EN 24869-3:1993
(Main)Acoustics - Hearing protectors - Part 3: Simplified method for the measurement of insertion loss of ear-muff type protectors for quality inspection purposes (ISO/TR 4869-3:1989)
Acoustics - Hearing protectors - Part 3: Simplified method for the measurement of insertion loss of ear-muff type protectors for quality inspection purposes (ISO/TR 4869-3:1989)
The Technical Report specifies a method for measuring the insertion loss of ear-muff type hearing protectors for quality inspection purposes. The method may also be used to investigate production spreads of performance as part of type approval or certification procedures and to investigate the change of performance with age. A measurement of application force is specified because the force affects acoustic performance. The method specified in this Technical Report is not intended to be used as the basic test for type approval purposes. Performance data obtained by this method are not to be quoted as representing the real-ear sound attenuation of an ear-muff, nor the protection provided by the ear-muff. Note 1: A further application of the method is its use to ensure that ear-muff hearing protector samples submitted for subjective testing of attenuation according to ISO 4869-1 have performance typical of the type. Note 2: For the testing of certain ear-muffs such as those attached to safety helmets, or those with contoured ear-cups or ear-cushions, the procedure described in this Technical Report may have to be slightly modified.
Akustik - Gehörschützer - Teil 3: Vereinfachtes Verfahren zur Messung der Schalldämpfung von Kapselgehörschützern zum Zweck der Qualitätsprüfung (ISO/TR 4869-3:1989)
Dieser Fachbericht beschreibt ein Verfahren zur Messung der Schalldämmung von Kapselgehörschützern für Qualitätsprüfzwecke. Das Verfahren kann auch angewendet werden, um im Rahmen von Bauartzulassungen Produktionsstreuungen zu ermitteln und zeitliche Veränderungen von Eigenschaften zu untersuchen. Ausserdem wird eine Messung der Andrückkraft beschrieben, denn die Andrückkraft beeinflusst die Schalldämmungseigenschaften.
Acoustique - Protecteurs individuels contre le bruit - Partie 3: Méthode simplifiée pour le mesurage de l'affaiblissement acoustique du type serre-tête, destinée aux contrôles de qualité (ISO/TR 4869-3:1989)
Akustika – Oprema za varovanje sluha - 3. del: Poenostavljena metoda za merjenje dušenja naušnikov za namene nadzora kakovosti (ISO/TR 4869-3:1989)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 24869-3:1999
01-november-1999
Akustika – Oprema za varovanje sluha - 3. del: Poenostavljena metoda za merjenje
dušenja naušnikov za namene nadzora kakovosti (ISO/TR 4869-3:1989)
Acoustics - Hearing protectors - Part 3: Simplified method for the measurement of
insertion loss of ear-muff type protectors for quality inspection purposes (ISO/TR 4869-
3:1989)
Akustik - Gehörschützer - Teil 3: Vereinfachtes Verfahren zur Messung der
Schalldämpfung von Kapselgehörschützern zum Zweck der Qualitätsprüfung (ISO/TR
4869-3:1989)
Acoustique - Protecteurs individuels contre le bruit - Partie 3: Méthode simplifiée pour le
mesurage de l'affaiblissement acoustique du type serre-tete, destinée aux contrôles de
qualité (ISO/TR 4869-3:1989)
Ta slovenski standard je istoveten z: EN 24869-3:1993
ICS:
13.340.20 Varovalna oprema za glavo Head protective equipment
SIST EN 24869-3:1999 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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TECHNICAL
ISO
REPORT TR 4869-3
First edition
1989-11-15
- Hearing protectors -
Acoustics
Part 3:
Simplified method for the measurement of insertion
loss of ear-muff type protectors for quality inspection
purposes
Acoustique - Pro tecteurs individuels contre Ie bruit -
Partie 3: Mbthode simplif/ee de mesurage de l’affaiblissement acoustique des
protecteurs du type serre- t&te, destinee aux contr6les de qualit6
Reference number
ISO/TR 4869-3 : 1989 (EI
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ISO/TR 4869-3 : 1989 (E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of
national Standards bodies (ISO member bedies). The work of preparing International
Standards is normally carried out through ISO technical committees. Esch member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
The main task of ISO technical committees is to prepare International Standards. In
exceptional circumstances a technical committee may propose the publication of a
technical report of one of the following types :
1, when the necessary support within the technical committee cannot be
- tYPe
obtained for the publication of an International Standard, despite repeated efforts;
-
development
type 2, when the su bject is still under technical requiring wider
exposure;
-
type 3, when a technical committee has collected data of a different kind from
that which is normally published as an International Standard (“state of the art”, for
example).
