SIST EN 300 753 V1.3.1:2012

European Standard
Environmental Engineering (EE);
Acoustic noise emitted by telecommunications equipment

2 ETSI EN 300 753 V1.3.1 (2012-01)

Reference
REN/EE-00025
Keywords
acoustic, emission, environment, noise
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
Individual copies of the present document can be downloaded from:
http://www.etsi.org
The present document may be made available in more than one electronic version or in print. In any case of existing or
perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF).
In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive
within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
http://portal.etsi.org/tb/status/status.asp
If you find errors in the present document, please send your comment to one of the following services:
http://portal.etsi.org/chaircor/ETSI_support.asp
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 2012.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3 ETSI EN 300 753 V1.3.1 (2012-01)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and symbols . 8
3.1 Definitions . 8
3.2 Symbols . 10
4 Measurement methodology . 10
5 Installation and operation of equipment . 10
5.1 Equipment installation . 10
5.2 Equipment operation "in-use" . 10
5.2.1 Variable emissions - standard temperature test . 10
5.2.2 Variable emissions - high temperature test . 11
6 Acoustic noise emission limits . 11
7 Information to be recorded . 12
8 Information to be reported . 13
9 Verification of declared A-weighted sound power levels . 13
Annex A (normative): Measurement methods for acoustic noise emission from open air
outdoor equipment . 14
A.1 Scope . 14
A.2 Source directionality. 14
A.3 Installation and operation of equipment . 14
A.3.1 Daytime simulation . 14
A.3.2 Night-time simulation . 14
A.4 Information to be recorded . 15
A.5 Information to be reported . 15
Annex B (informative): Recommended sound power limits for open air outdoor equipment . 16
Annex C (informative): Recommended method for the detection and reporting of prominent
discrete tones . 18
Annex D (informative): Motivation for the present document . 19
Annex E (informative): The relationship between sound power and sound pressure . 20
Annex F (informative): Sound power measurement methods . 21
F.1 Free field over a reflecting plane technique . 21
F.1.1 Concept . 21
F.1.2 Measurement procedure . 21
F.2 Reverberation room technique . 21
F.2.1 Concept . 21
ETSI
4 ETSI EN 300 753 V1.3.1 (2012-01)
F.2.2 Measurement procedure . 21
F.3 Anechoic and semi-anechoic rooms . 22
F.3.1 Concept . 22
F.3.2 Measurement procedure . 22
History . 23

ETSI
5 ETSI EN 300 753 V1.3.1 (2012-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This European Standard (EN) has been produced by ETSI Technical Committee Environmental Engineering (EE).

National transposition dates
Date of adoption of this EN: 16 January 2012
Date of latest announcement of this EN (doa): 30 April 2012
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 October 2012
Date of withdrawal of any conflicting National Standard (dow): 31 October 2012

