Heat exchangers - Forced convection air cooled refrigerant condensers and dry coolers - Sound measurement

This European Standard is one of a series of European Standards dedicated to air-cooled heat exchangers.
   forced convection air cooled refrigerant condensers as specified in EN 327;
   forced convection unit air coolers for refrigeration as specified in EN 328;
   air cooled liquid coolers "dry coolers" as specified in EN 1048.
This standard provides information for assessing and presenting the acoustic emission characteristics of heat exchangers under stationary operating conditions.
This European Standard is applicable to selfstanding forced convection air cooled refrigerant condensers and air cooled liquid coolers "dry coolers" and air coolers.

Wärmeübertrager - Ventilatorbelüftete Kältemittelverflüssiger und Trockenkühltürme - Schallmessung

1.1   Allgemeines
Dieses Dokument ist Bestandteil einer Normenreihe für luftgekühlte Wärmeaustauscher.
—   ventilatorbelüfteter Kältemittelverflüssiger, wie in EN 327 angegeben;
—   Ventilatorluftkühler zum Kühlen, wie in EN 328 angegeben;
—   luftgekühlte Flüssigkeitskühler („Trockenkühltürme“), wie in EN 1048 angegeben.
Dieses Dokument enthält Informationen zur Bewertung und Darstellung akustischer Merkmale eines Wärmeaustauschers unter stationären Betriebsbedingungen.
Dieses Dokument gilt für selbststehende ventilatorbelüftete Kältemittelverflüssiger und luftgekühlte Flüssigkeitskühler („Trockenkühltürme“) sowie Luftkühler.
1.2   Größe der Quelle
Das in EN ISO 3744, EN ISO 3745, EN ISO 3746, EN ISO 9614 1, EN ISO 9614 2 und EN ISO 9614 3 angegebene Verfahren gilt für Geräuschquellen jeglicher Größen. Einschränkungen zur Größe der Quelle sind unter 1.3 der EN ISO 3741:2010, EN ISO 3743 1:2010 und EN ISO 3743 2:2009 angegeben.
1.3   Prüfgegenstand
Dieses Dokument enthält Verfahren für die Ermittlung des Schallleistungspegels von Geräten. Einige dieser Verfahren sind speziell darauf ausgelegt Ergebnisse mit geringen Unsicherheiten unter Anwendung von „Präzisionsverfahren“ (Klasse 1) oder „Technischen Verfahren“ (Klasse 2) unter streng geregelten Betriebsbedingungen zu erzeugen. Diese Ergebnisse sind für die Zertifizierung, Etikettierung und Kennzeichnung geeignet.
Dieses Dokument befasst sich mit objektiven Verfahren zur Festlegung der Schallleistungspegel LW, der in Dezibel (dB) ausgedrückt wird, in Bezug auf eine Schallleistung von einem Picowatt (1 pW) der Luftschallemission innerhalb eines interessierenden angegebenen Frequenzbereichs und unter vorgegebenen Betriebsbedingungen des zu messenden Geräts:
—   A-bewerteter Schallleistungspegel LWA;
—   spektrale Schallleistungspegel;
—   Emissionsschalldruckpegel am Arbeitsplatz LpA.

Echangeurs thermiques - Aérocondenseur à convection forcée et batterie froide - Mesurage du bruit

