IEC 61252:1993

Electroacoustics - Specifications for personal sound exposure meters

Applies to instruments for measurement of A-frequency- weighted sound exposure resulting from steady, intermittent, fluctuating, irregular, or impulsive sound. Specifies acoustical and electrical performance requirements for personal sound exposure meters of one accuracy grade.

Electroacoustique - Spécifications des exposimètres acoustiques individuels

S'applique aux instruments de mesure de l'exposition sonore pondérée A en fréquence et résultant de sons stables, intermittents, fluctuants, irréguliers, ou impulsifs. Donne les prescriptions concernant les caractéristiques acoustiques et électriques des exposimètres acoustiques individuels correspondant à une seule classe de précision.

General Information

• Status: Published
• Publication Date: 05-Apr-2017
• ICS: 13.140 - Noise with respect to human beings
• ICS: 17.140.50 - Electroacoustics
• Technical Committee: TC 29 - Electroacoustics
• Current Stage: PPUB - Publication issued
• Start Date: 25-Jun-1993
• Completion Date: 31-Dec-1992

Relations

• Amended By: IEC 61252:1993/AMD1:2000 - Amendment 1 - Electroacoustics - Specifications for personal sound exposure meters
• Effective Date: 05-Sep-2023
• Amended By: IEC 61252:1993/AMD2:2017 - Amendment 2 - Electroacoustics - Specifications for personal sound exposure meters
• Effective Date: 05-Sep-2023
• Revised: IEC 61252:2025 - Electroacoustics - Personal sound exposure meters
• Effective Date: 05-Sep-2023

Overview

IEC 61252:1993 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies requirements for personal sound exposure meters used in electroacoustics. These specialized instruments are designed to measure A-frequency-weighted sound exposure, capturing sound resulting from a variety of sources including steady, intermittent, fluctuating, irregular, or impulsive noise. The standard outlines acoustical and electrical performance specifications to ensure reliable and accurate sound exposure measurement, focusing on one accuracy grade.

Personal sound exposure meters play a crucial role in occupational health and safety by assessing noise exposure levels near a person’s head, offering vital data for hearing impairment prevention and compliance with occupational noise regulations.

Key Topics

• Scope and Measurement
  IEC 61252 applies to devices measuring sound exposure as the time integral of the square of instantaneous A-frequency-weighted sound pressure. This measure accounts for both sound pressure intensity and exposure duration, providing a comprehensive evaluation of noise dose.

• Performance Requirements
  The standard specifies stringent acoustical and electrical parameters including frequency weighting (A-weighting), linearity to steady and short-duration signals, response to unipolar pulses, and environmental sensitivity. This ensures meter accuracy during real-world use in diverse noise conditions.

• Instrument Functionality
  Sound exposure meters under this standard are expected to accurately display sound exposure in pascal-squared hours (Pa²h), or provide a conversion method when other units such as percentage noise dose are used. The meters integrate sound energy over time and include overload indicators and electromagnetic compatibility criteria.

• Testing and Calibration
  The standard introduces recommended tests to verify meter performance, including linearity testing with 1 kHz steady signals and response to brief tone bursts. It also specifies emission limits and marking requirements for traceability and user guidance.

• Application Focus
  The personal sound exposure meter’s microphone is designed to attach close to the ear (shoulder, collar), capturing representative noise exposure relevant to occupational environments. Directional microphone response is not strictly specified due to wearer variability.

Applications

• Occupational Noise Monitoring
  IEC 61252-compliant personal sound exposure meters are extensively used in workplace environments such as factories, construction sites, and airports to monitor workers’ noise exposure. This aids in preventing hearing loss by ensuring regulatory noise limits are respected.

• Hearing Conservation Programs
  Industrial hygienists and safety professionals utilize these meters to assess the risk of hearing impairment according to health standards like ISO 1999. The accurate integration of fluctuating and impulsive noise assists in designing effective hearing protection strategies.

• Research and Noise Assessment
  Researchers studying noise pollution and its effects can benefit from the meter’s precise measurement capabilities. The standardization ensures data comparability across international studies.

