SIST EN IEC 61252:2026

SLOVENSKI STANDARD
oSIST prEN IEC 61252:2024
01-september-2024
Elektroakustika - Merilniki osebne izpostavljenosti zvoku
Electroacoustics - Personal sound exposure meters
Elektroakustik - Anforderungen an Personenschallexposimeter
électroacoustique - Exposimètres acoustiques individuels
Ta slovenski standard je istoveten z: prEN IEC 61252:2024
ICS:
13.140 Vpliv hrupa na ljudi Noise with respect to human
beings
17.140.50 Elektroakustika Electroacoustics
oSIST prEN IEC 61252:2024 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN IEC 61252:2024
oSIST prEN IEC 61252:2024
29/1180/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61252 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2024-08-02 2024-10-25
SUPERSEDES DOCUMENTS:
29/1153/CD, 29/1157A/CC
IEC TC 29 : ELECTROACOUSTICS
SECRETARIAT: SECRETARY:
Denmark Ms Lise Aagesen
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:

Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some
Countries” clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is
the final stage for submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).
TITLE:
Electroacoustics - Personal sound exposure meters
PROPOSED STABILITY DATE: 2025
NOTE FROM TC/SC OFFICERS:
At its meeting April 2024 in Warsaw, IEC/TC 29 took the following decision, doc. 29/1174/DL, refers:
DECISION 1
TC 29 decides to proceed with 2CD IEC 61252 "Electroacoustics – Personal sound exposure meters"
as a CDV with the following target dates:
CDV: 2024-08-31
FDIS: 2025-08-31
Publication: 2025-11-30.
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

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2 CONTENTS
3 FOREWORD. 5
4 INTRODUCTION . 7
5 1 Scope . 8
6 2 Normative references . 9
7 3 Terms and definitions . 9
8 4 Performance specifications . 13
9 4.1 General performance requirements . 13
10 4.1.1 Components . 13
11 4.1.2 Display device . 14
12 4.1.3 Configuration . 14
13 4.1.4 Design features . 15
14 4.1.5 Adjustment at the calibration check frequency . 16
15 4.1.6 Determination of conformance . 17
16 4.1.7 Reference environmental conditions . 17
17 4.1.8 Classification for radio-frequency tests . 17
18 4.2 Marking . 18
19 4.3 Static pressure . 18
20 4.4 Temperature . 18
21 4.5 Relative humidity . 18
22 4.6 Electrostatic discharge . 18
23 4.7 A.C.-power-frequency and radio-frequency fields . 18
24 4.8 Radio-frequency emissions and disturbances to a public power supply . 19
25 4.9 Directional response . 19
26 4.10 Frequency weightings. 19
27 4.11 Corrections to indicated levels . 20
28 4.11.1 General . 20
29 4.11.2 Windscreens . 20
30 4.11.3 Corrections for use during periodic testing . 21
31 4.12 Linearity of response to steady signals . 21
32 4.13 Under-range indication . 21
33 4.14 Time-weightings F and S . 21
34 4.15 Response to short duration signals for indications of time-averaged sound
35 levels, sound exposure levels, and time-weighted sound levels . 21
36 4.16 Response to short duration signals for indications of time-averaged non-
37 equal-energy sound levels . 22
38 4.17 Overload indication . 23
39 4.18 C-weighted peak sound level . 23
40 4.18.1 Deviation from reference differences . 23
41 4.18.2 Repeatability . 23
42 4.19 Stability during continuous operation . 23
43 4.20 High-level stability . 23
44 4.21 Reset facility . 23
45 4.22 Analogue or digital output . 23
46 4.23 Timing facilities . 23
47 4.24 Crosstalk . 24
48 4.25 Power supply . 24
49 4.26 Pause and resumption of time averaging and time integration . 24
50 4.27 Instruction Manual . 24