1.1   Généralités
La présente Norme européenne fait partie d'une série de Normes européennes relatives aux échangeurs thermiques à air.
-   les aérocondenseurs à convection forcée tels que spécifiés dans l’EN 327 ;
-   les aérofrigorifères à convection forcée pour la réfrigération tels que spécifiés dans l’EN 328 ;
-   les refroidisseurs de liquide à convection forcée "aéroréfrigérant sec" tels que spécifiés dans l’EN 1048 ;
La présente Norme européenne fournit les informations pour l'évaluation et la présentation des caractéristiques acoustiques des échangeurs thermiques dans des conditions de fonctionnement stationnaires.
La présente Norme européenne s’applique aux aérocondenseurs à convection forcée et aux refroidisseurs de liquide à convection forcée "aéroréfrigérant sec" et aérofrigorifères autonomes.
1.2   Taille de la source
La méthode spécifiée dans l’EN ISO 3744, l’EN ISO 3745, l’EN ISO 3746, l’EN ISO 9614-1 et l’EN ISO 9614 2 s’applique aux sources de bruit de toute taille. Les limites de taille de la source sont données en 1.3 de l'EN ISO 3741:2010, l'EN ISO 3743-1:2010 et l'EN ISO 3743-2:2009.
1.3   Objet
La présente Norme européenne fournit des moyens pour déterminer le niveau de puissance acoustique des appareils. Certains sont spécifiquement adaptés pour fournir des résultats avec des incertitudes faibles, à l'aide de méthodes acoustiques de classe laboratoire ou de classe expertise dans des conditions de travail hautement contrôlées. Ces résultats sont adaptés à des fins de certification, d'étiquetage et de marquage.
La présente norme donne des méthodes objectives pour déterminer les niveaux de puissance acoustique LW, exprimés en décibels (dB) en référence à la puissance acoustique d'un picowatt (1 pW), du bruit aérien dans la plage de fréquence d'intérêt spécifiée et pour les conditions de fonctionnement prescrites du dispositif à mesurer :
-   le niveau de puissance acoustique pondéré A, LWA ;
-   les niveaux de spectre de la puissance acoustique ;
- le niveau de pression acoustique d’émission sur le lieu de travail, LpA.

Prenosniki toplote - Zračno hlajeni kondenzatorji in hladilniki kapljevine s prisilno konvekcijo - Merjenje hrupa

Ta evropski standard spada v skupino evropskih standardov, namenjenih zračno hlajenim prenosnikom toplote:
-   zračno hlajenim kondenzatorjem hladiva s prisilno konvekcijo, kot je opredeljeno v standardu EN 327;
-   hladilnikom zraka s prisilno konvekcijo za hlajenje, kot je opredeljeno v standardu EN 328;
-   zračno hlajenim hladilnikom tekočin, kot je opredeljeno v standardu EN 1048.
Ta standard podaja informacije za ocenjevanje in predstavitev karakteristik akustičnih emisij prenosnikov toplote pri stacionarnem obratovanju. Ta evropski standard se uporablja za samostoječe zračno hlajene kondenzatorje in hladilnike kapljevine ter hladilnike zraka s prisilno konvekcijo.

General Information

Status
Published
Public Enquiry End Date
04-Dec-2017
Publication Date
06-Nov-2019
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
20-Sep-2019
Due Date
25-Nov-2019
Completion Date
07-Nov-2019

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SLOVENSKI STANDARD
SIST EN 13487:2019
01-december-2019
Nadomešča:
SIST EN 13487:2004

Prenosniki toplote - Zračno hlajeni kondenzatorji in hladilniki kapljevine s prisilno

konvekcijo - Merjenje hrupa

Heat exchangers - Forced convection air cooled refrigerant condensers and dry coolers -

Sound measurement

Wärmeübertrager - Ventilatorbelüftete Kältemittelverflüssiger und Trockenkühltürme -

Schallmessung
Echangeurs thermiques - Aérocondenseur à convection forcée et batterie froide -
Mesurage du bruit
Ta slovenski standard je istoveten z: EN 13487:2019
ICS:
17.140.20 Emisija hrupa naprav in Noise emitted by machines
opreme and equipment
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
SIST EN 13487:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 13487:2019
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SIST EN 13487:2019
EN 13487
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2019
EUROPÄISCHE NORM
ICS 17.140.20; 27.060.30 Supersedes EN 13487:2003
English Version
Heat exchanger - Forced convection air cooled refrigerant
condensers and dry coolers - Sound measurement

Echangeurs thermiques - Aérocondenseur à convection Wärmeübertrager - Ventilatorbelüftete

forcée et batterie froide - Mesurage du bruit Kältemittelverflüssiger und Trockenkühltürme -

Schallmessung
This European Standard was approved by CEN on 17 June 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13487:2019 E

worldwide for CEN national Members.
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SIST EN 13487:2019
EN 13487:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 4

Introduction .................................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

1.1 General ................................................................................................................................................................ 6

1.2 Size of source .................................................................................................................................................... 6

1.3 Object ................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 7

3 Terms and definitions ................................................................................................................................... 8

4 Description of apparatus types ............................................................................................................... 11

5 Sound power determination .................................................................................................................... 13

5.1 General ............................................................................................................................................................. 13

5.2 Microphone positions and measurement surface for essentially free field conditions

over reflecting plane and sound intensity measurements ........................................................... 13

