ASA S12.18 1994 R2019
$68.25
ANSI/ASA S12.18-1994 (R2019) American National Standard Procedures for Outdoor Measurement of Sound Pressure Level
| Published By | Publication Date | Number of Pages |
| ASA | 1994 | 30 |
None
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 9 | O Introduction 4 Environmental requirements ………………………………… . 4 4.2 |
| 10 | 1 Scope, purpose, and applications 2 References to other standards 4 |
| 11 | 3 Definitions |
| 12 | General ………………………………………………. . Factors influencing sound pressure level measurements ………… . Geometrical divergence …………………………………. . 3 3 4 4 4.2.2 Atmospheric absorption 4.2.3 Effects of the environment 4.2.4 Miscellaneous attenuation |
| 13 | 4.3 Outdoor measurement of sound pressure level 4.3.1 Geometrical divergence 4.3.2 Atmospheric absorption |
| 14 | 4.3.3 Environmental measurements 4.4 METHOD #1 : General method for routine measurements 4.4.1 Effects of the environment 4.4.1.1 Wind, temperature and cloud cover |
| 15 | 4.4.1.2 Ground, precipitation and snow 4.4.2 Miscellaneous attenuation 4.5 METHOD #2: Precision method for accurate measurement 4.5.1 Effects of the environment 4.5.1.1 Requirements 4.5.1.2 Ground categorization 4.5.1.3 Ground classification |
| 16 | 4.5.1.4 Comparison of sound pressure levels Page 4.5.2 Miscellaneous attenuation 4.6 Terrain equivalence 4.7 Ground equivalence |
| 17 | 5 Acoustical environment 5.1 Types of measurements 5.1.1 Ambient sound measurements 5.1.2 Source measurements 5.2 Classification of the sound source 5.2.1 Temporal characteristics 5.2.2 Frequency characteristics |
| 19 | 6 Instruments for measuring sound pressure level outdoors . . . . . . . . . . . . . . 1 O 6.1 Sound level meter/analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O 6.2 Microphone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O 6.3 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O 6.4 Tape recorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 o 6.5 Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O 6.6 Configuration of measuring system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O 6.7 Wind speed and direction . . . . . .. . . . . . .. .. . . . . . .. .. . . .. . . . . .. . .. .. . 1 O 6.8 Temperature sensor 7 Measurement 7.1 Premeasurement planning 7.2 Sound descriptor 7 .3 Source configuration and operation 7 .3.1 Environmental conditions 7.3.2 Configuration and installation of a source at a sound measurement site 7.3.2.1 Configuration and installation of the source 7.3.2.2 Configuration and installation of auxiliary equipment |
| 20 | 7.3.2.3 Physical environment in which the source is located 7.3.2.4 Specifying the installation of the microphones ii Page 7 .4 Duration or sample size 7 .5 Data collection 7 .5.1 Preliminary verification 7 .5.2 Calibration |
| 21 | 7 .5.3 Meterological 7 .5.4 Background sound 7 .5.5 Sound pressure level at each microphone 7 .5.6 Repeat 7 .5. 7 Final calibration 8 Data reduction 8.1 Corrections 8.1.1 Calibration 8.1.2 Contamination by background sound |
| 22 | 8.1.3 Normalization to reference atmospheric or environmental conditions 8.1.3.1 Temperature/relative humidity 8.1.3.2 General meteorological conditions 8.1.3.3 Ground terrain 8.1.3.4 Miscellaneous effects 8.2 Experimental error |
| 23 | 9 Reporting 9.1 Introductory information 9.2 Site sketches 9.2.1 Plan view 9.2.2 Elevation view 9.3 Characterization of the source 9.4 Documentation of the instrumentation 9.5 Meteorological data 9.6 Acoustical data 9. 7 Other observations |
| 24 | iii Page Annex A Propagation of sound outdoors A.1 Geometrical divergence A.2 Atmospheric absorption A.3 Effects of the environment A.3.1 Effect of a level reflecting ground |
| 25 | A.3.2 Classification of ground surfaces A.3.3 Refraction due to wind velocity and temperature gradients A.3.4 Atmospheric turbulence |
| 26 | A.4 Miscellaneous attenuation A.4.1 Attenuation due to reflections A.4.2 Attenuation due to foliage A.4.3 Attenuation due to barriers A.5 Discussion |