• Compliance and Certification
  Organizations use IEC 61252 to select calibrated, compliant devices for legal noise exposure reporting. The uniform measurement approach facilitates international regulatory compliance and benchmarking.

Related Standards

• IEC 60804
  This standard relates to integrating sound level meters which share foundational measurement principles with IEC 61252, but differ primarily in specifying equivalent-continuous frequency-weighted sound pressure levels rather than sound exposure.

• ISO 1999
  Provides methods for predicting noise-induced hearing loss, for which IEC 61252 sound exposure metrics serve as critical input data.

• IEC Electromagnetic Compatibility (EMC) Standards
  As IEC 61252 includes EMC requirements, related IEC EMC standards ensure personal sound exposure meters operate reliably without interference in diverse electromagnetic environments.

• Occupational Safety Regulations
  National and international noise exposure regulations, such as OSHA or EU directives, often reference or align with IEC 61252-compliant devices for sound monitoring and compliance.

---

Keywords: IEC 61252, personal sound exposure meter, A-frequency weighting, sound exposure measurement, noise dose meter, occupational noise monitoring, hearing conservation, electromagnetic compatibility, electroacoustics standards.

Standards Content (Sample)

IEC 61252 ®
Edition 1.2 2017-04
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
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Electroacoustics – Specifications for personal sound exposure meters

Electroacoustique – Spécifications des exposimètres acoustiques individuels

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IEC 61252 ®
Edition 1.2 2017-04
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electroacoustics – Specifications for personal sound exposure meters

Electroacoustique – Spécifications des exposimètres acoustiques individuels

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.140; 17.140.50 ISBN 978-2-8322-4227-8

IEC 61252 ®
Edition 1.2 2017-04
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Electroacoustics – Specifications for personal sound exposure meters

Electroacoustique – Spécifications des exposimètres acoustiques individuels

– 2 – IEC 61252:1993+AMD1:2000
+AMD2:2017  IEC 2017
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references. 6
3 Definitions . 7
4 General performance requirements . 9
5 Reference conditions . 11
6 Absolute acoustical sensitivity . 11
7 Frequency weighting . 11
8 Linearity of response to steady signals . 12
9 Response to short-duration signals . 13
10 Response to unipolar pulses . 14
11 Latching overload indicator . 14
12 Sensitivity to various environments . 14
13 Instrument marking . 15
14 Instruction Manual . 15
15 Electromagnetic and electrostatic compatibility requirements and test procedures . 17
Annex A (informative)  Sound exposures and corresponding normalized 8-h-average
sound levels . 22
Annex B (informative)  Recommended tests to verify the performance of a personal
sound exposure meter . 23
Annex C (informative)  Emission limits. 27

Figure 1 – Functional elements of a personal sound exposure meter . 10

Table 1 – Design-goal A-frequency weighting relative to response at 1 kHz
and the tolerances ∆A that apply to the performance of a complete personal sound
exposure meter . 12
Table A.1 – Sound exposures and corresponding normalized 8-h-average sound levels . 22
Table B.1 – Minimum set of target conditions for 1 kHz steady-signal linearity tests . 24
Table B.2 – Conditions for testing response to short-duration signals . 25
Table C.1 – Limits for radiated disturbance of class B ITE at a measuring distance
of 10 m . 27

+AMD2:2017  IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS –
SPECIFICATIONS FOR PERSONAL SOUND EXPOSURE METERS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This consolidated version of the official IEC Standard and its amendments has been prepared
for user convenience.
IEC 61252 edition 1.2 contains the first edition (1993-06) [documents 29(CO)162 and
29(CO)168], its amendment 1 (2000-10) [documents 29/457/FDIS and 29/471/RVD] and its
amendment 2 (2017-04) [documents 29/910/CDV and 29/936/RVC].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendments 1 and 2. Additions are in green text, deletions are in strikethrough red
text. A separate Final version with all changes accepted is available in this publication.