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51 4.27.1 General . 24
52 4.27.2 Specifications . 24
53 4.27.3 Information for operation . 26
54 4.27.4 Information for use with auxiliary devices . 27
55 4.27.5 Information for testing . 27
56 5 Pattern-evaluation tests . 28
57 5.1 General requirements . 28
58 5.1.1 Submission for testing . 28
59 5.1.2 Display device . 29
60 5.1.3 Configuration . 29
61 5.1.4 Design features . 29
62 5.1.5 Adjustment at the calibration check frequency . 30
63 5.1.6 Determination of conformance . 30
64 5.1.7 Environmental conditions . 31
65 5.1.8 Laboratory equipment . 31
66 5.2 Marking and information in the Instruction Manual . 31
67 5.3 Static pressure . 32
68 5.4 Temperature . 32
69 5.5 Relative humidity . 32
70 5.6 Electrostatic discharge . 32
71 5.7 Influence of a.c-power-frequency and radio-frequency fields . 32
72 5.8 Radio-frequency emissions and public power supply disturbances . 32
73 5.9 Directional response . 32
74 5.10 Frequency weightings. 32
75 5.10.1 Acoustical signal tests of frequency weightings . 32
76 5.10.2 Electrical signal tests of frequency weightings . 32
77 5.11 Corrections to indicated levels . 33
78 5.12 Linearity of response to steady signals . 33
79 5.13 Under-range indication . 33
80 5.14 Decay time constants for time weightings F and S . 33
81 5.15 Response to short-duration signals for indications of time-averaged sound
82 levels, sound exposure levels, and time-weighted sound levels . 33
83 5.16 Response to short-duration signals for indications of time-averaged non-
84 equal-energy sound levels . 33
85 5.17 Overload indication . 34
86 5.18 C-weighted peak sound level . 34
87 5.18.1 Deviation from reference differences . 34
88 5.18.2 Repeatability . 34
89 5.19 Stability during continuous operation . 34
90 5.20 High-level stability . 34
91 5.21 Reset facility . 34
92 5.22 Outputs . 35
93 5.23 Timing facilities . 35
94 5.24 Crosstalk in multi-channel personal sound exposure meters . 35
95 5.25 Power supply . 35
96 5.26 Pause and resumption of time averaging and time integration . 35
97 5.27 Pattern evaluation report . 35
98 6 Periodic tests . 36
99 6.1 General requirements . 36
100 6.1.1 Submission for testing . 36