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. The present document 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, the present
document 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 the present
document is to specify limits that are applicable to the major installation categories.
ETSI
6 ETSI EN 300 753 V1.3.1 (2012-01)
The fundamental concern prompting the development of the present document 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 EC Directive 2003/10/EC [4].
The present document 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 the present document as the method for declaring sound power
values. ISO 9296 [2] also specifies a method for verification of declared sound power values.
For further information regarding the motivation for the development of the present document, see annex D.
ETSI
7 ETSI EN 300 753 V1.3.1 (2012-01)
1 Scope
The present document specifies acoustic noise emission limits for equipment used in telecommunication locations as
specified in the EN 300 019-1 [3] series. The present document covers switching, transmission, power, supervisory, as
well as tariff and billing equipment.
The present document 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], ISO 9296 [2] and in the basic
standards ISO 3741:2010 [7], ISO 3744:2010 [8] and ISO 3745 [9]. 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 [i.1]).
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 the present document. Annex E discusses the
relationship between sound power and sound pressure. Annex F briefly summarizes the sound power measurement
methods used within the present document.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] ISO 7779: "Acoustics -- Measurement of airborne noise emitted by information technology and
telecommunications equipment".
[2] ISO 9296: "Acoustics -- Declared noise emission values of computer and business equipment".
[3] ETSI EN 300 019-1: "Environmental Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment; Part 1: Classification of environmental
conditions".
[4] Directive 2003/10/EC of the European Parliament and of the Council of 6 February 2003 on the
minimum health and safety requirements regarding the exposure of workers to the risks arising
from physical agents (noise).
NOTE: OJ L 42, 15.02.2003 p.38-44.
[5] Void.
[6] ECMA TR/27: "Method for the Prediction of Installation Noise Levels".
ETSI
8 ETSI EN 300 753 V1.3.1 (2012-01)
[7] ISO 3741:2010: "Acoustics -- Determination of sound power levels and sound energy levels of
noise sources using sound pressure -- Precision methods for reverberation test rooms".
[8] ISO 3744:2010: "Acoustics -- Determination of sound power levels and sound energy levels of
noise sources using sound pressure -- Engineering methods for an essentially free field over a
reflecting plane".
[9] ISO 3745:2003: "Acoustics -- Determination of sound power levels of noise sources using sound
pressure -- Precision methods for anechoic and hemi-anechoic rooms".
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI ETR 116 (1994): "Human Factors (HF); Human factors guidelines for ISDN Terminal
equipment design".
3 Definitions and symbols
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
A-weighting filter: response characteristic of a filter used in acoustic measurement systems which attenuates low
frequency and high frequency acoustic energy
NOTE: This filter is used to provide a frequency response characteristic similar to that of the human auditory
system.
business area: area where the principal activity is office / clerical work or similar activities
NOTE: 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.
daytime: part of the day considered to extend over normal waking hours
NOTE: Typically, the period during which people are most likely to be engaged in activities related to business,
education, active recreation, etc.
declared A-weighted sound power level (L ): statistical maximum A-weighted sound power level for
WAd
manufactured units, taking into account tolerances of production and measurement variance, described in ISO 9296 [2]
NOTE: Typically, L is 0,3 bels higher than the A-weighted sound power level measured on an average
WAd
manufactured unit. L is used for all equipment classes and in the specification of noise emission
