SIST ETS 300 753 E1:2006

SLOVENSKI STANDARD
SIST ETS 300 753 E1:2006
01-februar-2006
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Equipment Engineering (EE); Acoustic noise emitted by telecommunications equipment
Ta slovenski standard je istoveten z: ETS 300 753 Edition 1
ICS:
17.140.20 Emisija hrupa naprav in Noise emitted by machines
opreme and equipment
33.050.01 Telekomunikacijska Telecommunication terminal
terminalska oprema na equipment in general
splošno
SIST ETS 300 753 E1:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 753 E1:2006

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SIST ETS 300 753 E1:2006
EUROPEAN ETS 300 753
TELECOMMUNICATION October 1997
STANDARD
Source: EE Reference: DE/EE-01023
ICS: 33.020
Key words: Acoustic, emission, environment, noise
Equipment Engineering (EE);
Acoustic noise
emitted by telecommunications equipment
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1997. All rights reserved.

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ETS 300 753: October 1997
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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Contents
Foreword .5
Introduction.5
1 Scope .7
2 Normative references.7
3 Definitions and symbols .8
3.1 Definitions .8
3.2 Symbols .9
4 Measurement methodology.9
5 Installation and operation of equipment .9
5.1 Equipment installation.9
5.2 Equipment operation "in-use" .9
5.2.1 Variable emissions - standard temperature test.10
5.2.2 Variable emissions - high temperature test.10
6 Acoustic noise emission limits.10
7 Information to be recorded .12
8 Information to be reported.12
9 Verification of declared A-weighted sound power levels.12
Annex A (normative): Measurement methods for acoustic noise emission from open air outdoor
equipment.13
A.1 Scope .13
A.2 Source directionality .13
A.3 Installation and operation of equipment .13
A.3.1 Daytime simulation.13
A.3.2 Night-time simulation .13
A.4 Information to be recorded .13
A.5 Information to be reported.13
Annex B (normative): Recommended sound power limits for open air outdoor equipment.14
Annex C (informative): Recommended method for the detection and reporting of prominent discrete
tones.16
Annex D (informative): Motivation for this ETS .17
Annex E (informative): The relationship between sound power and sound pressure.18
Annex F (informative): Sound power measurement methods .19
F.1 Reverberation room technique.19
F.1.1 Concept.19

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F.1.2 Measurement procedure. 19
F.2 Free field over a reflecting plane technique. 19
F.2.1 Concept. 19
F.2.2 Measurement procedure. 20
History. 21

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ETS 300 753: October 1997
Foreword
This European Telecommunication Standard (ETS) has been produced by the Equipment Engineering
(EE) Technical Committee of the European Telecommunications Standards Institute (ETSI).
Transposition dates
Date of adoption: 19 September 1997
Date of latest announcement of this ETS (doa): 31 December 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 June 1998
Date of withdrawal of any conflicting National Standard (dow): 30 June 1998
Introduction
Compatibility with the end-use environment is a primary concern for purchasers and manufacturers of
telecommunications equipment. An important compatibility issue is the amount of acoustic noise emitted
by the equipment. This ETS is intended to meet four primary needs of purchasers and manufacturers with
regard to this issue:
- specification of acoustic noise emission measurement methods;
- specification of acoustic noise emission limits;
- specification of a method for reporting acoustic noise emission;
- specification of a method for verification of declared noise emission values.
To develop practical specifications and to have the capacity to make fair comparisons between
equipment, it is essential to have a single, technically established method for the measurement of acoustic
emission. Therefore, this ETS specifies the use of sound power measurement and, more specifically,
adopts ISO 7779 [1] as the primary measurement document.
Sound power levels can be used for direct comparison of noise emission for functionally similar equipment
manufactured by different vendors, and/or in the calculation of estimated sound pressure levels for spaces
where the equipment is to be installed. The use of sound power level, instead of emission sound pressure
level, as the specified quantity for product noise emission has clear precedent within the international
noise control community.
The acceptability of the acoustic emission from a piece of equipment depends upon a number of details
that vary from installation to installation, and the number of possible installations is extensive. Accordingly,
the goal of this ETS is to specify limits that are applicable to the major installation categories.
The fundamental concern prompting the development of this ETS is the potential adverse impact that
excessive equipment noise can have on people. For that reason, the impact of noise upon human
activities has been carefully considered, and the intent has been to ensure that the acoustic noise emitted
is at, or below, generally accepted levels. The perceptual issues considered included task concentration,
speech communication, annoyance and other similar parameters. Generally, the relevant noise exposure
levels are well below those needed to ensure worker safety and health. Requirements related to worker
safety and health (including those related to infrasound and ultrasound) can be found in EEC Directive
86/188/EEC [4].
This ETS specifies that manufacturers report measured A-weighted sound power values for equipment.
Given that it is impractical and unnecessary to measure every manufactured unit, the reported sound
power value should be one that all, or nearly all, units of a particular model will not exceed. This means
that the reported value needs to take into account both production variation and the precision of the
measurement method. ISO 9296 [2] specifies methods that address these issues and is therefore
specified in this ETS as the method for declaring sound power values. ISO 9296 [2] also specifies a
method for verification of declared sound power values.