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101 6.1.2 Preliminary inspection . 37
102 6.1.3 Configuration . 37
103 6.1.4 Design features . 37
104 6.1.5 Adjustment at the calibration check frequency . 38
105 6.1.6 Determination of conformance . 38
106 6.1.7 Environmental conditions . 39
107 6.1.8 Laboratory equipment . 39
108 6.1.9 Power supply . 39
109 6.2 Marking . 39
110 6.3 Frequency weightings. 40
111 6.3.1 Acoustical signal tests of a frequency weighting . 40
112 6.3.2 Electrical signal tests of frequency weightings . 40
113 6.4 Frequency and time weightings at 1 kHz . 40
114 6.5 Linearity of response to steady signals . 40
115 6.6 Overload indication . 40
116 6.7 C-weighted peak sound level . 40
117 6.7.1 Deviation from reference differences . 40
118 6.7.2 Repeatability . 40
119 6.8 Documentation . 41
120 Annex A (informative) Sound exposures and corresponding normalized 8 h-average
121 sound levels . 43
122 Annex B (informative)  Relationship between tolerance interval, corresponding
123 acceptance interval and the maximum-permitted uncertainty of measurement . 44
124 Annex C (normative) Maximum-permitted uncertainties of measurement . 46
125 Annex D (informative) Example assessments of conformance to specifications of this
126 document . 47
127 D.1 General . 47
128 D.2 Conformance criteria . 47
129 D.3 Example test results . 47
130 Bibliography . 50
132 Figure B.1 – Relationship between tolerance interval, corresponding acceptance
133 interval and the maximum-permitted uncertainty of measurement . 44
134 Figure D.1 – Examples of assessment of conformance . 49
136 Table 1 – Acceptance limits for deviations of directional response from the design goal . 19
137 Table 2 – Reference response to a sequence of repeated 4 kHz tonebursts for time-
138 averaged non-equal-energy sound levels and acceptance limits . 22
139 Table A.1 – Sound exposures and corresponding normalized 8 h-average sound levels . 43
140 Table C.1 – Maximum-permitted uncertainties of measurement for a coverage
141 probability of 95 % for the response to short-duration signals for indications of time-
142 averaged non-equal-energy sound levels and for timing facilities . 46
143 Table D.1 – Examples of assessment of conformance . 48
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147 INTERNATIONAL ELECTROTECHNICAL COMMISSION
148 ____________
150 ELECTROACOUSTICS –
151 PERSONAL SOUND EXPOSURE METERS
154 FOREWORD
155 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
156 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
157 co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
158 in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
159 Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
160 preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
161 may participate in this preparatory work. International, governmental and non-governmental organizations liaising
162 with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
163 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
164 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
165 consensus of opinion on the relevant subjects since each technical committee has representation from all
166 interested IEC National Committees.
167 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
168 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
169 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
170 misinterpretation by any end user.
171 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
172 transparently to the maximum extent possible in their national and regional publications. Any divergence between
173 any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
174 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
175 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
176 services carried out by independent certification bodies.
177 6) All users should ensure that they have the latest edition of this publication.
178 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
179 members of its technical committees and IEC National Committees for any personal injury, property damage or
180 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
181 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
182 Publications.
183 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
184 indispensable for the correct application of this publication.
185 9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
186 patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
187 respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
188 may be required to implement this document. However, implementers are cautioned that this may not represent
189 the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
190 shall not be held responsible for identifying any or all such patent rights.
191 IEC 61252 has been prepared by IEC technical committee 29: Electroacoustics. It is an
192 International Standard.
193 This second edition cancels and replaces the first edition published in 1993,
194 Amendment 1:2000, and Amendment 2:2017. This edition constitutes a technical revision.
195 This edition includes the following significant technical changes with respect to the previous
196 edition:
197 a) personal sound exposure meters are required to provide indications of time-averaged sound
198 level and peak sound level;
199 b) sound exposure is an optional quantity for indication;
200 c) specifications for physical quantities that do not follow the principle of equal-energy
201 exchange rate have been added;
202 d) specifications for directional response have been added;