WAd
limits. Units: bels.
free field over a reflecting plane: sound field in a homogeneous, isotropic medium in the half-space above an infinite,
rigid plane surface on which the source is located
functional unit: entity of physical equipment, which has been allocated an identification number, capable of
accomplishing a specified task
NOTE 1: A functional unit may be supported by a frame or frames and may be self-enclosed or designed to be
attached to another device.
NOTE 2: An end-use enclosure in the form of a rack, populated with sub-assemblies or other functional units, may
be considered a functional unit whether or not it has a separate identification number.
hemi-anechoic room: room in which a free field over a reflecting plane is obtained
ETSI
9 ETSI EN 300 753 V1.3.1 (2012-01)
high temperature A-weighted sound power level (HL ): statistical maximum A-weighted sound power level for
WAd
manufactured units, taking into account tolerances of production and measurement variance
NOTE: 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 for
WAd
equipment whose operational noise varies with temperature. Units: bels.
high temperature limit: maximum temperature specified for the stated environmental class of the equipment under test
according to the relevant subpart of EN 300 019-1 [3]
industrial: relating to areas, typically, of transient population and heavy manufacturing activity
night-time: part of the day considered to be normal sleeping hours
NOTE: This period includes evening and early morning hours when people are likely to be awake but not yet
fully involved in typical daytime activities.
office: area where individuals are primarily engaged in individual or small group intellectual tasks which require
excellent conditions for task concentration and speech communication
NOTE: A typical example would be a single-person closed office.
power room: area designed to house heavy equipment including, but not limited to, power generation equipment,
heating equipment, and ventilation equipment
NOTE: Typically occupied only for short periods during servicing.
protected area: location intended to be used for rest, recuperation and contemplation
NOTE: 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: areas, typically, in the countryside with low population density
sound power level (L ): logarithm (base 10) of the ratio of a given sound power to the reference sound power
W
NOTE: 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.
sound pressure level (L ): ten times the logarithm (base 10) of the ratio of the time-mean-square sound pressure to the
P
square of the reference sound pressure
NOTE: 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.
telecommunication equipment room: area dedicated to large telecommunication systems
NOTE: Unattended rooms are typically occupied only for service and maintenance activities. These activities
may last for periods of time greater than one hour.
underground vault: sealed underground enclosure which is large enough to be entered for servicing equipment
contained therein
NOTE: Typically occupied only for service and maintenance activities. These activities may last for periods of
time greater than one hour.
urban: relating to areas, typically, in towns and cities with high population density
ETSI
10 ETSI EN 300 753 V1.3.1 (2012-01)
3.2 Symbols
For the purposes of the present document, the following symbols apply:
L sound power level
W
L declared A-weighted sound power level
WAd
L sound pressure level
p
HLWAd high temperature declared A-weighted sound power level
4 Measurement methodology
The measurement methods specified in ISO 7779 [1] and in the basic standards ISO 3741:2010 [7], ISO 3744:2010 [8]
and ISO 3745 [9] 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 the present document 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.
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 clauses 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.
WAd
ETSI
11 ETSI EN 300 753 V1.3.1 (2012-01)
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 of the reference climatic class (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 the following two methods:
• In the first method, the ambie
...

