00374187 PDF BRITISH STANDARD BS EN 24869 1 1993 ISO 4869 1 1990 Incorporating Amendment No 1 Sound attenuation of hearing protectors — Part 1 Subjective method of measurement The European Standard EN[.]
BRITISH STANDARD BS EN 24869-1:1993 ISO 4869-1: 1990 Incorporating Amendment No Sound attenuation of hearing protectors — Part 1: Subjective method of measurement The European Standard EN 24869-1:1992 has the status of a British Standard UDC 614.892:620.1:534.61:534.833.5 BS EN 24869-1:1993 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical Committee EPC/1, upon which the following bodies were represented: Association of Consulting Engineers British Broadcasting Corporation British Occupational Hygiene Society British Telecommunications plc Department of Health Department of the Environment (Building Research Establishment) Department of Trade and Industry (Air Division) Department of Trade and Industry (National Physical Laboratory) Engineering Equipment and Materials Users’ Association Health and Safety Executive Incorporated Association of Architects and Surveyors Institute of Acoustics Institute of Occupational Hygienists Institute of Physics Institute of Sound and Vibration Research Institution of Civil Engineers Institution of Electrical Engineers Royal Institute of British Architects Society of Environmental Engineers Transmission and Distribution Association (BEAMA Ltd.) The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Electricity Supply Industry in UK Industrial Safety (Protective Equipment) Manufacturers’ Association Institution of Mechancial Engineers Ministry of Defence Society of Hearing Aid Audiologists Ltd University of Salford This British Standard, having been prepared under the direction of the Environment and Pollution Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 28 June 1991 © BSI 08-1999 First published July 1974 Second edition September 1983 Third edition June 1991 Amendments issued since publication Amd No Date The following BSI references relate to the work on this standard: Committee reference EPC/1 Draft announced in BSI News July 1989 7552 February 1993 Indicated by a sideline in the margin ISBN 580 19628 Comments BS EN 24869-1:1993 Contents Page Committees responsible Inside front cover National foreword ii Foreword Scope Normative references 3 Definitions Measurement of the sound attenuation of hearing protectors Annex A (informative) Uncertainty of sound attenuation measurements Annex B (informative) Bibliography Table — Allowable field variation for different microphones Table — Maximum permissible background sound pressure level Table — Minimum and maximum sound pressure levels for test signals Table A.1 — Repeatability and reproducibility of sound attenuation measurements on ear-muffs at a probability level of 95 % (according to ISO 5725) Table A.2 — Repeatability and reproducibility of sound attenuation measurements on ear-plugs at a probability level of 95 % (according to ISO 5725) Publication(s) referred to Inside back cover © BSI 08-1999 i BS EN 24869-1:1993 National foreword This Part of BS 5108 has been prepared under the direction of the Environment and Pollution Standards Policy Committee It is identical with ISO 4869-1:1990 “Acoustics — Hearing protectors — Part 1: Subjective method for the measurement of sound attenuation”, published by the International Organization for Standardization (ISO) ISO 4869-1 was prepared by Subcommittee 1, Noise, of ISO Technical Committee 43, Acoustics, with the active participation and approval of the UK It constitutes a minor revision of ISO 4869:1981 In 1992 the European Committee for Standardization (CEN) accepted ISO 4869-1:1990 as European Standard EN 24869-1:1992 As a consequence of implementing the European Standard this British Standard is renumbered as BS EN 24869-1 and any reference to BS 5108-1:1991 should be read as a reference to BS EN 24869-1 This Part of BS 5108 is a revision of BS 5108:1983, which is withdrawn Further revised Parts of BS 5108 are in preparation A second Part will be based on ISO 4869-2 “Estimated noise reduction of hearing protectors” and a third Part is envisaged, based on a future revision of ISO/TR 4869-3:1989 “Simplified method for the measurement of insertion loss of ear-muff type protectors for quality inspection purposes” which was implemented, dual-numbered as DD 192:1990 Hearing protectors are commonly used to reduce the noise to which the ear is exposed Hearing protectors are manufactured as ear-plugs, ear-muffs or helmets A standardized method of sound attenuation measurement allows performance data obtained in different locations under similar conditions to be compared The data may be used for rank ordering and selection of different models and the evaluation of design and construction features that affect performance Cross-references ii International Standard Corresponding British Standard ISO 354:1985 BS 3638:1987 Method for measurement of sound absorption in a reverberation room (Identical) ISO 389:1985 BS 2497 Standard reference zero for the calibration of pure tone air conduction audiometers Part 5:1988 Specification for a standard reference zero using an acoustic coupler complying with BS 4688 (Identical) ISO 5725:1986 BS 5497 Precision of test methods Part 1:1987 Guide for the determination of repeatibility and reproducibility for a standard test method by inter-laboratory tests (Identical) ISO 6189:1983 BS 6655:1986 Specification for pure tone air conduction threshold audiometry for hearing conservation purposes (Identical) IEC 225:1966 BS 2475:1964 Specification for octave and one-third octave band-pass filters (Technically equivalent) IEC 263:1982 BS 6397:1983 Specification for scales and sizes for plotting frequency characteristics and polar diagrams (Identical) © BSI 08-1999 BS EN 24869-1:1993 International Standard Corresponding British Standard IEC 651:1979 