ISO 4412-2:1991

SLOVENSKI STANDARD
01-december-1998
)OXLGQDWHKQLND3RVWRSHNXJRWDYOMDQMDUDYQL]UDþQHJDKUXSDGHO0RWRUML
Hydraulic fluid power -- Test code for determination of airborne noise levels -- Part 2:
Motors
Transmissions hydrauliques -- Code d'essai pour la détermination du niveau de bruit
aérien -- Partie 2: Moteurs
Ta slovenski standard je istoveten z: ISO 4412-2:1991
ICS:
17.140.20 Emisija hrupa naprav in Noise emitted by machines
opreme and equipment
23.100.10 +LGUDYOLþQHþUSDONHLQPRWRUML Pumps and motors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ISO
INTERNATIONAL
STANDARD
4412-2
Second edition
1991-08-15
Mydraulic fluid power - Test Code for
determination of airborne noise levels -
Part 2:
Motors
Transmissions kydrauliques - Code d’essai pour la determination du
niveau de bruit aerien -
Partie 2: Moteurs
Reference number
ISO 4412-23 991 (E)
Contents
Page
1 Scope . . . . . . . . . . . . . . . . . . . .~.-.-.-.~-.~.-. 1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . .e. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-. 2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-. 2
4 Measurement uncertainty
. . . . . . . . . . . . . . . . . . . . . .-.-.-.-. 2
5 Test environment
6 Instrumentation . . . . . . . . . . . . . ._.-.-.-.”.“. 3
7 Installation conditions . . . . . . . . . . .__._.-. 3
8 Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
9 Location and number of Sound measurement Points .
.............................. ............................................ 4
IO Test procedure
............................................ 4
11 Information to be recorded .
........................ ......................................................... 6
12 Test report
13 Identification Statement (Reference to this part of ISO 4412) 6
Annexes
. . .r.“.-.-. 7
A Calculation of Sound levels
........................................ 8
B Errors and classes of measurement
........... 9
C Guidelines for the application of this patt of ISO 4412
............................. ................................................. 20
D Bibliography
0 ISO 1991
All rights reserved. No part of this publication may be reproduced or utilized in any ferm
or by any means, electronie or mechanical, including photocopying and microfilm, without
Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Prlnted In Switzerland
ii
ISO 4412=2:1991(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, govern-
mental and non-governmental, in Iiaison with ISO, also take part in the
work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an Inter-
national Standard requires approval by at least 75 % of the member
bodies casting a vote.
International Standard ISO 4412-2 was prepared jointly by Technical
Committees lSO/TC 131, Fluid power Systems, Sub-Committee SC 8,
Product testing and contamination control and ISO/TC 43, Acoustics.
This second edition cancels and replaces the first edition (ISO
4412-2:1984), of which clauses 12 and 13 have been transferred to form
a new annex A. The former annex A has become annex B, and annexes
C and D have been added.
ISO 4412 consists of the following Parts, under the general title Hydraulic
fluid power - Test Code for determination of airborne noise Levels:
- Part 1: Pumps
- Part 2: Motors
- Part 3: Pumps - Method using a parallelepiped microphone array
Annexes A and B form an integral part of this part of ISO 4412. Annexes
C and D are for information only.

ISO 441202:1991(E)
Introduction
In hydraulic fluid power Systems, power is transmitted and controlled
through a liquid under pressure in an enclosed circuit. Motors are
components which convert rotary fluid power to mechanical power.
During the process of converting hydraulic fluid power to mechanical
power, airborne noise, fluid-borne vibrations and structure-borne vi-
brations are radiated from the motor.
The airborne noise level of a hydraulic fluid power motor is an important
consideration in component selection. The noise measurement tech-
nique must, therefore, be such as to yield accurate appraisals of these
airborne noise levels. The determination of noise levels is complicated
by the interactions which occur during noise measurements. The fluid-
borne vibrations from the motor tan be transmitted to the circuit and
ultimately give rise to background airborne noise levels which could af-
fett the determination of the motor airborne noise levels.