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For further information regarding the motivation for the development of this standard, see annex D.

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1 Scope
This European Telecommunication Standard (ETS) specifies acoustic noise emission limits for equipment
used in telecommunication locations as specified in the ETS 300 019-1 [3] series. This ETS covers
switching, transmission, power, supervisory, as well as tariff and billing equipment.
This ETS also specifies methods for measuring, reporting and verifying the noise emission of
telecommunications equipment. The details of the methods are found in ISO 7779 [1] and ISO 9296 [2].
The descriptor used to quantify acoustic noise emission is the declared A-weighted sound power level in
units of bels.
The limits contained herein apply only to the airborne acoustic noise generated by equipment during
normal operation. That is, the limits do not apply when operating under emergency conditions or when the
equipment is being serviced. Also, the limits do not apply to equipment features which produce sound as
an intentional aspect of their operation, e.g. alarm signals, attention signals, speech signals and so on.
(For more information on that topic, see ETR 116 [5]). Furthermore, the present document does not
specify maximum sound pressure level limits in specific environments.
Contained within the present document are 6 annexes. Annex A specifies methods for measuring the
acoustic noise emitted from equipment manufactured for open air outdoor locations. Annex B contains
tables of recommended A-weighted sound power limits for open air outdoor equipment. Annex C
discusses the emission of pure tones from equipment. Annex D reviews the motivation for the creation of
this ETS. Annex E discusses the relationship between sound power and sound pressure. Annex F briefly
summarizes the sound power measurement methods used within this ETS.
2 Normative references
This ETS incorporates by dated or undated reference provisions from other publications. These normative
references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this ETS
only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies.
[1] ISO 7779: "Acoustics - Measurement of Airborne Noise Emitted by Computers
and Business Equipment".
[2] ISO 9296: "Acoustics - Declared Noise Emission Values of Computer and
Business Equipment".
[3] ETS 300 019-1 (1994): "Equipment Engineering (EE); Environmental conditions
and environmental tests for telecommunications equipment Part 1: Classification
of environmental conditions" (this ETS has eight sub-parts).
[4] EEC Directive 86/188/EEC: "On the Protection of Workers From the Risks
Related to Exposure of Noise at Work" [OJ L 137 24.05.86 p.28 modified by
L 001 03.01.94 p.484].
[5] ETR 116 (1994): "Human Factors (HF); Human factors guidelines for ISDN
Terminal equipment design".
[6] ECMA TR/27: "Method for prediction of installation noise levels".