Final draft ETSI EN 300 753 V1.3.1 (2011-11)

European Standard
Equipment Engineering (EE);
Acoustic noise emitted by telecommunications equipment

2 Final draft ETSI EN 300 753 V1.3.1 (2011-11)

Reference
REN/EE-00025
Keywords
acoustic, emission, environment, noise
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
Individual copies of the present document can be downloaded from:
http://www.etsi.org
The present document may be made available in more than one electronic version or in print. In any case of existing or
perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF).
In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive
within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
http://portal.etsi.org/tb/status/status.asp
If you find errors in the present document, please send your comment to one of the following services:
http://portal.etsi.org/chaircor/ETSI_support.asp
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 2011.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and symbols . 8
3.1 Definitions . 8
3.2 Symbols . 10
4 Measurement methodology . 10
5 Installation and operation of equipment . 10
5.1 Equipment installation . 10
5.2 Equipment operation "in-use" . 10
5.2.1 Variable emissions - standard temperature test . 10
5.2.2 Variable emissions - high temperature test . 11
6 Acoustic noise emission limits . 11
7 Information to be recorded . 12
8 Information to be reported . 13
9 Verification of declared A-weighted sound power levels . 13
Annex A (normative): Measurement methods for acoustic noise emission from open air
outdoor equipment . 14
A.1 Scope . 14
A.2 Source directionality. 14
A.3 Installation and operation of equipment . 14
A.3.1 Daytime simulation . 14
A.3.2 Night-time simulation . 14
A.4 Information to be recorded . 15
A.5 Information to be reported . 15
Annex B (informative): Recommended sound power limits for open air outdoor equipment . 16
Annex C (informative): Recommended method for the detection and reporting of prominent
discrete tones . 18
Annex D (informative): Motivation for the present document . 19
Annex E (informative): The relationship between sound power and sound pressure . 20
Annex F (informative): Sound power measurement methods . 21
F.1 Free field over a reflecting plane technique . 21
F.1.1 Concept . 21
F.1.2 Measurement procedure . 21
F.2 Reverberation room technique . 21
F.2.1 Concept . 21
ETSI
4 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
F.2.2 Measurement procedure . 21
F.3 Anechoic and semi-anechoic rooms . 22
F.3.1 Concept . 22
F.3.2 Measurement procedure . 22
History . 23

ETSI
5 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This final draft European Standard (EN) has been produced by ETSI Technical Committee Environmental Engineering
(EE), and is now submitted for the Vote phase of the ETSI standards Two-step Approval Procedure.

