EN ISO 7235:2009

SLOVENSKI STANDARD
01-november-2009
1DGRPHãþD
SIST EN ISO 7235:2004
Akustika - Laboratorijski merilni postopki za dušilnike v kanalih in elementih za
dovod in odvod zraka - Dodano dušenje, hrup zaradi pretoka in padec celotnega
tlaka (ISO 7235:2003)
Acoustics - Laboratory measurement procedures for ducted silencers and air-terminal
units - Insertion loss, flow noise and total pressure loss (ISO 7235:2003)
Akustik - Labormessungen an Schalldämpfern in Kanälen - Einfügungsdämpfung,
Strömungsgeräusch und Gesamtdruckverlust (ISO 7235:2003)
Acoustique - Modes opératoires de mesure en laboratoire pour silencieux en conduit et
unités terminales - Perte d'insertion, bruit d'écoulement et perte de pression totale (ISO
7235:2003)
Ta slovenski standard je istoveten z: EN ISO 7235:2009
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
91.120.20 $NXVWLNDYVWDYEDK=YRþQD Acoustics in building. Sound
L]RODFLMD insulation
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 7235
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 91.120.20 Supersedes EN ISO 7235:2003
English Version
Acoustics - Laboratory measurement procedures for ducted
silencers and air-terminal units - Insertion loss, flow noise and
total pressure loss (ISO 7235:2003)
Acoustique - Modes opératoires de mesure en laboratoire Akustik - Labormessungen an Schalldämpfern in Kanälen -
pour silencieux en conduit et unités terminales - Perte Einfügungsdämpfung, Strömungsgeräusch und
d'insertion, bruit d'écoulement et perte de pression totale Gesamtdruckverlust (ISO 7235:2003)
(ISO 7235:2003)
This European Standard was approved by CEN on 20 July 2009.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7235:2009: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/EC .4
Annex ZB (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC .5

Foreword
The text of ISO 7235:2003 has been prepared by Technical Committee ISO/TC 43 “Acoustics” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 7235:2009 by
Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by DS.
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 2010, and conflicting national standards shall be withdrawn
at the latest by February 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 7235:2003.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EC Directives.
For relationship with EC Directives, see informative Annexes ZA and ZB, which are integral parts of this
document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 7235:2003 has been approved by CEN as a EN ISO 7235:2009 without any modification.
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/EC
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide a means of conforming to Essential Requirements of the
New Approach Directive 98/37/EC, amended by 98/79/EC on machinery.
Once this standard is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the normative
clauses of this standard confers, within the limits of the scope of this standard, a presumption of conformity
with the relevant Essential Requirements of that Directive and associated EFTA regulations.
WARNING - Other requirements and other EU Directives may be applicable to the product(s) falling within the
scope of this standard.
Annex ZB
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide a means of conforming to Essential Requirements of the
New Approach Directive 2006/42/EC on machinery.
Once this standard is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the normative
clauses of this standard confers, within the limits of the scope of this standard, a presumption of conformity
with the relevant Essential Requirements of that Directive and associated EFTA regulations.
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within
the scope of this standard.
INTERNATIONAL ISO
STANDARD 7235
Second edition
2003-08-01
Acoustics — Laboratory measurement
procedures for ducted silencers
and air-terminal units — Insertion loss,
flow noise and total pressure loss
Acoustique — Modes opératoires de mesure en laboratoire pour
silencieux en conduit et unités terminales — Perte d'insertion, bruit
d'écoulement et perte de pression totale

Reference number
ISO 7235:2003(E)
©
ISO 2003
ISO 7235:2003(E)
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ISO 7235:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols . 7
5 Test facilities and requirements for instrumentation. 9
5.1 Purpose and types of test facilities. 9
5.2 Equipment for acoustic testing of silencers . 9
5.3 Equipment for acoustic testing of air-terminal units . 15
5.4 Equipment for flow testing. 16
5.5 Equipment for dynamic testing . 21
6 Test procedures . 22
6.1 General. 22
6.2 Insertion loss. 22
6.3 Transmission loss. 24
6.4 Sound power level of the flow noise (or regenerated sound) . 24
6.5 Volume flow rate and pressure loss coefficient . 25
7 Information to be recorded . 29
7.1 Description of the test object . 29
7.2 Instrumentation . 29
7.3 Sound-source equipment. 30
7.4 Test, substitution and transmission ducts.30
7.5 Transitions. 30
7.6 Anechoic termination . 30
7.7 Reverberation room . 30
7.8 Acoustical test results. 30
7.9 Measurement uncertainty. 31
8 Information to be reported . 31
Annex A (normative) Design of the sound field excitation equipment and qualification tests . 32
Annex B (normative) Transmission element. 34
Annex C (normative) Duct walls and limiting insertion loss . 37
...