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3 Definitions and symbols
3.1 Definitions
For the purposes of this ETS, the following definitions apply.
The following terms have the meanings as defined in ISO 7779 [1] and ISO 9296 [2], which are here
repeated for the sake of convenience:
sound power level (L ): The logarithm (base 10) of the ratio of a given sound power to the reference
W
sound power. The weighting network (A-weighting) or the width of the frequency band used needs to be
indicated. The reference sound power is 1 pW. Units: bels.
declared A-weighted sound power level (L ): A statistical maximum A-weighted sound power level
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for manufactured units, taking into account tolerances of production and measurement variance,
described in ISO 9296 [2]. Units: bels.
NOTE 1: Typically, L is 0,3 bels higher than the A-weighted sound power level measured on
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an average manufactured unit. L is used for all equipment classes and in the
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specification of noise emission limits.
sound pressure level (L ): Ten times the logarithm (base 10) of the ratio of the time-mean-square sound
P
pressure to the square of the reference sound pressure. The weighting network (A-weighting) or the width
of the frequency band used needs to be indicated. The reference sound pressure is 20 μPa. Units:
decibels.
A-weighting filter: Response characteristic of a filter used in acoustic measurement systems which
attenuates low frequency and high frequency acoustic energy. This filter is used to provide a frequency
response characteristic similar to that of the human auditory system.
The following definitions are peculiar to this ETS:
high temperature A-weighted sound power level (HL ): A statistical maximum A-weighted sound
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power level for manufactured units, taking into account tolerances of production and measurement
variance. The method for determining the high temperature A-weighted sound power level is similar to that
used in the determination of declared sound power values, as described in ISO 9296 [2]. HL is used
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for equipment whose operational noise varies with temperature. Units: bels.
high temperature limit: The maximum temperature specified for the stated environmental class of the
equipment under test according to the relevant subpart of ETS 300 019-1 [3].
telecommunication equipment room: An area dedicated to large telecommunication systems.
Unattended rooms are typically occupied only for service and maintenance activities. These activities may
last for periods of time greater than one hour.
business area: An area where the principal activity is office / clerical work or similar activities. These
areas typically contain multiple single-person work areas. Sound levels should be low enough to provide
good conditions for task concentration and speech communication.
office: An area where individuals are primarily engaged in individual or small group intellectual tasks
which require excellent conditions for task concentration and speech communication. A typical example
would be a single-person closed office.
power room: Defined as an area designed to house heavy equipment including, but not limited to, power
generation equipment, heating equipment, and ventilation equipment. Typically occupied only for short
periods during servicing.
underground vault: Defined as a sealed underground enclosure which is large enough to be entered for
servicing equipment contained therein. Typically occupied only for service and maintenance activities.
These activities may last for periods of time greater than one hour.
protected area: Location intended to be used for rest, recuperation and contemplation.

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NOTE 2: There is no IEC description for this class but there is a requirement of some European
countries for this special category. These areas could be adjacent to hospitals,
churches, libraries, etc.
rural: Relating to areas, typically, in the countryside with low population density.
urban: Relating to areas, typically, in towns and cities with high population density.
industrial: Relating to areas, typically, of transient population and heavy manufacturing activity.
daytime: The part of the day considered to extend over normal waking hours. Typically, the period during
which people are most likely to be engaged in activities related to business, education, active recreation,
etc.
night-time: The part of the day considered to be normal sleeping hours. This period includes evening and
early morning hours when people are likely to be awake but not yet fully involved in typical daytime
activities.
3.2 Symbols
For the purposes of this ETS, the following symbols apply:
L sound power level
W
L declared A-weighted sound power level
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L sound pressure level
p
HL high temperature declared A-weighted sound power level
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4 Measurement methodology
The measurement methods specified in ISO 7779 [1] shall be used for determining the sound power of
products. Annex A contains additional methods and measurements relating to open air outdoor
equipment.
5 Installation and operation of equipment
The installation and operation conditions specified in ISO 7779 [1] shall be used for determining the sound
power of products. Where there are differences between this ETS and ISO 7779 [1], the requirements
contained herein shall be followed.
The equipment shall be configured and operated according to its normal intended use. Within that
constraint and the constraints specified below, the equipment shall be configured and operated to ensure
worst case acoustic noise emission.
5.1 Equipment installation
The specific installation will depend upon the sound power measurement technique being used
(reverberation room or free-field over a reflecting plane), and upon the normal installation requirements of
the equipment being measured.
5.2 Equipment operation "in-use"
For telecommunication equipment whose operational noise varies with functional load, the electrical input
and load conditions of the equipment shall be chosen to obtain full functional utilization of the equipment
under test. Dissipation shall be maximized by selection of supply power and load conditions.
Only the sound power of continuous, steady-state noise sources shall be measured. Therefore, the
equipment is to be operated such that intermittent sources are not active. Such sources include (but are
not restricted to) alarms, attention signals, printing mechanisms, disk-drive seeking mechanisms and so
on.