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203 e) specifications for frequency weightings apply to the relative diffuse-field frequency
204 response;
205 f) determination of conformance to specifications takes account of uncertainties of
206 measurement;
207 g) detailed requirements for pattern-evaluation tests and periodic testing have been added.
208 The text of this International Standard is based on the following documents:
Draft Report on voting
XX/XX/FDIS XX/XX/RVD
210 Full information on the voting for its approval can be found in the report on voting indicated in
211 the above table.
212 The language used for the development of this International Standard is English.
213 This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
214 accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
215 at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
216 described in greater detail at www.iec.ch/publications.
217 The committee has decided that the contents of this document will remain unchanged until the
218 stability date indicated on the IEC website under webstore.iec.ch in the data related to the
219 specific document. At this date, the document will be
220 • reconfirmed,
221 • withdrawn,
222 • replaced by a revised edition, or
223 • amended.
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225 INTRODUCTION
226 The principal application for a personal sound exposure meter is the measurement of sound
227 immission in the vicinity of a person’s head, for example for assessment of occupational noise
228 exposure in accordance with International Standards such as ISO 1999 and ISO 9612.
229 The microphone of a personal sound exposure meter is typically worn on the shoulder, collar,
230 or other location close to the ear. In many practical situations the sound immission indicated by
231 an instrument worn on a person is likely to be different from that which would be measured in
232 the absence of a person. The influence of the person wearing a personal sound exposure meter
233 should be considered when estimating the sound immission that would have been measured
234 with the person absent.
235 The most common physical quantities for characterisation of sound immission are time-
236 averaged sound levels and peak sound levels. For this reason, this document requires a
237 personal sound exposure meter to provide indications of these sound levels.
238 It is also sometimes required to measure other quantities including sound exposure or sound
239 exposure levels. Therefore, this document optionally allows a personal sound exposure meter
240 to indicate these quantities.
241 Sound exposure is a physical measure that accounts for both the sound pressure and its
242 duration, at a given location, through the time integral of the square of the instantaneous
243 frequency-weighted sound pressure. A doubling (or halving) of the integration time of a constant
244 sound level yields a doubling (or halving) of sound exposure. Similarly, an increase (or
245 decrease) of 3 dB in a constant input sound level for a constant integration time yields a
246 doubling (or halving) of the sound exposure. The same operating principle (“equal-energy
247 exchange rate”) underlies the measurement of sound exposure level.
248 The term “dose” is sometimes used to refer to a percentage of a predetermined criterion for
249 exposure to noise in terms of a specified upper limit (often a legal limit) of a specified physical
250 quantity. The physical quantity and the value of the limit vary between jurisdictions, and some
251 jurisdictions specify quantities that are not based on the principle of equal-energy exchange.
252 Therefore, this document allows a personal sound exposure meter to indicate these quantities
253 and distinguishes between equal-energy-based and non-equal-energy-based quantities.
254 The title of this edition of the document has been changed because this edition includes
255 requirements for pattern-evaluation tests and periodic testing in addition to performance
256 specifications.
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260 ELECTROACOUSTICS –
261 PERSONAL SOUND EXPOSURE METERS
265 1 Scope
266 This document specifies
267 – performance specifications for personal sound exposure meters,
268 – details of the tests necessary to verify conformance to all mandatory specifications for the
269 purpose of pattern evaluation, and
270 – procedures for periodic testing of a personal sound exposure meter.
271 Personal sound exposure meters conforming to the requirements of this standard have a
272 specified frequency response for sound incident on the microphone from all directions.
273 This document is applicable to instruments that are designed to be worn on a person in a
274 configuration specified by the manufacturer for the measurement of sound immission resulting
275 from steady, intermittent, fluctuating, irregular, or impulsive sounds. For reproducibility of
276 results, specifications and tests for the response to sound waves apply without an operator
277 present in the sound field.
278 This document specifies performance requirements for personal sound exposure meters of one
279 performance class. The specifications generally correspond to those for a class 2 integrating-
280 averaging sound level meter as given in IEC 61672-1:2013 for an A-weighted sound pressure
281 level range at least from 67 dB to 137 dB and a nominal frequency range from 20 Hz to 8 kHz.
