EN ISO 7235:2003
(Main)Acoustics - Laboratory measurement procedures for ducted silencers and air-terminal units - Insertion loss, flow noise and total pressure loss (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)
Diese Internationale Norm legt Verfahren zur Bestimmung der folgenden Größen fest:
- Einfügungsdämpfungsmaße von durchströmten und nicht durchströmten Kanalschalldämpfern in Frequenz-bändern;
- Schallleistungspegel des von Kanalschalldämpfern erzeugten Strömungsgeräusches in Frequenzbändern;
- Gesamtdruckverlust von durchströmten Schalldämpfern und
- Durchgangsdämpfungsmaße von Luftdurchlässen in Frequenzbändern.
Die Messverfahren sind zur Anwendung in einem Prüfstand bei Umgebungstemperatur vorgesehen. Vor-Ort-Messungen (Messungen im Einsatzfall) an Schalldämpfern werden durch ISO 11820 festgelegt.
Es ist anzumerken, dass die in einem Prüfstand erzielten Ergebnisse von Messungen nach dieser Internationalen Norm aufgrund von abweichenden Schall- und Strömungsfeldern nicht notwendigerweise mit denen von Vor-Ort-Messungen (Messungen im Einsatzfall) übereinstimmen. Zum Beispiel ist bei Laboratoriumsbedingungen der Druckverlust geringer als vor Ort, aber er ist vergleichbar groß zwischen verschiedenen Laboratorien.
Diese Internationale Norm gilt für alle Bauarten von Schalldämpfern einschließlich der Schalldämpfer für Lüftungs- und Luftkonditionierungsanlagen, Zuluftsysteme und Abgasanlagen und ähnliche Anwendungsfälle. Weitere passive luftführende Systeme, z. B. Krümmer, Luftdurchlässe und T-Stücke, können ebenfalls nach dieser Internationalen Norm gemessen werden.
Diese Internationale Norm gilt nicht für Reflexionsschalldämpfer (reaktiv wirkende Schalldämpfer), die in Kraftfahrzeugen zum Einsatz kommen.
ANMERKUNG 1 Anhang A beschreibt den Aufbau der Schallquelle zur Schallfeldanregung. Anhang B enthält Anforderungen an Übertragungselemente. In Anhang C sind Einzelheiten zu Kanalwänden und Grenzdämpfungsmaß angegeben. Anhang D enthält die Umrechnung von Dämpfungswerten in Terzbändern in solche in Oktavbändern. In Anhang E sind Messungen an großen Kulissenschalldämpfern beschrieben. In Anhang F ist die Prüfung der Längsdämpfung festgelegt. Anhang G gibt Hinweis
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)
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)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2004
1DGRPHãþD
SIST EN ISO 7235:1997
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 7235:2003
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 2003
ICS 91.120.20 Supersedes EN ISO 7235:1995
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 June 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7235:2003 E
worldwide for CEN national Members.
CORRECTED 2003-09-24
Foreword
This document (EN ISO 7235:2003) has been prepared by Technical Committee ISO/TC 43
"Acoustics" in collaboration with 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 2004, and conflicting national
standards shall be withdrawn at the latest by February 2004.
This document supersedes EN ISO 7235:1995.
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 EU
Directive(s).
For relationship with EU Directive(s), see informative annex ZB, which is an integral part 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, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
Endorsement notice
The text of ISO 7235:2003 has been approved by CEN as EN ISO 7235:2003 without any
modifications.
NOTE Normative references to International Standards are listed in Annex ZA (normative).
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of
any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications, indicated
by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 3741 1999 Acoustics - Determination of sound EN ISO 3741 1999
power levels of noise sources using
sound pressure - Precision methods
for reverberation rooms
ISO 3746 1995 Acoustics - Determination of sound EN ISO 3746 1995
power levels of noise sources using
sound pressure - Survey method using
an enveloping measurement surface
over a reflecting plane
ISO 9614-3 2002 Acoustics - Determination of sound EN ISO 9614-3 2002
power levels of noise sources using
sound intensity - Part 3: Precision
method for measurement by scanning
Annex ZB
(informative)
Relationship of this document with EC Directives
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 Directive(s) :
Machinery Directive 98/37/EC, amended by Directive 98/79/EC.
Compliance with this document provides one means of conforming with the specific essential
requirements of the Directive concerned and associated EFTA regulations.
WARNING: Other requirements and other EC Directives may be applicable to the product(s)
falling within the scope of this document.
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
Annex D (normative) Conversion of one-third-octave-band attenuation values to octave-band
attenuation values. 40
Annex E (normative) Measurements on large parallel-baffle silencers . 41
Annex F (normative) Test of longitudinal attenuation . 43
Annex G (informative) Anechoic terminations. 44
Annex H (informative) Examples of measurement arrangements. 46
Bibliography . 48
ISO 7235:2003(E)
Foreword
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