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For telecommunication equipment whose operational noise varies with temperature (e.g. equipment using
variable speed air moving devices), the sound power will be measured with the equipment operating
under the two conditions specified in subclauses 5.2.1 and 5.2.2.
5.2.1 Variable emissions - standard temperature test
For the first test, the ambient temperature in the test environment shall be 23°C ± 2°C, in accordance with
ISO 7779 [1]. Data obtained from testing as specified in this clause is to be used in the determination of
the declared A-weighted sound power level (L ) for the equipment.
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5.2.2 Variable emissions - high temperature test
For the second test, the sound power shall be measured with the equipment operating as it would in an
ambient temperature equal to the high temperature limit (see next paragraph). Data obtained from testing
as specified in this clause is to be used in the determination of the high temperature A-weighted sound
power level (HL ) for the equipment.
WAd
This requirement can be satisfied using one of two methods. In the first method, the ambient temperature
in the test environment shall be the high temperature limit. In the second method, the ambient
temperature in the test environment shall be 23°C ± 2°C but, the rotational speed of air moving devices
within the equipment under test shall be set to the speed that the devices would run at when the
equipment is operating in an ambient temperature equal to the high temperature limit.
6 Acoustic noise emission limits
Maximum acoustic noise emission levels for telecommunication equipment are specified in tables 1 to 4.
Entries are organized according to the Environmental Classes specified in ETS 300 019-1 [3] and to the
environmental descriptions found in subclause 3.1 of the present ETS. In accordance with ISO 9296 [2],
these maximum product emission levels are declared A-weighted sound power levels, L , in units of
WAd
bels. As specified in clause 8, manufacturers are to provide declared A-weighted sound power levels for
their products. Consequently, the data provided by manufacturers can be compared directly to the values
in tables 1 to 4. In order to avoid possible conflict with noise exposure regulations that exist within some
European countries, open air outdoor equipment noise emission is not addressed here but is discussed in
separate annexes (annexes A and B).
The limits apply only to L values, and are not applicable to HL values. Furthermore, the limits
WAd WAd
apply to the "in-use" operational conditions specified in subclause 5.2.
Note that some environmental descriptions have sub-categories based upon typical equipment placement.
Equipment intended to be located in close proximity to desk work locations has lower acceptable limits
than equipment intended to be located far from desk work locations.
These limits apply to a functional unit as defined in clause 4 of ISO 7779 [1]. If a functional unit consists of
multiple frames, these limits apply to a single frame as described in subclause 5.5 of ISO 7779 [1].

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Table 1: Limits for stationary equipment used in weather protected locations
Environmental class
Environmental L 3.1 3.2 3.3
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description units
Telecommunication equipment room bels 7,5 7,5 7,5
(unattended)
Telecommunication equipment room bels 7,2 7,2 7,2
(attended)
Business area bels 6,8 nr nr
(>4 m from desk work locations)
Business area bels 6,3 nr nr
(<4 m from desk work locations)
Office bels 5,5 nr nr
(floor-standing equipment)
Office bels 5,0 nr nr
(desktop equipment)
Power room bels 8,3 8,3 8,3
Table 2: Limits for ship environment equipment
Environmental class
Environmental L 6.1
WAd
description units
Telecommunication equipment room bels 7,5
(unattended)
Telecommunication equipment room bels 7,2
(attended)
Business area bels 6,8
(>4 m from desk work locations)
Business area bels 6,3
(<4 m from desk work locations)
Office bels 5,5
(floor-standing equipment)
Office bels 5,0
(desktop equipment)
Power room bels 8,3
Table 3: Limits for portable and non-stationary use equipment
Environmental class
Environmental L 7.1 7.2
WAd
description units
Telecommunication equipment room bels 7,5 7,5
(unattended)
Telecommunication equipment room bels 7,2 7,2
(attended)
Business area bels 6,8 nr
(>4 m from desk work locations)
Business area bels 6,3 nr
(<4 m from desk work locations)
Office bels 5,5 nr
(floor-standing equipment)
Office bels 5,0 nr
(desktop equipment)

