TM 5-805-4/AFJMAN 32-1090
Table C-30. Octave-Band Corrections (in dB) to be Used in Equation C-17 for Obtaining PWL of Transformers in
Different Installation Conditions.
Note 1.
Use C1 for outdoor location or for indoor location in a large
mechanical equipment room (over about 5000 ft.3) containing many
other pieces of mechanical equipment that serve as obstacles to
diffuse sound and breakup standing waveS.
Note 2.
(under about 5000 ft.3) with parallel walls and relatively few other
large-size obstacles that can diffuse sound and breakup standing
waves.
Note
3.
Use C3 for any location where a serious noise problem would result
if the transformer should become noisy above its NEMA rating,
following its installation and initial period of use.
C-27
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