SIST-TS ISO/TS 7849-1:2014

TECHNICAL ISO/TS
SPECIFICATION 7849-1
First edition
2009-03-15
Acoustics — Determination of airborne
sound power levels emitted by machinery
using vibration measurement —
Part 1:
Survey method using a fixed radiation
factor
Acoustique — Détermination des niveaux de puissance acoustique
aériens émis par les machines par mesurage des vibrations —
Partie 1: Méthode de contrôle employant un facteur de rayonnement
fixe
Reference number
©
ISO 2009
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ii © ISO 2009 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Principle. 4
5 Measuring instrumentation. 5
5.1 General. 5
5.2 Vibration transducer. 5
5.3 Non-contacting transducers. 5
5.4 Amplifier . 6
5.5 Integrator . 6
5.6 Calibration . 6
6 Installation and operation of source under test . 6
6.1 General. 6
6.2 Description of the machine. 7
6.3 Installation . 7
6.4 Operating conditions. 7
7 Determination of the vibratory velocity on the vibrating measurement surface . 7
7.1 General. 7
7.2 Vibrating measurement surface . 7
7.3 Number of measurement positions . 8
7.4 Environmental conditions. 8
7.5 Measurement procedure . 9
7.6 Mounting of the vibration transducer. 9
8 Calculations. 9
8.1 Correction for extraneous vibratory velocity. 9
8.2 Determination of the mean A-weighted vibratory velocity level on the vibrating
measurement surface. 10
8.3 Calculation of the upper limit of the A-weighted airborne sound power level caused by
radiation of structure vibration generated sound . 11
9 Measurement uncertainty . 11
10 Information to be recorded . 13
10.1 Machine under test . 13
10.2 Measurement conditions . 13
10.3 Measuring instrumentation. 13
10.4 Acoustical data . 13
Annex A (informative) Use of the vibration transducer. 14
Annex B (informative) Guidance on the development of information on measurement uncertainty. 16
Bibliography . 19

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
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In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of document:
⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
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⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
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International Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TS 7849-1 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This first edition of ISO/TS 7849-1, together with ISO/TS 7849-2, cancel and replace the first edition of
ISO/TR 7849:1987, which has been technically revised.
ISO/TS 7849 consists of the following parts, under the general title Acoustics — Determination of airborne
sound power levels emitted by machinery using vibration measurement:
⎯ Part 1: Survey method using a fixed radiation factor
⎯ Part 2: Engineering method including determination of the adequate radiation factor
The following part is under preparation:
⎯ Part 3: Amplitude and phase measurements
iv © ISO 2009 – All rights reserved

Introduction
This part of ISO/TS 7849 gives a procedure for the determination of the sound power of the airborne noise
caused by machinery vibration.
The determination of airborne noise emission of a machine by measuring vibration of the machine's outer
surface may be of interest when:
⎯ undesired background noise (e.g. noise from other machines or sound reflected by room boundaries) is
high compared with the noise radiated directly by the machine under test;
⎯ noise radiated by structure vibration is to be separated from noise of aerodynamic origin;
⎯ noise radiated by structure vibration is high compared to the aerodynamic component so that the total
noise radiation is predominantly affected by the structure vibration;
[12]
⎯ sound intensity measurement techniques [ISO 9614 (all parts) ] cannot easily be applied;
⎯ structure vibration generated noise from only a part of a machine, or from a component of a machine set,
is to be determined in the presence of noise from the other parts of the whole machine.
ISO/TS 7849 (all parts) describes methods for the determination of the airborne noise emission of a machine
caused by vibration of its outer surface, expressed by the associated A-weighted airborne sound power being
related to normalized meteorological conditions. This airborne sound power is determined under the
assumption that this quantity is proportional to the mean square value of the normal component of the velocity
averaged over the area of the vibrating outer surface of the machine, and is directly proportional to the area of
the vibrating surface.
The calculation of the airborne sound power needs data of the radiation factor in principle. For this part of
ISO/TS 7849 a radiation factor of 1 is assumed allowing the determination of an upper limit for the radiated
A-weighted sound power level. For typical machines this upper limit may exceed the true A-weighted sound
[12]
power level determined by the intensity procedure of ISO 9614 (all parts) by up to 10 dB. The A-weighted
sound power level determined according to this part of ISO/TS 7849 can be used for sound power level
comparison of relevant vibrating machinery noise of the same family with similar design.

TECHNICAL SPECIFICATION ISO/TS 7849-1:2009(E)

Acoustics — Determination of airborne sound power levels
emitted by machinery using vibration measurement —
Part 1:
Survey method using a fixed radiation factor
1 Scope
This part of ISO/TS 7849 gives basic requirements for reproducible methods for the determination of an upper
limit for the A-weighted sound power level of the noise emitted by machinery or equipment by using surface
vibration measurements. The method is only applicable to noise which is emitted by vibrating surfaces of solid
structures and not to noise generated aerodynamically.
This vibration measurement method is especially applicable in cases where accurate direct airborne noise
[7] [8] [12]
measurements, e.g. as specified in ISO 3746 , ISO 3747 , and ISO 9614 (all parts) , are not possible
because of high background noise or other parasitic environmental interferences; or if a distinction is required
between the total radiated sound power and its structure vibration generated component.
NOTE 1 One of the applications of this part of ISO/TS 7849 is the distinction between the radiation of airborne sound
power generated by structure vibration and the aerodynamic sound power components. Such a distinction is not feasible
[7] [12]
with ISO 3746 and ISO 9614 (all parts) .
NOTE 2 Problems can occur if the noise is generated by small parts of machinery surfaces (sliding contacts, e.g. slip
ring brush or the commutator and
...