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Table 4: Limits for stationary equipment used in underground locations
Environmental class
Environmental L 8.1
WAd
description
units
Underground vaults bels 7,5
NOTE 1: "nr" indicates that these table entries are not relevant to telecommunication equipment.
NOTE 2: Environmental Classes 3.4, 3.5, 4.1, 4.1E, 6.2, 6.3 and 7.3 are discussed in annex B.
Environmental Classes 5.1 and 5.2 are not covered in this ETS.
7 Information to be recorded
1) The information to be recorded shall be as specified in ISO 7779 [1], including bystander and/or
operator sound pressure levels.
2) For telecommunication equipment whose operational noise varies with temperature, the high
temperature A-weighted sound power level shall be recorded in bels, to the nearest 0,1 bels.
Similarly, the high temperature limit (in °C) and the test method used per subclause 5.2.2 shall be
recorded.
8 Information to be reported
The following information shall be given in implementation conformance statements:
1) a statement specifying which Environmental Classes (see ETS 300 019-1 [3]) and environmental
descriptions (as found in subclause 3.1) are relevant to the equipment;
2) a statement that sound power levels have been obtained in full conformance with the procedures of
this ETS;
3) the declared A-weighted sound power level of the product, L . The value L shall be
WAd WAd
determined according to the method specified in ISO 9296 [2] and using data obtained as specified
in subclause 5.2.1;
4) for equipment whose operational noise varies with temperature, the high temperature A-weighted
sound power level, HL . The value HL shall be determined according to the method
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specified in ISO 9296 [2] and using data obtained as specified in subclause 5.2.2.
NOTE: As described in ISO 9296 [2], A-weighted sound power measurements are to be made
on a number of manufactured units and this data used to obtain a declared sound
power level or a high temperature sound power level for the production series or a
portion thereof. This ETS does not require that the sound power of every
manufactured unit be measured.
9 Verification of declared A-weighted sound power levels
This clause specifies a verification method for declared A-weighted sound power values, L .
WAd
The verification method specified in ISO 9296 [2] shall be used when verification of compliance with this
ETS is required. When conducting sound power measurements, the equipment shall be operated as
specified in this ETS.

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Annex A (normative): Measurement methods for acoustic noise emission
from open air outdoor equipment
This annex specifies additional methods for the measurement of noise emitted by equipment designed for
open air outdoor locations. This information has been provided in a separate annex since the associated
limits (annex B) are currently only recommended values. It is anticipated that this annex will be
incorporated into the main body of this ETS at a future date.
A.1 Scope
In accordance with the main body of this ETS, this annex requires that the declared A-weighted sound
power level, L , of relevant products be measured and recorded. Additionally, this annex specifies that
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additional sound pressure measurements be performed for the purpose of providing an indication of
source directionality. All relevant clauses of the main body of the ETS shall be adhered to in conducting
the measurements, and in the recording and reporting of data. Where there are differences between this
annex and the main body of the ETS, the requirements contained herein shall be followed.
A.2 Source directionality
In addition to the measurement of sound power, an indication of the source directionality shall be obtained
by using only the bystander position measurement method specified in clause 7 of ISO 7779 [1]. That
clause shall be adhered to in conducting the measurements, and in the recording and reporting of
...