5.3 Microphone positions in hard-walled test rooms or special reverberation test rooms .... 14

5.4 Background noise ........................................................................................................................................ 14

5.5 Calculation of sound power ...................................................................................................................... 14

6 Emission sound pressure level determination ................................................................................. 14

7 Installation and mounting conditions .................................................................................................. 15

7.1 Location ........................................................................................................................................................... 15

7.2 Mounting ......................................................................................................................................................... 15

8 Operating conditions .................................................................................................................................. 15

8.1 General ............................................................................................................................................................. 15

8.2 Supply of electrical energy........................................................................................................................ 15

8.3 Fan speed setting .......................................................................................................................................... 16

9 Measurement uncertainties ..................................................................................................................... 16

10 Information to be recorded ...................................................................................................................... 16

10.1 General ............................................................................................................................................................. 16

10.2 Noise source under test ............................................................................................................................. 16

10.3 Test environment ......................................................................................................................................... 17

10.4 Instrumentation ........................................................................................................................................... 17

10.5 Acoustical data .............................................................................................................................................. 17

11 Information to be reported ...................................................................................................................... 18

11.1 General ............................................................................................................................................................. 18

11.2 Noise source under test ............................................................................................................................. 18

11.3 Test environment ......................................................................................................................................... 18

11.4 Instrumentation ........................................................................................................................................... 18

11.5 Acoustical data .............................................................................................................................................. 19

12 Declaration and verification of noise emission values ................................................................... 19

Annex A (normative) Calculation of the sound power with different partial measuring

surfaces in accordance with EN ISO 3744 and EN ISO 3746 ......................................................... 20

Annex B (normative) Simplified arrangement of measuring points ...................................................... 21

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Annex C (informative) Example of dual-number declaration ................................................................... 25

Annex D (normative) Deviations from the test subject ................................................................................ 26

Annex E (informative) Directivity ........................................................................................................................ 27

Bibliography ................................................................................................................................................................. 28

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EN 13487:2019 (E)
European foreword

This document (EN 13487:2019) has been prepared by Technical Committee CEN/TC 110 “Heat

exchangers”, the secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by February 2020 and conflicting national standards shall

be withdrawn at the latest by February 2020.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 13487:2003.
The main changes compared to the previous edition are:
a) the Scope was completely revised;
b) the Normative references were updated;
c) Terms and Definitions were updated and new terms were introduced;
d) the whole document, including Annexes, was completely revised and rearranged.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
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EN 13487:2019 (E)
Introduction
This document is one of a series dedicated to heat exchangers.

This document provides information for assessing and presenting the acoustic characteristics of heat

exchangers in fan operation.

This document also provides information necessary for specifying and selecting the product which best

suits the needs of the purchaser.
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EN 13487:2019 (E)
1 Scope
1.1 General
This document is one of a series dedicated to air-cooled heat exchangers.
— forced convection air cooled refrigerant condensers as specified in EN 327;
— forced convection unit air coolers for refrigeration as specified in EN 328;
— air cooled liquid coolers "dry coolers" as specified in EN 1048.

This document provides information for assessing and presenting the acoustic emission characteristics

of heat exchangers under stationary operating conditions.

This document is applicable to selfstanding forced convection air cooled refrigerant condensers and air

cooled liquid coolers "dry coolers" and air coolers.
1.2 Size of source

The method specified in EN ISO 3744, EN ISO 3745, EN ISO 3746, EN ISO 9614-1, EN ISO 9614-2 and

EN ISO 9614-3 is applicable to noise sources of any size. Limitations for the size of the source are given

in 1.3 of EN ISO 3741:2010, EN ISO 3743-1:2010 and EN ISO 3743-2:2009.
1.3 Object

This document offers ways to determine the sound power level of units. Some of them are specifically

adapted to provide results with low uncertainties, by using laboratory class or engineering class

acoustic methods under highly controlled working conditions. Those results are suitable for

certification, labeling and marking purposes.