Technical reports are accepted for publication directly by ISO Council. Technical
reports types 1 and 2 are subject to review within three years of publication, to decide
whether they tan be transformed into International Standards. Technical reports
type 3 do not necessarily have to be reviewed until the data they provide are
considered to be no longer valid or useful.
ISO/TR 4869-3, which is a technical report of type 2, was prepared by Technical
Committee ISO/TC 43, Acoustics.
ISO 4869 will consist of the following Parts, under the general title Acoustics -
Hearing pro tectors :
-
Part 7: Subjective method for the measurement of Sound attenuation
-
Part 2: Estimated noise reduction
-
Part 3: Simpfified method for the measurement of insertion Ioss of
ear-mu ff
protectors for quality inspection purposes [Technical Report]
Annex A of this Technical Report is for information only.
@ ISO 1989
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronie or mechanical, including photocopying and microfilm, without Permission in
writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
ii
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ISO/TR 4869-3 : 1989 (El
Introduction
During the preparation of ISO 4869 : 1981, Acoustics - Measurement of Sound at-
tenuation of hearing pro tectors - Subjective method, the document contained at a
certain time both a subjective and a purely physical measurement method. Based on
member body comments it was decided to Split up the two methods in separate
documents, giving priority to the subjective method which was issued in 1981 as
ISO 4869. A first draft proposal for the physical method, document 43/1 N 367, was
circulated to ISO/TC 43/SC 1 member bodies for comments in the period 1978-12-15
to 1979-03-15 for presentation at the SC 1 meeting in May 1979 in Stockholm,
Sweden, where a second draft proposal, document 43/1 N 390, was approved for
DIS-circulation subject to amendments in response to comments made at the meeting.
ISO/DIS 6290 was circulated for voting amongst all ISO member bodies in the period
1983-01-06 to 1983-07-06. Upon recommendation from Working Group 17, the plenary
SC 1 meeeting in April 1985 in Budapest, Hungary, approved that an amended text be
submitted to ISO/TC 43 member bodies for adoption as a technical report. Such a pro-
posal for a technical report was circulated for voting amongst ISO/TC 43 member
bodies as document 43 N 749 in the period 1986-12-15 to 1987-01-20 with the following
result: 12 approvals, 1 disapproval and 1 abstention.
A subjective method for the measurement of the Sound attenuation of hearing protec-
tors is given in ISO 4869-1. In Order to describe a simplified method for the measurement
of the insertion loss using an objective method for production control and certification
applications, an acoustic test fixture as specified in this Technical Report has been
developed with the aim of achieving a simple but reproducible method of measurement.
The acoustic test fixture was tested in a round robin test including hearing protectors
of the ear-muff type tested at some laboratories (Germany, F.R., Sweden, UK). The
results were encouraging.
ependent international round robin
The new testing method has been used in two ind
tests within the EEC and in the Nordic countries.
The reproducibility of the results from these tests is, however, not satisfactory. The
major reasons for the deviations observed cannot be fully explained at present. There is
a need for further experiments with the acoustic test fixture in Order to clarify the
reasons for the deviations in the results.
In Order to allow gathering of data and experience with this device to provide a
background for resolving the present Problems and for issuing an International Stan-
dard within a few years, it has been decided to publish a description of the test fixture
and of the measurement procedure presented in ISO/DIS 6290 - revised in response
in the form of a technical report,
to comments submitted during the DIS-voting -
under number ISO/TR 4869-3.
The method specified in this Technical Report does not provide results which are the
same as those obtained by the subjective method because of the requirements for
simplicity and reproducibility of test results and other more basic considerations.
The test fixture specified in this Technical Report is not intended to supplant those
dummy heads which include Simulation of various anatomical features and which are
used, for example, for development testing purposes.
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TECHNICAL REPORT
ISO/TR 4869-3 : 1989 (E)
Acoustics - Hearing protectors -
Part 3:
Simplified method for the measurement of insertion loss of
ear-muff type protectors for quality inspection purposes
1 Scope ISO 4869-1 : - 11, Acoustics - Hearing protectors - Part 7:
Subjective method for the measurement of Sound attenuation.
This Technical Report specifies a method for measuring the
IEC 225 : 1966, Octave, half-octave and third-octave band
insertion loss of ear-muff type hearing protectors for quality
filters in tended for the analysis of Sound and vibrations.
inspection purposes. The method may also be used to in-
vestigate production spreads of Performance as part of type
IEC 263 : 1982, Scales and sizes for plotting frequency
approval or cet-tification procedures and to investigate the
charac teris tics.
Change of Performance with age.
IEC 50(801) : 1984, International Electrotechnical Vocabulary.
A measurement of application forte is specified because the
Chapter 807: Acoustics and electro-acoustics. Section 7:
forte affects acoustic Performance.
General terms.