BS 5969:1981 Specification for sound level meters (Identical) IEC 804:1985 BS 6698:1986 Specification for integrating-averaging sound level meters (Identical) The Technical Committee has reviewed the provisions of ISO 8253-2, to which reference is made in clause and 4.5.5 and in a note to 3.7, and of the draft of IEC 645-1, to which reference is made in clause and 4.3.4, and has decided that they are acceptable for use in conjunction with this standard ISO 8253-1, to which reference is made in a note to 3.6 and in the informative bibliography, is given for information only and does not affect the use of this Part of BS 5108 A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application Compliance with a British Standard does not of itself confer immunity from legal obligations Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, the EN title page, pages to 8, an inside back cover and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover © BSI 08-1999 iii iv blank EUROPEAN STANDARD EN 24869-1 NORME EUROPÉENNE October 1992 EUROPÄISCHE NORM UDC 614.892:620.1:534.61:534.833.5 Descriptors: Acoustics, ear protectors, acoustic measurement, noise reduction English version Acoustics — Hearing protectors — Subjective method for the measurement of sound attenuation (ISO 4869-1:1990) Acoustique — Protecteurs individuels contre le bruit — Méthode subjective de mesurage de l’affaiblissement acoustique (ISO 4869-1:1990) Akustik — Gehörschützer — Subjektive Methode zur Messung der Schalldämmung (ISO 4869-1:1990) This European Standard was approved by CEN on 1992-10-16 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 Central Secretariat 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 Central Secretariat has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © 1992 Copyright reserved to CEN members Ref No EN 24869-1:1992 E EN 24869-1:1992 Foreword This European Standard is the endorsement of ISO 4869-1 Endorsement of ISO 4869-1 was recommended by Technical Committee CEN/TC 211 “Acoustics” under whose competence this European Standard will henceforth fall 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 April 1993, and conflicting national standards shall be withdrawn at the latest by April 1993 The Standard was approved and in accordance with the CEN/CENELEC Internal Regulations the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom © BSI 08-1999 EN 24869-1:1992 Scope This International Standard specifies a subjective method for measuring sound attenuation of hearing protectors at the threshold of hearing The method and procedures are designed to yield values close to the maximum attenuation which are not normally attained under field conditions This approach has been adopted because the attenuation values can then be consistently reproduced The values reflect the attenuating characteristics of the hearing protector only to the extent that users wear the device in the same manner as did the test subjects This test method yields data which are collected at low sound pressure levels (close to the threshold of hearing) but which are also representative of the attenuation values of hearing protectors at higher sound pressure levels An exception occurs in the case of amplitude-sensitive hearing protectors for sound pressure levels above the point at which their level-dependent characteristics become effective At those sound pressure levels the method specified in this International Standard is inapplicable; it will usually underestimate sound attenuation for these devices NOTE At low frequencies (below 500 Hz) the sound attenuation may be overestimated by a few decibels as a result of masking the occluded ear thresholds caused by physiological noise during the occluded ear tests Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 4869 At the time of publication, the editions indicated were valid All standards are subject to revision, and parties to agreements based on this part of ISO 4869 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below Members of IEC and ISO maintain registers of currently valid International Standards ISO 354:1985, Acoustics — Measurement of sound absorption in a reverberation room ISO 8253-2:—, Acoustics — Audiometric test methods — Part 2: Sound field audiometry with pure tone and narrow-band test signals1) IEC 225:1966, Octave, half-octave and third-octave band filters intended for the analysis of sounds and vibrations IEC 263:1982, Scales and sizes for plotting frequency characteristics and polar diagrams IEC 645-1:—, Audiometers — Part 1: Pure tone audiometers2) IEC 651:1979, Sound level meters 1) To 2) To IEC 804:1985, Integrating-averaging sound level meters Definitions For the purposes of this part of ISO 4869, the following definitions apply 3.1 hearing protector a device worn by a person to prevent unwanted auditory effects from acoustic stimuli NOTE Hearing protectors may include electronic devices for communication or devices designed to play an active role in the reduction of the noise level between the hearing protector and the ear-drum 3.2 ear-muff a hearing protector consisting of an ear-cup to be pressed against each pinna or of a circumaural ear-cup to be pressed against the head around the pinna The ear-cups can be pressed against the head with a special headband or neck-band or by means of a device attached to a safety helmet or other equipment 3.3 ear-plug a hearing protector worn within the external ear canal (aural) or in the concha against the entrance to the external ear canal (semi-aural) 3.4 helmet a device which covers a substantial part of the head 3.5 hearing level (of a pure tone) at a specified frequency, for a specified type of earphone and for a specified manner of application, the sound pressure level of this pure tone produced by the earphone in a specified acoustic coupler or artificial ear minus the appropriate reference equivalent