EN 13487:2019

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

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 LW, 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, LWA;
-   spectral sound power levels;
-   emission sound pressure level at workplace, LpA.

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
• Publication Date: 06-Aug-2019
• Withdrawal Date: 28-Feb-2020
• ICS: 17.140.20 - Noise emitted by machines and equipment
• ICS: 27.060.30 - Boilers and heat exchangers
• Technical Committee: CEN/TC 110 - Heat exchangers
• Drafting Committee: CEN/TC 110/WG 1 - Heat exchangers used in the field of refrigeration and air conditioning
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 05-Mar-2025
• Completion Date: 23-Sep-2025
• Ref Project: SIST EN 13487:2019 - Heat exchangers - Forced convection air cooled refrigerant condensers and dry coolers - Sound measurement

Relations

• Replaces: EN 13487:2003 - Heat exchangers - Forced convection air cooled refrigerant condensers and dry coolers - Sound measurement
• Effective Date: 08-Jun-2022

Overview

EN 13487:2019 - "Heat exchanger - Forced convection air cooled refrigerant condensers and dry coolers - Sound measurement" is a CEN standard that specifies objective methods to assess and present the acoustic emission characteristics of air‑cooled heat exchangers under stationary operating conditions. It applies to self‑standing forced convection air‑cooled refrigerant condensers, forced convection unit air coolers and air‑cooled liquid coolers (“dry coolers”).

This standard is intended to produce repeatable sound power levels (LW) and related acoustic data suitable for certification, labeling and product selection.

Key topics and requirements

• Scope and applicability: Covers forced‑convection air‑cooled condensers, unit air coolers and dry coolers; applies to equipment of various sizes with reference to EN ISO measurement limitations.
• Sound power determination: Procedures to determine A‑weighted sound power level (LWA), spectral sound power levels, and emission sound pressure level at workplace (LpA).
• Measurement methods: References and aligns with international acoustics methods such as EN ISO 3741 / 3743 / 3744 / 3745 / 3746 and EN ISO 9614 (sound intensity) for laboratory and engineering class measurements.
• Microphone positions & measurement surfaces: Guidance for free‑field over reflecting plane, hard‑walled or reverberant rooms and sound intensity scanning.
• Operating and installation conditions: Defines required recording of mounting, location, electrical supply and fan speed settings to ensure comparable results.
• Background noise & uncertainty: Procedures for evaluating background noise and calculating measurement uncertainties; annexes provide calculation and simplified measuring arrangements.
• Reporting & declaration: Lists minimum information to record and report (test environment, instrumentation, acoustical data) and guidance for declaration and verification of noise emission values.

Applications and who uses it

EN 13487:2019 is used by:

• Heat exchanger and HVAC manufacturers for product development, noise performance verification, labeling and compliance.
• Accredited test laboratories and acoustic test facilities performing sound power and sound pressure measurements.
• Acoustic consultants and engineers specifying acceptable noise levels for installations and designing mitigation.
• Specifiers, procurement teams and facility managers selecting condensers, dry coolers or unit coolers based on declared noise data.
• Certification bodies and regulators requiring standardized, low‑uncertainty acoustic data for marketing and regulatory compliance.

Related standards

• EN ISO 3741, EN ISO 3743‑1 / 3743‑2, EN ISO 3744, EN ISO 3745, EN ISO 3746 (sound pressure methods)
• EN ISO 9614‑1 / ‑2 / ‑3 (sound intensity methods)
• EN ISO 11203 and EN ISO 4871 (emission sound pressure and declaration)
• EN 327, EN 328, EN 1048 (product family specifications)

EN 13487:2019 provides a harmonized framework for reliable, comparable noise data for air‑cooled heat exchangers - essential for manufacturers, test labs and buyers focused on acoustic performance.

Standards Content (Sample)

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

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.

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
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

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.
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.
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
W
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 ;
WA
— spectral sound power levels;
— emission sound pressure level at workplace, L .
pA
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)
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
L
p
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:
p
L = 10lg dB
p
p
where the reference value, p , is 20 μPa.
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
L
W
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
P
L = 10lg dB
W
P
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.
WA
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]
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.
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.
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
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 chos
...