282 The design goals and the acceptance limits for deviations from the design goals are
283 representative of the performance of practical instruments. Personal sound exposure meters
284 are unlikely to be suitable for measurement of sound levels outside these ranges.
285 Pattern evaluation tests and periodic tests described in this edition of this document apply to
286 personal sound exposure meters for which the manufacturer claims conformance to the
287 specifications given in this edition of this document.
288 The purpose of pattern evaluation is to determine whether a model of personal sound exposure
289 meter conforms to all the performance specifications given in this document.
290 The purpose of periodic testing is to assure the user that the individual personal sound exposure
291 meter conforms to the applicable performance specifications for a limited set of key tests and
292 for the environmental conditions under which the tests are performed. The extent of the periodic
293 tests is deliberately restricted to the minimum considered necessary. Because of the limited
294 extent of the periodic tests, evidence of pattern approval is necessary to state that the individual
295 personal sound exposure meter conforms to the complete set of specifications of this document.
296 The aim is to ensure that pattern evaluation and periodic testing are performed in a consistent
297 manner by all laboratories.
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301 2 Normative references
302 The following documents are referred to in the text in such a way that some or all of their content
303 constitutes requirements of this document. For dated references, only the edition cited applies.
304 For undated references, the latest edition of the referenced document (including any
305 amendments) applies.
306 ISO/IEC Guide 98-3, Uncertainty of measurement – Part 3: Guide to the expression of
307 uncertainty in measurement (GUM:1995)
308 ISO/IEC Guide 98-4, Uncertainty of measurement – Part 4: Role of measurement uncertainty
309 in conformity assessment
310 ISO/IEC Guide 99, International vocabulary of metrology – Basic and general concepts and
311 associated terms (VIM)
312 IEC 60942, Electroacoustics – Sound calibrators
313 IEC 61000-4-3:2020, Electromagnetic compatibility (EMC) – Part 4-3: Testing and
314 measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test
315 IEC 61094-6, Electroacoustics – Measurement microphones – Part 6: Electrostatic actuators
316 for determination of frequency response
317 IEC 61183, Electroacoustics – Random-incidence and diffuse-field calibration of sound level
318 meters
319 IEC 61672-1:2013, Electroacoustics – Sound level meters – Part 1: Specifications
320 IEC 61672-2:2013, Electroacoustics – Sound level meters – Part 2: Pattern evaluation tests
321 IEC 61672-3:2013, Electroacoustics – Sound level meters – Part 3: Periodic tests
322 IEC 62585:2012, Electroacoustics – Methods to determine corrections to obtain the free-field
323 response of a sound level meter
324 3 Terms and definitions
325 For the purposes of this document, the terms and definitions given in ISO/IEC Guide 98-3,
326 ISO/IEC Guide 98-4, ISO/IEC Guide 99, IEC 61000-4-3, IEC 61183, IEC 61672 (all parts), and
327 IEC 62585 and the following apply.
328 ISO and IEC maintain terminology databases for use in standardization at the following
329 addresses:
330 • IEC Electropedia: available at https://www.electropedia.org/
331 • ISO Online browsing platform: available at https://www.iso.org/obp
332 3.1
333 sound exposure
334 time integral of the square of a frequency-weighted sound pressure signal over a stated time
335 interval or event of stated duration
336 Note 1 to entry: Duration of integration is included implicitly in the time integral and is not always reported explicitly,
337 although it is useful to state the nature of the event. For measurements of sound exposure over a specified time
338 interval, duration of integration is usually reported and indicated by a suitable subscript to the letter symbol, for
339 example as E .
A,1 h
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340 Note 2 to entry: In symbols and as an example, A-weighted sound exposure E is represented by
A,T
t
341 E = p (t)dt (1)
A,T A
∫
t
342 where pt() is the square of the A-weighted sound-pressure signal during integration time T starting at t and
A
343 ending at t .
344 Note 3 to entry: The unit of sound exposure is pascal-squared seconds (Pa s) if sound pressure is in pascals and
345 running time is in seconds.
346 Note 4 to entry: For applications such as measurement of exposure to noise in the workplace, sound exposure in
347 pascal-squared hours is more convenient than pascal-squared seconds.
348 [SOURCE: IEC 61672-1:2013, 3.11]
349 3.2
350 normalized 8 h-average sound level
351 level of the time-mean-square, A-weighted sound pressure during a normalization time period
352 T of 8 h such that the sound exposure therefrom is equal to that of a time-varying sound at a
n
353 place where total sound exposure occurs within a time period not necessarily 8 h
354 Note 1 to entry: The unit of normalized 8 h-average sound level is decibels.
355 Note 2 to entry: In symbols, a normalized 8 h-average sound level (letter symbol L ), relative to the reference
Aeq,8 hn
356 sound pressure p and the 8 h normalization time period T , is related to sound exposure E in pascal-squared hours
0 n
357 by
 