This document is concerned with objective methods for determining sound power levels L , expressed

in decibels (dB) with reference to a sound power of one picowatt (1 pW), of airborne acoustical noise

within the specified frequency range of interest and for prescribed operating conditions of the

appliance to be measured:
— A-weighted sound power level, L ;
— spectral sound power levels;
— emission sound pressure level at workplace, L .
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EN 13487:2019 (E)
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 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 (ISO 3741:2010)

EN ISO 3743-1:2010, Acoustics - Determination of sound power levels and sound energy levels of noise

sources using sound pressure - Engineering methods for small movable sources in reverberant fields - Part

1: Comparison method for a hard-walled test room (ISO 3743-1:2010)

EN ISO 3743-2:2009, Acoustics - Determination of sound power levels of noise sources using sound

pressure - Engineering methods for small, movable sources in reverberant fields - Part 2: Methods for

special reverberation test rooms (ISO 3743-2:1994)

EN 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

(ISO 3744:2010)

EN ISO 3745:2012/A1:2017, Acoustics - Determination of sound power levels and sound energy levels of

noise sources using sound pressure - Precision methods for anechoic rooms and hemi-anechoic rooms -

Amendment 1 (ISO 3745:2012/Amd 1:2017)

EN ISO 3746:2010, Acoustics - Determination of sound power levels and sound energy levels of noise

sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting

plane (ISO 3746:2010)

EN ISO 4871, Acoustics - Declaration and verification of noise emission values of machinery

and equipment (ISO 4871)

EN ISO 9614-1:2009, Acoustics - Determination of sound power levels of noise sources using sound

intensity - Part 1: Measurement at discrete points (ISO 9614-1:1993)

EN ISO 9614-2:1996, Acoustics - Determination of sound power levels of noise sources using sound

intensity - Part 2: Measurement by scanning (ISO 9614-2:1996)

EN ISO 9614-3:2009, Acoustics - Determination of sound power levels of noise sources using sound

intensity - Part 3: Precision method for measurement by scanning (ISO 9614-3:2002)

EN ISO 11203:2009, Acoustics - Noise emitted by machinery and equipment - Determination of emission

sound pressure levels at a work station and at other specified positions from the sound power level (ISO

11203:1995)

ISO 7574-4, Acoustics — Statistical methods for determining and verifying stated noise emission values of

machinery and equipment — Part 4: Methods for stated values for batches of machines

EN 60038, CENELEC standard voltages (IEC 60038)
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EN 13487:2019 (E)
3 Terms and definitions

For the purposes of this document, the terms and definitions pertinent to the determination of sound

power levels given in EN ISO 3741, EN ISO 3743-1, EN ISO 3743-2, EN ISO 3744, EN ISO 3746,

EN ISO 9614-1, EN ISO 9614-2 and EN ISO 9614-3 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
forced convection air cooled refrigerant condenser

refrigeration system component that condenses refrigerant vapour by rejecting heat to air, which is

mechanically circulated over its dry heat transfer surface by integral fans and fan drives

Note 1 to entry: In the following "forced convection air cooled refrigerant condenser" is referred to as

"apparatus".
[SOURCE: EN 327:2014, 3.1]

Note 2 to entry: The heat transfer coil includes distributing and collecting headers.

3.2
forced convection air cooled liquid cooler
dry cooler

self contained system that cools a single phase liquid by rejecting sensible heat via a heat exchanger to

air that is mechanically circulated by integral fans

Note 1 to entry: In the following "forced convection air cooled liquid cooler; dry cooler" is referred to as

"apparatus".
[SOURCE: EN 1048:2014, 3.1]
3.3
forced convection unit air cooler

refrigeration system component transferring heat from air to a refrigerant or liquid, the air is

mechanically circulated over the heat transfer surface by integral fan(s) and fan drive(s)

Note 1 to entry: The heat transfer coil includes refrigerant distributing and collecting headers.

Note 2 to entry: In the following “forced convection unit air cooler” is referred to as “apparatus”.

3.4
emission sound pressure level

ten times the logarithm to the base 10 of the ratio of the square of the emission sound pressure, p, to the

square of the reference value, p , measured with a particular time weighting and a particular frequency

weighting

Note 1 to entry: Time and frequency weightings are selected from those defined in EN 61672-1 expressed in

decibels:
L = 10lg dB
where the reference value, p , is 20 μPa.
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EN 13487:2019 (E)

Note 2 to entry: The emission sound pressure level shall be determined at a specified position in accordance

with either a test code for a specific family of machines or, if no test code exists, a method that complies with the

EN ISO 11200 series.
[SOURCE: EN ISO 11200:2014, 3.3]
3.5
sound power level

ten times the logarithm to the base 10 of the ratio of the sound power of a source, P, to a reference

value, P , expressed in decibels
L = 10lg dB
where the reference value, P , is 1 pW

Note 1 to entry: If a specific frequency weighting as specified in IEC 61672-1 and/or specific frequency bands

are applied, this is indicated by appropriate subscripts; e.g. L denotes the A-weighted sound power level.

