ISO 131:1979

Acoustics — Expression of physical and subjective magnitudes of sound or noise in air

Acoustique — Expression des intensités physique et subjective d'un son ou d'un bruit aérien

General Information

• Status: Withdrawn
• Publication Date: 31-Oct-1979
• Withdrawal Date: 31-Oct-1979
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• Technical Committee: ISO/TC 43 - Acoustics
• Drafting Committee: ISO/TC 43 - Acoustics
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 07-Mar-1996

Relations

• Revises: ISO/R 357:1963 - Withdrawal of ISO/R 357-1963
• Effective Date: 15-Apr-2008

Standards Content (Sample)

International Standard 131
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MEXnYHAPOnHAR OPTAHM3AUMR no CTAHAAPTH3AUMM*ORGANlSATlON INTERNATIONALE DE NORMALISATION
Acoustics - Expression of physical and subjective
‘-
magnitudes of sound or noise in air
Acoustique - Expression des intensités physique et subjective d’un son ou d’un bruit aérien
First edition - 1979-11-01
I UDC 534.323 Ref. No. IS0 131-1979 (El
Lu
Descriptors : acoustics, acoustic measurement, noise (sound), airborne sound, quantities, units of measurement, sound pressure, sound power,
r-
c sound intensity.
7
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s Price based on 3 pages

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Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards institutes (IS0 member bodies). The work of developing Internatio-
nal Standards is carried out through IS0 technical committees. Every member body
interested in a subject for which a technical committee has been set up has the right to
be represented on that committee. International organizations, governmental and non-
governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
IS0 Council.
the
International Standard IS0 131 was developed by Technical Committee ISO/TC 43,
Acoustics.
It was submitted directly to the IS0 Council, in accordance with clause 6.13.1 of the
ISO. It cancels and replaces IS0 Recommendation
Directives for the technical work of
R 131-1959, which had been approved by the member bodies of the following coun-
tries :
Australia India Romania
Austria Italy Spain
Czechoslovakia Japan Sweden
Mexico Switzerland
Denmark
Finland Netherlands United Kingdom
France New Zealand USA
Germany, F. R. Poland USSR
Hungary Portugal
No member body had expressed disapproval of the document
It also cancels and replaces IS0 Recommendation R 357-1963 which had been appro-
ved by the member bodies of the following countries :
Australia Finland Portugal
Austria France
Sweden
Belgium Germany, F. R. Switzerland
Brazil Hungary
United Kingdom
Burma India U SA
Canada Japan
USSR
Chile
Netherlands Yugoslavia
Czechoslovakia New Zealand
Denmark Poland
No member body had expressed disapproval of the document.
O International Organization for Standardization, 1979 O
Printed in Switzerland

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INTERNATIONAL STANDARD IS0 131-1979 (E)
Acoustics - Expression of physical and subjective
magnitudes of sound or noise in air
3.3 Sound power level
1 Scope and field of application
The sound power level, Lw2), expressed in decibels, of a
This International Standard expresses the physical and
source is given by the formula :
subjective magnitudes which are used in the description of
acoustical sound or noise in air.
P
10 lg -
PO
2 References
\
where
IS0 31 17, Quantities and units of acoustics.
P is the total sound power emitted by source of sound or
ISOIR 226, Normal equal-loudness contours for pure tones
noise;
and normal threshold of hearing under free field listening
conditions.
Po is the reference sound power ( = 1 pV4.
IS0 1683, Acoustics - Preferred reference quantities for
NOTE - A-weighting is frequently employed yielding a value of the
acoustic levels. 1)
A-weighted sound power level in decibels. Other weightings may also
be used.
Physical magnitudes of sound or noise
3
3.4 Sound intensity level
3.1 General
The sound intensity level, LI, expressed in decibels, of a sound
or noise is given by the formula :
It is recommended that data on the physical magnitude of
sound or noise be expressed by a statement of the sound
I
10 lg -
pressure level measured at a particular point (see 3.2) or in
IO
terms of the sound power level of a source (see 3.3). Reference
quantities for acoustic levels used in this International Standard
where
are in accordance with those of IS0 1683.
I is the sound intensity of the sound field;
3.2 Sound pressure level
I
...