DD-ISO-TS-4869-5-2006.pdf

DRAFT FOR DEVELOPMENT DD ISO/TS 4869-5:2006 Acoustics Hearing protectors Part 5: Method for estimation of noise reduction using fitting by inexperienced test subjects ICS 13.340.20 ? Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI DD ISO/TS 4869-5:2006 This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 29 December 2006 © BSI 2006 ISBN 0 580 49881 6 National foreword This Draft for Development was published by BSI. It is the UK implementation of ISO/TS 4869-5:2006. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature. It should be applied on this provisional basis, so that information and experience of its practical application can be obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the international organization responsible for its conversion to an international standard. A review of this publication will be initiated not later than 3 years after its publication by the international organization so that a decision can be taken on its status. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into an international Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent to the Secretary of the responsible BSI Technical Committee at British Standards House, 389 Chiswick High Road, London W4 4AL. The UK participation in its preparation was entrusted by Technical Committee EH/1, Acoustics, to Subcommittee EH/1/1, Hearing. A list of organizations represented on EH/1/1 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Reference number ISO/TS 4869-5:2006(E) TECHNICAL SPECIFICATION ISO/TS 4869-5 First edition 2006-10-15 Acoustics Hearing protectors Part 5: Method for estimation of noise reduction using fitting by inexperienced test subjects Acoustique Protecteurs individuels contre le bruit Partie 5: Méthode d'estimation de la réduction du bruit au moyen de réglages par des sujets d'essai non expérimentés DD ISO/TS 4869-5:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iii Contents Page Foreword. v Introduction vii 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 2 4 Measurement of the noise reduction of hearing protectors 3 4.1 Test signals . 3 4.2 Test site . 3 4.2.1 Conditions to be met for the test to be valid . 3 4.2.2 Reverberation time . 4 4.2.3 Background noise. 4 4.3 Test equipment . 5 5 Test subjects. 6 5.1 Conditions for subject acceptance/dismissal . 6 5.1.1 General. 6 5.1.2 Age and sex. 6 5.1.3 Previous experience with hearing protectors 7 5.1.4 Anatomical features 7 5.1.5 Maximum hearing threshold levels. 7 5.1.6 Minimum hearing threshold levels 7 5.1.7 Literacy 7 5.1.8 Threshold variability. 7 5.2 Number of subjects 7 5.3 Otoscopic inspection . 8 5.4 Spectacles and jewellery . 8 5.5 Maximum number of tests per subject. 8 5.6 Exceptions. 8 6 Product samples. 8 6.1 General. 8 6.2 Custom-moulded ear-plugs. 8 6.3 Special requirements for product instruction . 8 6.4 Variable position headbands. 9 6.5 Variable band force. 9 7 Test procedure 9 7.1 Number of open-ear and occluded-ear threshold measurements. 9 7.2 Information to subjects 9 7.3 Prior to entering the test room 10 7.4 Inside the test room 10 7.4.1 Positioning the subject 10 7.4.2 Quiet period prior to first threshold determination. 11 7.4.3 Fitting the hearing protector for test 11 7.4.4 Re-determination of thresholds 11 8 Computation of noise reduction values. 12 8.1 General. 12 8.2 Calculation of the individual noise reductions 12 8.3 Calculation of group noise reduction. 12 8.4 Uncertainty of the noise reduction data. 13 DD ISO/TS 4869-5:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv 9 Reporting of data 13 Annex A (informative) Uncertainty of hearing protector noise reduction measurements15 Bibliography .18 DD ISO/TS 4869-5:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI v Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each 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, governmental 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International Standard or be withdrawn. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TS 4869-5 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise. ISO/TS 4869 consists of the following parts, under the general title Acoustics Hearing protectors: Part 1: Subjective method for the measurement of sound attenuation Part 2: Estimation of effective A-weighted sound pressure levels when hearing protectors are worn Part 3 1): Measurement of insertion loss of ear-muff type protectors using an acoustic test fixture Part 4: Measurement of effective sound pressure levels for level-dependent sound-restoration ear-muffs (ISO/TR) Part 5: Method for estimation of noise reduction using fitting by inexperienced test subjects (ISO/TS) 1) To be published. DD ISO/TS 4869-5:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI vi The following part is under development: Part 6: Active noise reduction of hearing protectors 2) Annex A of this part of ISO 4869 is for information only. 2) Presently a preliminary work item. DD ISO/TS 4869-5:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI vii