– 4 – IEC 61252:1993+AMD1:2000
+AMD2:2017  IEC 2017
International Standard IEC 61252 has been prepared by IEC technical committee 29:
Electroacoustics.
Specifications in this International Standard for personal sound exposure meters are
consistent, insofar as practical, with comparable specifications in IEC 60804 for integrating
sound level meters. The four principal technical differences from the specifications in the 1985
issue of IEC 60804 are:
a) sound exposure is measured and displayed rather than equivalent-continuous frequency-
weighted sound pressure level or sound exposure level;
b) accuracy of squaring and integrating short-duration signals is specified by measurement of
the sound exposure of a sequence of repeated constant-amplitude, 1 ms and 10 ms
duration, 4 kHz tonebursts rather than by measurement of the response to single 4 kHz
tonebursts of varying amplitudes with durations ranging from 1 ms to 1 s, each single
toneburst being accompanied by a continuous, in-phase, low-level, 4 kHz background
signal;
c) specifications for a personal sound exposure meter include a limitation on the difference
between the sound exposure indicated in response to positive-going and negative-going
unipolar pulses; and
d) requirements are not specified for the directional response of the microphone of a personal
sound exposure meter intended to be worn on a person.
This International Standard includes two informative annexes. Annex A provides a table of
selected sound exposures and corresponding normalized 8-h-average sound levels. Annex B
describes recommendations for tests to verify the performance of a personal sound exposure
meter.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

+AMD2:2017  IEC 2017
INTRODUCTION
According to this International Standard, a personal sound exposure meter is intended to
measure sound exposure as the time integral of the square of the instantaneous A-frequency-
weighted sound pressure. This operating principle underlies the measurement of sound
exposure level according to IEC 60804. It is the "equal-energy exchange rate" whereby a
doubling (or halving) of the integration time of a constant sound level yields a two-fold increase
(or decrease) of sound exposure. Similarly, an increase (or decrease) of 3 dB in a constant
input sound level for a constant integration time yields a doubling (or halving) of the sound
exposure.
Noise dose meters usually have been designed to indicate noise dose as a percentage of a
legal limit. The limit and its definition vary from country to country and are subject to change.
To facilitate international comparison of sound exposure records with numerical values of
convenient magnitude, this International Standard specifies an instrument that indicates sound
exposure in pascal-squared hours. An indication of sound exposure with a unit other than
pascal-squared hours is permitted provided the manufacturer specifies a procedure for
converting the indication to pascal-squared hours, for example, a display of "dose" as a fraction
or a percentage of a specified sound exposure in pascal-squared hours.
The principal application for a personal sound exposure meter is the measurement of sound
exposure in the vicinity of a person's head; e.g., for assessment of potential hearing
impairment according to Standards such as ISO 1999. The microphone of a personal sound
exposure meter may be worn on the shoulder, collar, or other location close to one ear. For
many practical situations, such as in a factory where the sound-incidence angle may vary
widely during the course of workday, the sound exposure indicated by an instrument worn on a
person is likely to be different from that which would be measured in the absence of the
person. The influence of the person wearing a personal sound exposure meter should be
considered when estimating the sound exposure that would have been measured with the
person absent.
– 6 – IEC 61252:1993+AMD1:2000
+AMD2:2017  IEC 2017
ELECTROACOUSTICS –
SPECIFICATIONS FOR PERSONAL SOUND EXPOSURE METERS

