the sound level meter. Proper acoustical calibration shall comprise the complete measurement system including extension cables, etc. Field calibration shall be performed immediately before and after each test sequence.