Proposed national transposition dates
Date of latest announcement of this EN (doa): 3 months after ETSI publication
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 6 months after doa
Date of withdrawal of any conflicting National Standard (dow): 6 months after doa

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. The present document 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, the present
document 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 the present
document is to specify limits that are applicable to the major installation categories.
ETSI
6 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
The fundamental concern prompting the development of the present document 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 EC Directive 2003/10/EC [4].
The present document 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 the present document as the method for declaring sound power
values. ISO 9296 [2] also specifies a method for verification of declared sound power values.
For further information regarding the motivation for the development of the present document, see annex D.
ETSI
7 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
1 Scope
The present document specifies acoustic noise emission limits for equipment used in telecommunication locations as
specified in the EN 300 019-1 [3] series. The present document covers switching, transmission, power, supervisory, as
well as tariff and billing equipment.
The present document 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], ISO 9296 [2] and in the basic
standards ISO 3741:2010 [7], ISO 3744:2010 [8] and ISO 3745 [9]. 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 [i.1]).
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 the present document. Annex E discusses the
relationship between sound power and sound pressure. Annex F briefly summarizes the sound power measurement
methods used within the present document.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] ISO 7779: "Acoustics -- Measurement of airborne noise emitted by information technology and
telecommunications equipment".
[2] ISO 9296: "Acoustics -- Declared noise emission values of computer and business equipment".
[3] ETSI EN 300 019-1: "Environmental Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment; Part 1: Classification of environmental
conditions".
[4] Directive 2003/10/EC of the European Parliament and of the Council of 6 February 2003 on the
minimum health and safety requirements regarding the exposure of workers to the risks arising
from physical agents (noise).
NOTE: OJ L 42, 15.02.2003 p.38-44.
[5] Void.
[6] ECMA TR/27: "Method for the Prediction of Installation Noise Levels".
ETSI
8 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
[7] ISO 3741:2010: "Acoustics -- Determination of sound power levels and sound energy levels of
noise sources using sound pressure -- Precision methods for reverberation test rooms".
[8] ISO 3744:2010: "Acoustics -- Determination of sound power levels and sound energy levels of
noise sources using sound pressure -- Engineering methods for an essentially free field over a
reflecting plane".
[9] ISO 3745:2003: "Acoustics -- Determination of sound power levels of noise sources using sound
pressure -- Precision methods for anechoic and hemi-anechoic rooms".
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI ETR 116 (1994): "Human Factors (HF); Human factors guidelines for ISDN Terminal
equipment design".
3 Definitions and symbols
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
A-weighting filter: response characteristic of a filter used in acoustic measurement systems which attenuates low
frequency and high frequency acoustic energy
NOTE: This filter is used to provide a frequency response characteristic similar to that of the human auditory
system.
business area: area where the principal activity is office / clerical work or similar activities
NOTE: 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.
daytime: part of the day considered to extend over normal waking hours
NOTE: Typically, the period during which people are most likely to be engaged in activities related to business,
education, active recreation, etc.
declared A-weighted sound power level (L ): statistical maximum A-weighted sound power level for
WAd
manufactured units, taking into account tolerances of production and measurement variance, described in ISO 9296 [2]
NOTE: Typically, L is 0,3 bels higher than the A-weighted sound power level measured on an average
WAd
manufactured unit. L is used for all equipment classes and in the specification of noise emission
WAd
limits. Units: bels.
free field over a reflecting plane: sound field in a homogeneous, isotropic medium in the half-space above an infinite,
rigid plane surface on which the source is located
functional unit: entity of physical equipment, which has been allocated an identification number, capable of
accomplishing a specified task
NOTE 1: A functional unit may be supported by a frame or frames and may be self-enclosed or designed to be
attached to another device.
NOTE 2: An end-use enclosure in the form of a rack, populated with sub-assemblies or other functional units, may
be considered a functional unit whether or not it has a separate identification number.
hemi-anechoic room: room in which a free field over a reflecting plane is obtained
ETSI
9 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
high temperature A-weighted sound power level (HL ): statistical maximum A-weighted sound power level for
WAd
manufactured units, taking into account tolerances of production and measurement variance
NOTE: 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 for
WAd
equipment whose operational noise varies with temperature. Units: bels.
high temperature limit: maximum temperature specified for the stated environmental class of the equipment under test
according to the relevant subpart of EN 300 019-1 [3]
industrial: relating to areas, typically, of transient population and heavy manufacturing activity
night-time: part of the day considered to be normal sleeping hours
NOTE: This period includes evening and early morning hours when people are likely to be awake but not yet
fully involved in typical daytime activities.
office: area where individuals are primarily engaged in individual or small group intellectual tasks which require
excellent conditions for task concentration and speech communication
NOTE: A typical example would be a single-person closed office.
power room: area designed to house heavy equipment including, but not limited to, power generation equipment,
heating equipment, and ventilation equipment
NOTE: Typically occupied only for short periods during servicing.
protected area: location intended to be used for rest, recuperation and contemplation
NOTE: 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: areas, typically, in the countryside with low population density
sound power level (L ): logarithm (base 10) of the ratio of a given sound power to the reference sound power
W
NOTE: 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.
sound pressure level (L ): ten times the logarithm (base 10) of the ratio of the time-mean-square sound pressure to the
P
square of the reference sound pressure
NOTE: 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.
telecommunication equipment room: area dedicated to large telecommunication systems
NOTE: Unattended rooms are typically occupied only for service and maintenance activities. These activities
may last for periods of time greater than one hour.
underground vault: sealed underground enclosure which is large enough to be entered for servicing equipment
contained therein
NOTE: Typically occupied only for service and maintenance activities. These activities may last for periods of
time greater than one hour.
urban: relating to areas, typically, in towns and cities with high population density
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10 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
3.2 Symbols
For the purposes of the present document, the following symbols apply:
L sound power level
W
L declared A-weighted sound power level
WAd
L sound pressure level
p
HLWAd high temperature declared A-weighted sound power level
4 Measurement methodology
The measurement methods specified in ISO 7779 [1] and in the basic standards ISO 3741:2010 [7], ISO 3744:2010 [8]
and ISO 3745 [9] 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 the present document 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.
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 clauses 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.
WAd
ETSI
11 Final draft ETSI EN 300 753 V1.3.1 (2011-11)
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 of the reference climatic class (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 the foll
...