359 L = 10lg E pT (2)
Aeq,8 hn ( 0 n)
 
 
360 or, alternatively, by:
0,1×L
( )
2 Aeq,8 hn
361 E= pT 10 (3)
( 0n)

362 Note 3 to entry: For computations, a simpler form of Eq.(2) for normalized 8 h-average sound level is obtained, for
363 sound exposure E in pascal-squared hours, after substituting the values of 20 µPa for p and 8 h for T , as
0 n
 
365 LE10lg×10 3,2 (4)
Aeq,8 hn ( )
 
 
366 Note 4 to entry: When a total sound exposure is described indirectly by an A-weighted time-averaged sound
367 pressure level L , for an averaging time T greater or less than the normalization time period of 8 h, normalized
Aeq,T
368 8 h-average sound level may be determined from
370  (5)
L L +10lg(TT )
Aeq,8 hn Aeq,T n
371 Note 5 to entry: Annex A provides a table of normalized 8 h-average sound levels and corresponding sound
372 exposures. For example, a sound exposure of 1 Pa h (irrespective of the period of time over which it is measured)
373 corresponds to a normalized 8 h-average sound level of approximately 85 dB; a sound exposure of 3,20 Pa h
374 corresponds to a normalized 8 h-average sound level of 90 dB.
375 Note 6 to entry: Normalized 8 h-average sound level in Eq.(2) is identical to "daily personal noise exposure” (L )
EX,8h
376 defined in Article 2 of Directive 2003/10/EC of the European Parliament and of the Council of 6 February 2003 on
377 the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical
378 agents (noise).
379 Note 7 to entry: Normalized 8 h-average sound level in Eq.(2) is also the same as "noise exposure level normalized
380 to a nominal 8 h working day, L " defined in ISO 1999.
EX,8 h
=
=
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381 3.3
382 exchange rate
383 change in sound level corresponding to a doubling or halving of the duration of a steady input
384 sound pressure signal while a constant percentage non-equal-energy sound exposure is
385 maintained
386 3.4
387 non-equal-energy sound exposure
388 time integral of a power function of the time-weighted square of a frequency-weighted sound
389 pressure signal over a stated time interval or event of stated duration
390 Note 1 to entry: Duration of integration is included implicitly in the time integral and is not always reported explicitly,
391 although it is useful to state the nature of the event. For measurements of non-equal-energy sound exposure over a
392 specified time interval, duration of integration is usually reported and indicated by a suitable subscript to the letter
393 symbol, for example as E .
neeA,1 h
394 Note 2 to entry: In symbols and as an example, A-frequency weighted F-time weighted non-equal-energy sound
395 exposure E is represented by
neeAF,T
10lg(2) Q

t t
2 − t−ξτ
  2 ( )
F

397  (6)
Ep= (ξξ)ed dt
neeAF,T   A

∫∫
τ
t −∞

 F
1 

398 where:
399 - τ is the exponential time constant in seconds for the F time weighting;
F
400 - ξ is a dummy variable of time integration from some time in the past, as indicated by -∞ for the lower limit
401 of the integral, to the time of observation t;
402 - p (ξ) is the A-weighted instantaneous sound-pressure signal;
A
403 - Q is the exchange rate in decibels;
404 - T is the integration time beginning at t and ending at t .
1 2
405 Note 3 to entry: The unit of sound exposure is pascal-squared seconds (Pa s) if sound pressure is in pascals and
406 running time is in seconds.
407 Note 4 to entry: For applications such as measurement of exposure to noise in the workplace, sound exposure in
408 pascal-squared hours is more convenient than pascal-squared seconds.
409 Note 5 to entry: If the exchange rate were 3 dB and there were no time weighting, non-equal-energy sound exposure
410 would be equivalent to sound exposure.
411 3.5
412 criterion duration
413 specified duration of time integration
414 Note 1 to entry: The criterion duration is typically chosen to be the maximum duration of exposure for the application,
415 for example the duration of a working day.
416 3.6
417 criterion sound level
418 specified level of a sound
419 Note 1 to entry: The criterion sound level is typically chosen to be a level of sound which, if maintained for longer
420 than the criterion duration or if exceeded, could have adverse effects.
421 3.7
422 criterion sound exposure
423 product of the criterion duration and the mean-square sound pressure corresponding to the
424 criterion sound level
425 Note 1 to entry: The criterion sound exposure is typically chosen to be a legal limit. Such limits vary between
426 jurisdictions and are subject to change.

