ANSI S12.18 : 1994

Foreword
0 Introduction
1 Scope, purpose and applications
2 References to other standards
3 Definitions
4 Environmental requirements
  4.1 General
  4.2 Factors influencing sound pressure level measurements
  4.3 Outdoor measurement of sound pressure level
  4.4 METHOD #1: General method for routine measurements
  4.5 METHOD #2: Precision method for accurate measurement
  4.6 Terrain equivalence
  4.7 Ground equivalence
5 Acoustical environment
  5.1 Types of measurements
  5.2 Classification of the sound source
6 Instruments for measuring sound pressure level outdoors
  6.1 Sound level meter/analyser
  6.2 Microphone
  6.3 Calibration
  6.4 Tape recorder
  6.5 Miscellaneous
  6.6 Configuration of measuring system
  6.7 Wind speed and direction
  6.8 Temperature sensor
7 Measurement
  7.1 Premeasurement planning
  7.2 Sound descriptor
  7.3 Source configuration and operation
  7.4 Duration or sample size
  7.5 Data collection
8 Data reduction
  8.1 Corrections
  8.2 Experimental error
9 Reporting
  9.1 Introductory information
  9.2 Site sketches
  9.3 Characterisation of the source
  9.4 Documentation of the instrumentation
  9.5 Meteorological data
  9.6 Acoustical data
  9.7 Other observations
Annex
A - Propagation of sound outdoors
    A.1 Geometrical divergence
    A.2 Atmospheric absorption
    A.3 Effects of the environment
    A.4 Miscellaneous attenuation
    A.5 Discussion

Describes procedures for the measurement of sound pressure levels in the outdoor environment, considering the effects of the ground, the effects of refraction due to wind and temperature gradients, and the effects due to turbulence.