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Equipment Engineering (EE) - Acoustic noise emitted by telecommunications equipment33.050.01Telekomunikacijska terminalska oprema na splošnoTelecommunication terminal equipment in general17.140.20Emisija hrupa naprav in opremeNoise emitted by machines and equipmentICS:Ta slovenski standard je istoveten z:EN 300 753 Version 1.3.1SIST EN 300 753 V1.3.1:2012en01-april-2012SIST EN 300 753 V1.3.1:2012SLOVENSKI
STANDARD
European Standard SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 2
Reference REN/EE-00025 Keywords acoustic, emission, environment, noise ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE
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Important notice Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http://portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: http://portal.etsi.org/chaircor/ETSI_support.asp 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 2012. All rights reserved.
DECTTM, PLUGTESTSTM, UMTSTM and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association. SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 3 Contents Intellectual Property Rights . 5 Foreword . 5 Introduction . 5 1 Scope . 7 2 References . 7 2.1 Normative references . 7 2.2 Informative references . 8 3 Definitions and symbols . 8 3.1 Definitions . 8 3.2 Symbols . 10 4 Measurement methodology . 10 5 Installation and operation of equipment . 10 5.1 Equipment installation . 10 5.2 Equipment operation "in-use" . 10 5.2.1 Variable emissions - standard temperature test . 10 5.2.2 Variable emissions - high temperature test . 11 6 Acoustic noise emission limits . 11 7 Information to be recorded . 12 8 Information to be reported . 13 9 Verification of declared A-weighted sound power levels . 13 Annex A (normative): Measurement methods for acoustic noise emission from open air outdoor equipment . 14 A.1 Scope . 14 A.2 Source directionality. 14 A.3 Installation and operation of equipment . 14 A.3.1 Daytime simulation . 14 A.3.2 Night-time simulation . 14 A.4 Information to be recorded . 15 A.5 Information to be reported . 15 Annex B (informative): Recommended sound power limits for open air outdoor equipment . 16 Annex C (informative): Recommended method for the detection and reporting of prominent discrete tones . 18 Annex D (informative): Motivation for the present document . 19 Annex E (informative): The relationship between sound power and sound pressure . 20 Annex F (informative): Sound power measurement methods . 21 F.1 Free field over a reflecting plane technique . 21 F.1.1 Concept . 21 F.1.2 Measurement procedure . 21 F.2 Reverberation room technique . 21 F.2.1 Concept . 21 SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 4 F.2.2 Measurement procedure . 21 F.3 Anechoic and semi-anechoic rooms . 22 F.3.1 Concept . 22 F.3.2 Measurement procedure . 22 History . 23
ETSI ETSI EN 300 753 V1.3.1 (2012-01) 5 Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://ipr.etsi.org). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (EN) has been produced by ETSI Technical Committee Environmental Engineering (EE).
National transposition dates Date of adoption of this EN: 16 January 2012 Date of latest announcement of this EN (doa): 30 April 2012 Date of latest publication of new National Standard or endorsement of this EN (dop/e):
31 October 2012 Date of withdrawal of any conflicting National Standard (dow): 31 October 2012
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. The present document 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, the present document 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 the present document is to specify limits that are applicable to the major installation categories. SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 6 The fundamental concern prompting the development of the present document 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 EC Directive 2003/10/EC [4]. The present document 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 the present document as the method for declaring sound power values. ISO 9296 [2] also specifies a method for verification of declared sound power values. For further information regarding the motivation for the development of the present document, see annex D. SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 7 1 Scope The present document specifies acoustic noise emission limits for equipment used in telecommunication locations as specified in the EN 300 019-1 [3] series. The present document covers switching, transmission, power, supervisory, as well as tariff and billing equipment.
The present document 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], ISO 9296 [2] and in the basic standards ISO 3741:2010 [7], ISO 3744:2010 [8] and ISO 3745 [9]. 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 [i.1]). 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 the present document. Annex E discusses the relationship between sound power and sound pressure. Annex F briefly summarizes the sound power measurement methods used within the present document. 2 References References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the reference document (including any amendments) applies. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. 2.1 Normative references The following referenced documents are necessary for the application of the present document. [1] ISO 7779: "Acoustics -- Measurement of airborne noise emitted by information technology and telecommunications equipment". [2] ISO 9296: "Acoustics -- Declared noise emission values of computer and business equipment". [3] ETSI EN 300 019-1: "Environmental Engineering (EE); Environmental conditions and environmental tests for telecommunications equipment; Part 1: Classification of environmental conditions". [4] Directive 2003/10/EC of the European Parliament and of the Council of 6 February 2003 on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (noise). NOTE: OJ L 42, 15.02.2003 p.38-44. [5] Void. [6] ECMA TR/27: "Method for the Prediction of Installation Noise Levels". SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 8 [7] ISO 3741:2010: "Acoustics -- Determination of sound power levels and sound energy levels of noise sources using sound pressure -- Precision methods for reverberation test rooms". [8] ISO 3744:2010: "Acoustics -- Determination of sound power levels and sound energy levels of noise sources using sound pressure -- Engineering methods for an essentially free field over a reflecting plane". [9] ISO 3745:2003: "Acoustics -- Determination of sound power levels of noise sources using sound pressure -- Precision methods for anechoic and hemi-anechoic rooms". 