threshold sound pressure level NOTE Values of reference equivalent threshold sound pressure levels are specified in ISO 389 3.6 hearing threshold level (of a given ear) at a specified frequency and for a specified type of earphone, the threshold of hearing expressed as hearing level NOTE For appropriate test conditions see, for example, ISO 6189 and ISO 8253-1 be published be published (Revision of IEC 645:1979.) © BSI 08-1999 EN 24869-1:1992 3.7 threshold of hearing Measurement of the sound attenuation of hearing protectors the lowest sound pressure level at which, under specified conditions, a person gives a predetermined percentage of correct detection responses on repeated trials 4.1 Test signals NOTE For the purpose of this International Standard, the threshold of hearing is measured with and without the hearing protector For appropriate test conditions, see ISO 8253-2 3.8 sound attenuation for a given test signal, the difference, in decibels, between the threshold of hearing with and without the hearing protector in place for a test subject The test signals shall consist of a signal from pink noise filtered through one-third octave bands with centre frequencies in accordance with IEC 225 Tests shall be performed at the following centre frequencies: 63 Hz (optional) 125 Hz 250 Hz 500 Hz 3.9 pink noise 000 Hz noise the sound pressure spectral density of which is inversely proportional to frequency 000 Hz 3.10 reference point the midpoint of a line connecting the test subject’s ear canal openings 3.11 reverberation time the time required for the sound pressure level to decrease by 60 dB after the sound source has stopped (see ISO 354) 3.12 repeatability the value below which the absolute difference between two single test results obtained with the same method on identical test material, under the same conditions (same operator, same apparatus, same laboratory, and a shod interval of time), may be expected to lie with a specified probability; in the absence of other indications, the probability is 95 % 3.13 reproducibility the value below which the absolute difference between two single test results obtained with the same method on identical test material, under different conditions (different operators, different apparatus, different laboratories and/or different time), may be expected to lie with a specified probability; in the absence of other indications, the probability is 95 % 000 Hz 000 Hz 4.2 Test site 4.2.1 Diffuse sound field conditions are required and are adequately approximated when the following requirements are met: a) With the test subject and the subject’s chair absent, the sound pressure level measured with an omnidirectional microphone at positions 15 cm from the reference point on the front-back, right-left and up-down axes shall deviate by no more than ± 2,5 dB from the sound pressure level at the reference point for any of the test signals Further, the difference between the extreme right-left positions shall not exceed dB The orientation of the microphone shall be kept the same at each position b) At frequencies of 500 Hz and above, the sound pressure level at the reference point shall be within dB for the two directions of measurement that give maximum and minimum readings of the incident sound energy when measured with a directional microphone with a front-to-random sensitivity index of dB For other directional microphones the relationship between front-to-random sensitivity index and the allowable field variation is given in Table © BSI 08-1999 EN 24869-1:1992 Table — Maximum permissible background sound pressure level Table — Allowable field variation for different microphones Front-to-random sensitivity index Allowable field variation dB dB W5 4,5 4,5 4 000 Hz Repeatability (for 2,5 measurements under identical test conditions) 2,5 Reproducibility for 2,5 test group variations (but otherwise identical test conditions) 3,5 Reproducibility (for measurements in different laboratories) 6,5 Table A.2 — Repeatability and reproducibility of sound attenuation measurements on ear-plugs at a probability level of 95 % (according to ISO 5725) Values in decibels Test centre frequency < 250 Hz 250 Hz to 000 Hz > 000 Hz 3,5 Repeatability (for measurements under identical test conditions) 2,5 3,5 Reproducibility for test group variations (but otherwise identical test conditions) 4 Reproducibility (for measurements in different laboratories) 6,5 6,5 Annex B (informative) Bibliography [1] ISO 389:1985, Acoustics — Standard reference zero for the calibration of pure tone air conduction audiometers [2] ISO 5725:1986, Precision of test methods — Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests [3] ISO 6189:1983, Acoustics — Pure tone air conduction threshold audiometry for hearing conservation purposes [4] ISO 8253-1:1989, Acoustics — Audiometric test methods — Part 1: Basic pure tone air and bone conduction threshold audiometry [5] BRINKMANN, K and RICHTER, U Repeatability and reproducibility of sound attenuation measurements on hearing protectors according to ISO 4869 Internal Report Physikalisch-Technische Bundesanstalt, Braunschweig, Germany, F.R., 1988 [6] POULSEN, T Nordic round robin test in hearing protector measurements, Vol I, Internal Report No 21 The Acoustics Laboratory, Technical University of Denmark, 1984 [7] SHIPTON, M.S Intercomparison of measurements on ear protectors by subjective and objective test methods Final report on the 1982 EEC intercomparison EUR 10575 E.N Luxembourg, Office for Official Publications of the European Communities, 1986 © BSI 08-1999 BS EN 24869-1:1993 Publication(s) referred to See national foreword © BSI 08-1999 BS EN 24869-1:1993 ISO 4869-1: 1990 BSI — British Standards Institution BSI is the independent national body responsible for preparing British Standards It presents the UK view on 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