ANSI S12.31 : 0

INTRODUCTION
1 GENERAL
    1.1 Scope and Purpose
    1.2 Applicability
    1.3 Measurement Uncertainty
2 DEFINITIONS AND SYMBOLS
    2.1 Definitions
    2.2 Symbols and Recommended Units
3 TEST ROOM REQUIREMENTS
    3.1 General
    3.2 Room volume
    3.3 Room Absorption
    3.4 Temperature and Humidity
4 INSTRUMENTATION
    4.1 General
    4.2 Time Averaging
    4.3 The Microphone and Its Associated Cable
    4.4 Frequency Response of the Instrumentation
          System
    4.5 Filter Characteristics
    4.6 Calibration
5 INSTALLATION AND OPERATION OF NOISE SOURCE
    5.1 General
    5.2 Source Location
    5.3 Source Mounting
    5.4 Auxiliary Equipment
    5.5 Operation of Source During Tests
6 DETERMINATION OF AVERAGE SOUND PRESSURE LEVELS
    6.1 General
    6.2 Microphone Positions
    6.3 Required Data and Conditions of Measurement
7 CALCULATION OF SOUND POWER LEVEL
    7.1 General
    7.2 Direct Method
    7.3 Comparison Method
8 TEST ROOM QUALIFICATION PROCEDURE FOR THE MEASUREMENT
    OF BROAD-BAND SOUND
    8.1 Introduction
    8.2 Instrumentation and Equipment
    8.3 Test Procedures
    8.4 Computation Procedures
    8.5 Qualification
9 CHARACTERISTICS AND CALIBRATION OF REFERENCE SOUND
    SOURCE
    9.1 Characteristics of Reference Sound Source
    9.2 Calibration of Reference Sound Source
10 INFORMATION TO BE RECORDED
    10.1 Noise Source under Test
    10.2 Acoustical Environment
    10.3 Instrumentation
    10.4 Acoustical Data
11 INFORMATION TO BE REPORTED
12 REFERENCES
    12.1 General References
    12.2 Text References
    12.3 Bibliography
APPENDIX A. GUIDELINES FOR THE DESIGN OF REVERBERATION
ROOMS
    A.1 General
    A.2 Volume of Test Room
    A,3 Shape of Test Room and Diffusing Elements
    A.4 Absorption of Test Room Surfaces
APPENDIX B. GUIDELINES FOR THE DESIGN OF ROTATING
DIFFUSERS
APPENDIX C. COMPUTATIONAL PROCEDURES FOR CALCULATING
A-WEIGHTED SOUND POWER LEVEL FROM OCTAVE OR ONE-THIRD
OCTAVE-BAND POWER LEVELS
TABLES:
TABLE 1 Estimated standard deviation of sound power
          level determinations for broad-band sources
          in reverberation rooms
TABLEII Relative tolerances for the instrumentation
          system
TABLE III Corrections for background noise level
TABLE IV Maximum allowable sample standard deviation, s
TABLE V Minimum amount by which narrow-band sound
          pressure level must be below the
          corresponding octave-band sound pressure level
TABLE VI Calibration accuracy for reference sound
          source
TABLE A1 Preferred minimum room volume as a function of
          the center frequency for the lowest frequency
          band of interest
TABLE A2 Recommended room dimension ratios for
          rectilinear rooms

Specifies a Direct and Comparison Method for determining the sound power level produced by a source. Defines test room requirements, source location and operating conditions, instrumentation, and techniques for obtaining an estimate of average sound pressure level from which the sound power level of the source in octave or one-third octave bands is calculated.