Note 2 to entry: This definition is technically in accordance with ISO 80000-8:2007[2], 8-23.

[SOURCE: ISO/TR 25417:2007, 2.9 and EN ISO 3744:2010, 3.21]
3.6
frequency range of interest

for general purposes, the frequency range of octave bands with nominal mid-band frequencies from

125 Hz to 8 000 Hz (including one-third octave bands with mid-band frequencies from 100 Hz to

10 000 Hz)

Note 1 to entry: For special purposes, the frequency range can be extended or reduced, provided that the test

environment and instrument specifications are satisfactory for use over the modified frequency range. Changes to

the frequency range of interest are included in the test report.
[SOURCE: EN ISO 3744:2010, 3.9]

Note 2 to entry: For sources which emit sound at predominantly high or low frequencies, the frequency range of

interest can be extended to include these frequencies.
3.7
reference box

hypothetical right parallelepiped terminating on the reflecting plane(s) on which the noise source

under test is located, that just encloses the source including all the significant sound radiating

components and any test table on which the source is mounted

Note 1 to entry: If required, the smallest possible test table can be used for compatibility with emission sound

pressure measurements at bystander positions in accordance with, for example, EN ISO 11201.

[SOURCE: EN ISO 3744:2010, 3.10]
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EN 13487:2019 (E)

Note 2 to entry: The reference box encloses the whole casing, including, if applicable, its normal supporting legs,

fans, piping cover plates (see mark 1 in Figure 1) and control/junction boxes (see mark 2 in Figure 1).

Refrigerant/liquid connections, headers (collectors) and electrical supply cables are not taken into account when

determining the reference box. A typical model is given in Figure 1.
Key
1 piping cover plate
2 control/junction box
Figure 1 — Reference box
3.8
measurement surface

hypothetical surface of area, S, on which the microphone positions are located at which the sound

pressure levels are measured, enveloping the noise source under test and terminating on the reflecting

plane(s) on which the source is located
[SOURCE: EN ISO 3744:2010, 3.14]
3.9
background noise
noise from all sources other than the source under test

Note 1 to entry: Background noise includes contributions from airborne sound, noise from structure-borne

vibration, and electrical noise in the instrumentation.
[SOURCE: EN ISO 3744:2010, 3.15]
3.10
module

geometrically similar group of components from which, when multiplied by an integer number, an

apparatus is built
Note 1 to entry: A module typically comprises:
— fan with motor;
— a heat exchanger coil;

— a casing which ensures the conduction of the air flow as intended, including supporting legs for vertical

air flow.
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EN 13487:2019 (E)

For the purposes of this standard, the significant characteristics of a module are:

— size of the fan and its arrangement relative to the heat exchanger;
— speed of the fan;
— fin and tube geometry;
— air inlet area of the heat exchanger coil;
— depth of the coil in direction of the air flow (number of rows deep).
3.11
test subject

apparatus with all parts necessary to function and in standard design without accessories

Note 1 to entry: This applies especially to the supporting legs (where applicable) and the heat exchanger coil.

3.12
usual test installation
maximum supporting leg height is lower than 1,5 times the fan diameter
4 Description of apparatus types

The object to be measured is the heat exchanger, presented by the cooling element, fan, gearing-

elements and the motor. In case of excluding parts noise emitting elements of the object; it has to be

reported in Clause 11. Typical models of heat exchangers are given in Figure 2.
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EN 13487:2019 (E)
a) Induced draught – Horizontal construction
b) Forced draught – Horizontal construction
c) Induced draught – Two heat exchangers arranged in parallel
d) Induced draught – Two heat exchangers arranged in V shape
e) Induced draught – Vertical construction
f) Forced draught – Vertical construction
g) Forced draught – Two heat exchangers arranged in parallel
h) Forced draught – Two heat exchangers arranged in A-shape-
Figure 2 — Typical heat exchanger constructions
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EN 13487:2019 (E)

In the case of electrical supply by an external frequency converter, the noise radiated by the converter

is excluded from the scope of this document; only the effect of non-sinusoidal voltage and current

within the machine is to be taken into account.