The procedures described iy1 this part of ISO 4412 are intended to
measure only the airborne noise radiated directly from the motor under
test.
iv
INTERNATIONAL STANDARD
Hydraulic fluid power - Test code for determination of
airborne noise Ievels -
Part 2:
Motors
1 Scope 2 Normative references
The following Standards contain provisions which,
This part of ISO 4412 establishes a test code de- through reference in this text, constitute provisions
scribing procedures, based on ISO 2204, for the de- of this part of ISO 4412. At the time of publication,
termination of the Sound power levels of a hydraulic the editions indicated were valid. All Standards are
subject to revision, and Parties to agreements based
fluid power motor, under controlled conditions of in-
stallation and Operation, suitable for providing a ba- on this patt of ISO 4412 are encouraged to investi-
sis for comparing the noise levels of motors in terms gate the possibility of applying the most recent edi-
of: tions of the Standards indicated below. Members of
IEC and ISO maintain registers of currently valid In-
- A-weighted Sound power level; ternational Standards.
-
octave band Sound power levels. ISO 3448:1975, Industrial liquid lubricants - ISO vis-
cosity classification.
From these Sound power levels, if required, refer-
ence Sound pressure levels may be calculated for ISO 3744:1981, Acousfics - Determination of Sound
repor-ting purposes in accordance with annex A. power levels of noise sources - Engineering meth-
ods for free-field conditions over a reflecting plane.
For general purposes, the frequency range of inter-
est includes the octave bands with centre fre- ISO 3745:1977, Acousfics - Determination of Sound
quencies between 125 Hz and 8000 HZ?) power Levels of noise sources - Precision methods
for anechoic and semi-anechoic rooms.
Due to the inherent difliculties in the measurement
of low-Speed motor Performance, this part of ISO 5598:1985, Fluid power Systems and componenfs
ISO 4412 is limited to motors operating at Speeds - Vocabulary.
exceeding 50 r/min.
ISO 6743-4:1982, Lubricants, industrial oils and re-
Guidelines for the application of this part of ISO 4412 lated products (class L) - Classifkation - Part 4:
are given in annex C. Family H (Hydraulic Systems).
This patt of ISO 4412 is applicable to all types of IEC 50(801):1984, International Electrotechnical Vo-
hydraulic fluid power motors operating under cabulary - Chapter 801: Acoustics and electro-
steady-state conditions, irrespective of size, except acoustics.
for any limitations imposed by the size of the test
environment (see clause 5). IEC 651:1979, Sound level mefers.
1) lHz=ls-'
ISO 441292:1991(E)
NOTE 4 The weighting network or the width of the fre-
3 Definitions
quency band used should always be indicated. The refer-
ence Sound power is 1 pW3).
For the purposes of this part of ISO 4412, the defi-
nitions given in ISO 5598, IEC 50 and the following
3.8 volume of Source under test: Volume of the en-
definitions apply. It is accepted that the latter defi-
velope of the whole motor under test.
nitions may differ from those in other specific Inter-
national Standards.
3,l he Sound field: Sound field in a homogeneous,
4 Measurement uncertainty
isotropic medium free of boundaries.
Methods of measurement should be used which
NOTE 1 In practice, it is a Geld in which the effects of
the boundaries are negligible over the frequency range
tend to result in Standard deviations which are equal
of interest.
to or less than those specified in table 1. Methods
given in ISO 3744 meet this requirement.
3.2 free field over a reflecting plane: Field produced
by a Source in the presence of one reflecting plane
Table 1 - Standard deviation of Sound power level
on which the Source is located.
determinations
3.3 reverberant Sound field: That Portion of the
Standard deviation, dB,
Sound field in a test room over which the influence
for octave bands centred on:
of Sound received directly from the Source is negli-
gible.