Introduction Hearing protectors are used to reduce the noise to which the ear is exposed. Hearing protectors are generally divided into ear-muffs and ear-plugs with a great variety of products within both categories. The measurement conditions given in this Technical Specification making use of inexperienced hearing protector users is believed to provide results that are representative for the noise reduction obtained by groups of typical users in real-world occupational settings. The method described in ISO 4869-1 yields the sound attenuation of the hearing protector under test. The result of the measurement is a pure physical characteristic of the hearing protector. The method described in this Technical Specification yields the performance of the system as a whole, i.e. hearing protector, test subjects, fitting and instruction. DD ISO/TS 4869-5:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 1 Acoustics Hearing protectors Part 5: Method for estimation of noise reduction using fitting by inexperienced test subjects 1 Scope This Technical Specification specifies a method for measuring noise reduction of passive hearing protectors at the threshold of hearing. The method is designed to provide estimates of the noise reduction obtained by typical groups of users in real-world occupational settings, who may lack the training and motivation to wear hearing protectors in an optimum manner. The principle of the test method is to measure the difference in hearing threshold with and without wearing a hearing protector. This difference between the thresholds constitutes the noise reduction. The measurement is done twice on a given number of test subjects. NOTE 1 The principle of measuring the influence of a hearing protector on the hearing threshold is used in ISO 4869-1 and in this Technical Specification. The method described in ISO 4869-1 yields the sound attenuation of the hearing protector under test. The result of the measurement is a pure physical characteristic of the hearing protector. The method described in this Technical Specification yields the performance of the system as a whole, i.e. the influence of hearing protector, test subjects, fitting and instruction. This test method yields data that are collected at low sound pressure levels (close to the threshold of hearing), but which are also representative of the noise reduction values of hearing protectors at higher sound pressure levels. This Technical Specification is inapplicable for level-dependent hearing protectors for sound pressure levels above the point at which their level-dependent characteristics become effective. NOTE 2 At frequencies below 500 Hz, real-ear noise reduction data measured according to this Technical Specification may be spuriously high by a few decibels, with the error increasing as the frequency decreases. The error results from masking of the occluded-ear threshold by physiological noise during testing. 2 Normative references The following referenced documents are indispensable for the application 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. IEC 60263, Scales and sizes for plotting frequency characteristics and polar diagrams IEC 60645-1, Electroacoustics Audiological equipment Part 1: Pure-tone audiometers IEC 61260:1995, Electroacoustics Octave-band and fractional-octave-band filters lEC 61672-1, Electroacoustics Sound level meters Part 1: Specifications Guide to the expression of uncertainty in measurement (GUM), BIPM/IEC/IFCC/ISO/IUPAC/IUPAP/OIML, ISBN 92-67-10188-9, 1993 3) 3) Corrected and reprinted in 1995. DD ISO/TS 4869-5:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:07:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 3 Terms and definitions For the purpose of this document, the following terms and definitions apply. 3.1 hearing protector device worn by a person to reduce unwanted effects of sound NOTE Hearing protectors can 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 eardrum. 3.2 ear-muff 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 NOTE 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 hearing protector that either is inserted into the external ear canal or covers the ear canal entrance NOTE Some ear-plugs are held in place by a lightweight band. They are sometimes called canal caps, semi-aural inserts, or banded ear-plugs. 3.4 helmet 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 389-1. 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 measurement procedures see, for example, ISO 6189 and ISO 8253-1. 3.7 threshold of hearing lowest sound pressure level at which, under specified conditions, a person gives a predetermined percentage of correct detection responses on repeated trials NOTE For the purpose of this Technical Specification, the threshold of hearing is measured with and without the hearing protector. For appropriate test conditions, see ISO 8253-2. 3.8 occluded-ear threshold of hearing threshold of hearing when a hearing protector is worn 3.9 open-ear threshold of hearing threshold of hearing when no hearing protect