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427 3.8
428 criterion non-equal-energy sound exposure
429 product of the criterion duration and a power function of the mean-square sound pressure
430 corresponding to the criterion sound level
431 Note 1 to entry: The criterion non-equal-energy sound exposure is typically chosen to be a legal limit. Such limits
432 vary between jurisdictions and are subject to change.
433 3.9
434 percentage criterion sound exposure
435 quotient of sound exposure to criterion sound exposure, multiplied by 100
436 Note 1 to entry: The unit of percentage criterion sound exposure is per cent.
437 Note 2 to entry: In symbols and as an example, the percentage criterion sound exposure using frequency weighting
438 A can also be calculated from:
t
0,1 LL−
2 ( )
A cr
440 DT=(100 ) 10 dt (7)
A cr
∫
t
441 where:
442 - T is the criterion duration;
cr
443 - the integration time begins at t and ends at t ;
1 2
444 - L is the A-frequency weighted sound level equivalent to the A-frequency-weighted input sound pressure;
A
446 - L is the criterion sound level.
cr
447 3.10
448 percentage criterion non-equal-energy sound exposure
449 quotient of non-equal-energy sound exposure to criterion non-equal-energy sound exposure,
450 multiplied by 100
451 Note 1 to entry: The unit of percentage criterion non-equal-energy sound exposure is per cent.
452 Note 2 to entry: In symbols and as an example, the percentage criterion non-equal-energy sound exposure using
453 frequency weighting A and time weighting S can also be calculated from:
t
LL− lg(2) Q
2 ( )( )
AS cr

455 DT= 100 10 dt (8)
( )
ASQ cr
∫
t
456 where:
457 - Q is the exchange rate in decibels;
458 - T is the criterion duration;
cr
459 - the integration time begins at t and ends at t ;
1 2
460 - L is the S-time-weighted A-frequency-weighted sound level equivalent to the A-frequency-weighted input
AS
461 sound pressure;
462 - L is the criterion sound level.
cr
463 Note 3 to entry: If the exchange rate were 3 dB and there were no time weighting, percentage criterion non-equal-
464 energy sound exposure would be equivalent to percentage criterion sound exposure.
465 3.11
466 time-averaged non-equal-energy sound level
467 average sound level during the integration time over which a percentage criterion non-equal-
468 energy sound exposure is measured
469 Note 1 to entry: In symbols and as an example, the time-averaged non-equal-energy sound level using frequency
470 weighting A and time-weighting S can be calculated from:
472 L L+ Q lg(2) lg DT 100T (9)
( ) ( )
neeAS,T cr ASQ cr
473 where:
474 - Q is the exchange rate in decibels;
=
oSIST prEN IEC 61252:2024
IEC CDV 61252 © IEC 2024 – 13 – 29/1180/CDV
475 - D is the percentage criterion non-equal-energy sound exposure;
ASQ
476 - T is the criterion duration;
cr
477 - T is the integration time;
478 - L is the criterion sound level.
cr
479 Note 2 to entry: If the sound level is held constant during a test, time-averaged non-equal-energy sound level is
480 that constant level.
481 Note 3 to entry: If the exchange rate were 3 dB and there were no time weighting, time-averaged non-equal-energy
482 sound level is a close approximation of time-averaged sound level.
483 Note 4 to entry: Time-averaged non-equal-energy sound level is equivalent to average sound level as described in
484 ANSI S1.25-1991, 4.7.
485 4 Performance specifications
486 4.1 General performance requirements
487 4.1.1 Components
488 Generally, a personal sound exposure meter is a combination of a microphone, a signal
489 processor, and a display device.
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