125 Hz 250 Hz
500 Hz 1000 Hz to 8000 Hz
4000 Hz
3.4 anechoic room: A test room having boundaries
590 370 270 270
which absorb essentially all of the incident Sound 390
energy over the frequency range of interest, thereby
affording free-field conditions over the measurement
The Standard deviations given in table 1 include the
surface.
effects of allowable variations in the positioning of
the measurement Points and in the selection of any
3.5 mean-Square Sound pressure: The Sound
prescribed measurement surface, but exclude vari-
pressure averaged in space and time on a mean-
ations in the Sound power output of the Source from
Square basis.
test to test.
NOTE 2 In practice, this is estimated by space and time
NOTE 5 The A-weighted Sound power level will in most
averaging over a finite path length or over a number of
practical cases be determined with a Standard deviation
fixed microphone positions.
of approximately 2 dB.
3.6 mean Sound pressure level: Ten times the log-
arithm to the base 10 of the ratio of the mean-Square
Sound pressure to the Square of the reference Sound
5 Test environment
pressure, in decibels (dß).
Tests shall be conducted in an environment which
NOTE 3 The weighting network or the width of the fre-
quency band used should always be indicated; for exam- provides “free-fieId over a reflecting plane” or
ple, A-weighted Sound pressure Level, octave band Sound conditions which meet the
“special reverberant”
pressure level. The reference Sound pressure is 20 ppa*).
environmental qualification requirements described
in ISO 3744:1981, clause 4 and annex A.
3.7 Sound power level: Ten times the logarithm to
For more precise measurements, conduct tests in
the base 10 of the ratio of a given Sound power to
the reference Sound power, in decibels. accordance with ISO 3745.
2) 1 IlPa = 10-6 N/m*
3) 1 pw = 10-12 w
ISO 441292:1991 (E)
7.4.2 The test fluid and degree of filtration shall be
6 Instrumentation
in accordance with the motor manufacturer’s rec-
ommendations.
6.1 The instrumentation used to measure fluid
flow, fluid pressure, motor Speed and fluid tempera-
7.4.3 Inlet and discharge lines shall be installed
ture shall be in accordance with the recommen-
with diameters in accordance with the manufac-
dations for “industrial class” accuracy of testing; i.e.
turers’ recommended practice.
class C given in annex B.
7.4.4 The outlet pressure gauge shall be mounted
6.2 The instrumentation used for acoustical
at the Same height as the outlet fittings or it shall be
measurements shall be in accordance with IEC 651.
calibrated for any height differente.
This instrumentation shall be in accordance with
ISO 3744 for both Performance and calibration; i.e.
7.4.5 Pressure fluctuations and standing waves in
for engineering (grade 2)
type 2 instruments
the inlet and outlet ports shall be minimized by such
measurements.
measures as selected line lengths, long lengths of
flexible hose, accumulators, inline silencers and in-
line pulsation Pumps.
7 Installation conditions
7.4.6 A stable load valve shall be used in the outlet
7.1 Motor location
line if back pressure is regulated.
NOTE 6 Unstable load valves in the lines tan generate
The motor may be located in any Position consistent
and transmit noise through the fluid and piping which tan
with the Source installation and measurement sur-
emerge as airborne Sound at the motor-.
face (or microphone traverse) requirements speci-
fied in ISO 3744 for the test environment being used.
7.4.7 Any control valves shall be positioned far
from the motor, preferably outside the test room, to
7.2 Motor mounting
minimize the interaction.
7.2.1 The motor mounting shall be constructed so
7.4.8 All fluid lines and valves in the test space
that it will minimize the noise radiated by the
shall be wrapped with sound-isolating materials, if
mounting as a result of motor vibrations.
required (see 10.1). Material having a sound-
transmission loss of at least IO dß at 125 Hz, and a
greater loss at higher frequencies, shall be used.
7.2.2 The mounting bracket shall be constructed of
high-damping material or with sound-damping and
sound-insulating material applied to the bracket as
8 Operating conditions
required.
8.1 Determine the Sound p
...