Auxiliary components required for the operation of the machine should be included when integrated

with the machine. When these components are separately mounted, they shall not be included as part of

the machine under test.
5 Sound power determination
5.1 General

The sound power radiated by the apparatus shall be determined on the basis of one of the following

basic standards:
— accuracy grade 1: EN ISO 3741, EN ISO 3745, EN ISO 9614-1, EN ISO 9614-3;

— accuracy grade 2: EN ISO 3743-1, EN ISO 3743-2, EN ISO 3744, EN ISO 9614-1, EN ISO 9614-2;

— accuracy grade 3: EN ISO 3746, EN ISO 9614-1, EN ISO 9614-2.

NOTE EN ISO 3740 can be used as guideline, to choose the best suitable basic standard for the measurement.

The measuring period shall be selected in accordance with the chosen method.

When undertaking measurements in accordance with EN ISO 9614-1, EN ISO 9614-2 and EN ISO 9614-3

the reading for the 8 kHz octave band is accepted.

Where an apparatus is used for vertical and horizontal air flow direction, the measurement with

vertical air flow direction is used as the basis for the evaluation of the sound data.

5.2 Microphone positions and measurement surface for essentially free field conditions

over reflecting plane and sound intensity measurements
5.2.1 General

The measurement surface is parallelepiped and enveloping the reference box in which all noise emitting

parts are included. Parts which are stick out of the reference box and are not noise emitting parts of the

object under test do not need to be considered. The measurement surface follows this reference box in a

distance d and ends on the reflecting plane.
The distance d between the reference box and the measuring surface shall be 1 m.

In exceptional cases (clear definable partial sound power sources of the heat exchanger complex) the

overall sound power level can be determined with partial sound power sources. In this case, all single

noise sources are covered with partial measurement surfaces.

The measurement points should be uniformly positioned on the measurement surface according to the

basic standard in use. For larger test objects, the number of measurement points will increase. A

simplified arrangement of the measurement points can be suitable, if comparison measurements show

that the sound field is uniform and the final result should generate similar or higher values than

measurements with entire number of measurement points.
Microphones shall be equipped with proper wind shields or nose cones.
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5.2.2 Usual test installation with simplified arrangement of measurement points

If the requirements for simplified arrangement of measuring points for class 2 and class 3 are fulfilled,

the following measurement points can be used:

— Annex B, B.1 for apparatus with vertical air flow types according to Figure 2a), Figure 2b), Figure

2c) and Figure 2d);

— Annex B, B.2 for apparatus with horizontal air flow types according to Figure 2e), 2f), 2g) and 2h).

NOTE It has been shown, that for usual test installation according to 3.12, the comparison of measurements

between the standard measurement points and the simplified arranged measurement points described in Annex B

generate similar or higher values.
5.2.3 Special test installation

For an apparatus with a fan arrangement and air flow, different from the usual test installation, the

measuring points shall be chosen analogous to the arrangement in accordance with basic standard in

use.

5.3 Microphone positions in hard-walled test rooms or special reverberation test rooms

The requirements in 8.1.2 of EN ISO 3741:2010, 7.3 of EN ISO 3743-1:2010 and EN ISO 3743-2:2009

shall be followed.
The microphones shall be equipped with proper wind shields.
5.4 Background noise

The background noise shall be measured with the test subject installed but not operating. Auxiliary

devices necessary for the operation of the test installation shall be in operation during the

measurement of background noise.

If the background noise is unsteady, the background noise shall be measured immediately before and

after testing the apparatus. The average value shall be used.
5.5 Calculation of sound power

The sound power level shall be determined according to the standard, which was used to perform the

noise measurement.

In case of using the partial measurement surfaces, a method of calculating the sound power level from

partial measurement surfaces is described in Annex A of this standard.

The A-weighted overall sound power level L shall be calculated from the values in the ⅓-octave

frequency band or octave frequency band.
6 Emission sound pressure level determination

In this document, the emission sound pressure level L is determined in accordance with

EN ISO 11203. No additional measurements are necessary for the determination. As defined by

EN ISO 1
...

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