The method specified in this Technical Report is not intended
to be used as the basic test for type approval purposes. Per-
3 Definitions
formance data obtained by this method are not to be quoted as
representing the real-ear Sound attenuation of an ear-muff, nor
For the purposes of this Technical Report, the following defi-
the protection provided by the ear-muff.
nitions apply.
NOTES
3.1 hearing protector : A device worn by a person to pre-
vent unwanted auditory effects from acoustic Stimuli.
1 A further application of the method is its use to ensure that ear-
muff hearing protector samples submitted for subjective testing of
attenuation according to ISO 4869-1 have Performance typical of the
3.2 ear-muff: A hearing protector consisting of an ear-cup
tYPe.
to be pressed against each pinna or of a circumaural ear-cup to
be pressed against the head around the pinna. The ear-cups
2 For the testing of cet-tain ear-muffs such as those attached to safety
tan be pressed against the head with a special headband or
helmets, or those with contoured ear-cups or ear-cushions, the pro-
cedure described in this Technical Report may have to be slightly
neck-band or by means of a device attached to a safety helmet
modified.
or other equipment.
3.3 headstrap: A flexible strap fitted to each CUP, or to the
headband close to the CUP. lt may be adjusted to support the
2 Normative references
ear-muffs, usually behind-the-head types, by resting on the top
of the head.
The following Standards contain provisions which, through
reference in this text, constitute provisions of this Technical
3.4 acoustic test fixture: A device that approximates cer-
Report. At the time of publication, the editions indicated were
tain dimensions of an average adult human head and is used,
valid. All Standards are subject to revision, and Parties to
for the purposes of this Technical Report, for measuring the
agreements based on this Technical Report are encouraged to
insertion loss of hearing protectors of ear-muff type. For this
investigate the possibility of applying the most recent editions
purpose, it includes a microphone arrangement for measuring
of the Standards indicated below. Members of IEC and ISO
Sound pressure levels.
maintain registers of currently valid International Standards.
ISO 48 : 1979, Vulcanized rubbers - Determination of hard- insertion loss: The algebraic differente, in decibels,
35
ness (Hardness betvveen 30 and 85 IRHDI. between the one-third octave band pressure level measured by
1) To be published. (Revision of ISO 4869 : 1981.)
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ISO/TR 4869-3 : 1989 (El
b) a fixed capillary tube connecting the cavity under the ear-muff
the microphone of the acoustic test fixture in a specified Sound
to the external air. The tube should be of diameter 0,5 mm, of
field under specified conditions with the hearing protector
length 25 mm, parallel with and near to the axis of the microphone
absent and the Sound pressure level with the hearing protector
of the acoustic test fixture, partly closed by a wire of diameter
on with other conditions identical.
0,4 mm and combined with a tube of diameter about 3 mm from
the bottom of the cylinder perpendicular to the microphone axis.
3.6 pink noise : Noise the power spectral density of which is
inversely proportional to frequency, i.e. equal energy in each
51.2 A spacer shall project from the centre of the length of
one-third octave band [see IEC 50 (80111.
the cylinder and at right angles to the centre axis of the cylinder
to support the centre of the headband of the ear-muff under
37 . noise floor: The output level of the measurement
test. The spacer shall be of length (123 & 1) mm from the
microphone with the test Signal switched off and the acoustic
centre axis of the cylinder. The free end of the spacer shall have
isolation test cup in Position (see 5.1).
a cylindrical radius of (100 + 1) mm. A rubber pad (6 + 1) mm
thick and of hardness within the range 30 IRHD to 85 IRHD
g the
3.8 reference Point : The midpoint of a line connectin
(see ISO 48) shall be attached to the end of the spacer to pro-
centres of the two end faces of the acoustic test fixture.
vide a slightly resilient seating for the ear-muff headband. The
free face of the rubber pad shall be (50 + 1) mm wide and
(77 + 1) mm long.
4 Principle
An example of a suitable test fixture is shown in figure 1.
The level of a test Signal in a defined Sound field is measured by
a microphone located in a test fixture with and without the
5.1.3 The acoustic isolation of the test fixture shall be at least
microphone being occluded by the ear-muffs under test.
50 dB for centre frequencies 63 Hz to 250 Hz, at least 65 dB for
centre frequencies between 315 Hz and 4 kHz and at least
55 dB for higher test centre frequencies at the actual test site,
of ear
5 Measurement of the insertion
measured with the test Signal described in 5.2 and with the
muffs
microphone covered by the acoustic isolation test cup shown in
figure 1. The isolation test cup shall be sealed to the acoustic
5.1 Acoustic test fixture test fixture.
NOTE - The acoustic isolation test cup may be attached to the test
5.1.1 The acoustic test f
...
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