2.2 Informative references The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area. [i.1] ETSI ETR 116 (1994): "Human Factors (HF); Human factors guidelines for ISDN Terminal equipment design". 3 Definitions and symbols 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: A-weighting filter: response characteristic of a filter used in acoustic measurement systems which attenuates low frequency and high frequency acoustic energy NOTE: This filter is used to provide a frequency response characteristic similar to that of the human auditory system.
business area: area where the principal activity is office / clerical work or similar activities NOTE: 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.
daytime: part of the day considered to extend over normal waking hours NOTE: Typically, the period during which people are most likely to be engaged in activities related to business, education, active recreation, etc. declared A-weighted sound power level (LWAd): statistical maximum A-weighted sound power level for manufactured units, taking into account tolerances of production and measurement variance, described in ISO 9296 [2]
NOTE: Typically, LWAd is 0,3 bels higher than the A-weighted sound power level measured on an average manufactured unit. LWAd is used for all equipment classes and in the specification of noise emission limits. Units: bels. free field over a reflecting plane: sound field in a homogeneous, isotropic medium in the half-space above an infinite, rigid plane surface on which the source is located functional unit: entity of physical equipment, which has been allocated an identification number, capable of accomplishing a specified task NOTE 1: A functional unit may be supported by a frame or frames and may be self-enclosed or designed to be attached to another device. NOTE 2: An end-use enclosure in the form of a rack, populated with sub-assemblies or other functional units, may be considered a functional unit whether or not it has a separate identification number. hemi-anechoic room: room in which a free field over a reflecting plane is obtained SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 9 high temperature A-weighted sound power level (HLWAd): statistical maximum A-weighted sound power level for manufactured units, taking into account tolerances of production and measurement variance NOTE: 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]. HLWAd is used for equipment whose operational noise varies with temperature. Units: bels. high temperature limit: maximum temperature specified for the stated environmental class of the equipment under test according to the relevant subpart of EN 300 019-1 [3] industrial: relating to areas, typically, of transient population and heavy manufacturing activity night-time: part of the day considered to be normal sleeping hours NOTE: This period includes evening and early morning hours when people are likely to be awake but not yet fully involved in typical daytime activities. office: area where individuals are primarily engaged in individual or small group intellectual tasks which require excellent conditions for task concentration and speech communication NOTE: A typical example would be a single-person closed office. power room: area designed to house heavy equipment including, but not limited to, power generation equipment, heating equipment, and ventilation equipment NOTE: Typically occupied only for short periods during servicing. protected area: location intended to be used for rest, recuperation and contemplation NOTE: 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: areas, typically, in the countryside with low population density sound power level (LW): logarithm (base 10) of the ratio of a given sound power to the reference sound power NOTE: 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. sound pressure level (LP): ten times the logarithm (base 10) of the ratio of the time-mean-square sound pressure to the square of the reference sound pressure NOTE: 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. telecommunication equipment room: area dedicated to large telecommunication systems NOTE: Unattended rooms are typically occupied only for service and maintenance activities. These activities may last for periods of time greater than one hour. underground vault: sealed underground enclosure which is large enough to be entered for servicing equipment contained therein NOTE: Typically occupied only for service and maintenance activities. These activities may last for periods of time greater than one hour. urban: relating to areas, typically, in towns and cities with high population density SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 10 3.2 Symbols For the purposes of the present document, the following symbols apply: LW sound power level LWAd declared A-weighted sound power level Lp sound pressure level HLWAd high temperature declared A-weighted sound power level
4 Measurement methodology The measurement methods specified in ISO 7779 [1] and in the basic standards ISO 3741:2010 [7], ISO 3744:2010 [8] and ISO 3745 [9] 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 the present document 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.
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 clauses 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 (LWAd) for the equipment. SIST EN 300 753 V1.3.1:2012

ETSI ETSI EN 300 753 V1.3.1 (2012-01) 11 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
...