ANSI S12.55 : 2012

1 Scope
2 Normative references
3 Terms and definitions
4 Reference meteorological conditions
5 Test rooms
6 Instrumentation
7 Definition, location, installation and operation
   of noise source under test
8 Measurement surface
9 Determination of sound power levels and sound
   energy levels
10 Measurement uncertainty
11 Information to be recorded
12 Test report
Annex A (normative) - General procedures for
        qualification of anechoic and hemi-anechoic
        rooms
Annex B (normative) - Qualification procedure for
        spaces within test rooms used in the
        determination sound power levels and
        sound energy levels of specific noise
        sources
Annex C (normative) - Calculation of A-weighted
        sound power levels and A-weighted sound
        energy levels from one-third-octave band
        levels
Annex D (normative) - Array of microphone positions
        on a spherical measurement surface in
        a free field
Annex E (normative) - Arrays of microphone positions
        on a hemispherical measurement surface in
        hemi-free field
Annex F (normative) - Coaxial circular paths of
        microphones on a hemispherical measurement
        surface a hemi-free field
Annex G (normative) - Meridional paths of microphones
        on a hemispherical measurement surface
        in hemi-free field
Annex H (normative) - Spiral paths of microphones on
        a hemispherical measurement surface
        in a hemi-free field
Annex I (informative) - Guidance on the development
        of information on measurement uncertainty
Bibliography

Defines methods for measuring the sound pressure levels on a measurement surface enveloping a noise source (machinery or equipment) in an anechoic room or a hemi-anechoic room.