1 Scope
1.1 Sound exposure is a physical measure that accounts for both the sound pressure and its
duration, at a given location, through an integral-over-time of the square of instantaneous
frequency-weighted sound pressure.
1.2 This International Standard is applicable to instruments for measurement of A-frequency-
weighted sound exposure resulting from steady, intermittent, fluctuating, irregular, or impulsive
sounds. Instruments complying with the specifications of this International Standard are
intended to be worn on a person to measure sound exposure. Measurements of sound
exposure in the workplace may be useful for determinations of occupational noise exposure, in
accordance with ISO 1999 and ISO 9612.
1.3 This International Standard specifies acoustical and electrical performance requirements
for personal sound exposure meters of one accuracy grade. The accuracy grade corresponds
to that for an integrating sound level meter which complies with the Type 2 requirements of
IEC 60804 for an A-weighted sound pressure level range from 80 dB to 130 dB and a nominal
frequency range from 63 Hz to 8 kHz.
1.4 Tolerances on deviations of an instrument's performance from specified design goals
represent the performance capabilities of practical instruments. Personal sound exposure
meters are required to operate within the tolerances of this International Standard over
specified ranges of environmental conditions.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents listed below. Members of IEC
and ISO maintain registers of currently valid normative documents.
IEC 60050(801):1984, Advance edition of the International Electrotechnical Vocabulary,
Chapter 801, Acoustics and electroacoustics
IEC 60651:1979, Sound level meters
IEC 60801-2:1984, Electromagnetic compatibility for industrial-process measurement and
control equipment – Part 2: Electrostatic discharge requirements
IEC 60801-3:1984, Electromagnetic compatibility for industrial-process measurement and
control equipment – Part 3: Radiated electromagnetic field requirements
IEC 60804:1985, Integrating-averaging sound level meters
IEC 60942:1988, Sound calibrators

+AMD2:2017  IEC 2017
IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 2: Electrostatic discharge immunity test. Basic EMC publication
IEC 61000-4-3:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 3: Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-20:2010, Electromagnetic compatibility (EMC) – Part 4-20: Testing and
measurement techniques – Emission and immunity testing in transverse electromagnetic (TEM)
waveguides
IEC 61000-6-1:1997, Electromagnetic compatibility (EMC) – Part 6: Generic standards –
Section 1: Immunity for residential, commercial and light-industrial environments
IEC 61000-6-2:1999, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards –
Immunity for industrial environments
CISPR 22:1997, Information technology equipment – Radio disturbance characteristics – Limits
and methods of measurement
CISPR 61000-6-3:1996, Electromagnetic compatibility (EMC) – Part 6: Generic standards –
Section 3: Emission standard for residential, commercial and light-industrial environments
ISO 266:1975, Acoustics – Preferred frequencies for measurements
ISO 1683:1983, Acoustics – Preferred reference quantities for acoustic levels
ISO 1999:1990, Acoustics – Determination of occupational noise exposure and estimation of
noise-induced hearing impairment
ISO 9612:199X, Acoustics – Guidelines for the measurement and assessment of exposure to
*
noise in the working environment
3 Definitions
For the purposes of this International Standard, the following definitions apply. Definitions are
consistent with corresponding definitions in IEC 60050(801).
3.1
sound exposure
time integral of squared, instantaneous A-frequency-weighted sound pressure over a specified
event, for example, a working day
NOTE 1 Although the primary SI unit for sound exposure is the pascal-squared second, for measurements of
sound exposure in the workplace, the more-convenient derived unit, the pascal-squared hour, is used in this
International Standard.
NOTE 2 In symbols, (A-weighted) sound exposure is
t
E = p (t) d t (1)
A
∫
t
where p (t) is the square of instantaneous A-frequency-weighted sound pressure as a function of time t for an
A
integration time period starting at t and ending at t . The unit of sound exposure E is pascal-squared hours if
1 2
A-weighted sound pressure p is in pascals and the running time t in hours.
A
________
*
At present, at the stage of draft.

– 8 – IEC 61252:1993+AMD1:2000
+AMD2:2017  IEC 2017
3.2
equivalent-continuous A-weighted sound pressure level; time-average sound level
in decibels, ten times the logarithm to the base ten of the ratio of the time-mean-square,
A-frequency-weighted sound pressure, during an averaging time period T, to the square of the
standard reference sound pressure
NOTE 1 In symbols, equivalent-continuous A-weighted sound pressure level L , or time-average sound level,
Aeq,T
is given by:
T
2 2
L = 10 lg {[(1/T) p (t) d t ] / p } (2)
Aeq,T
∫ A 0
where running time t and averaging time T are expressed in the same units, p (t) is the instantaneous A-weighted
A
sound pressure in pascals, and p is the reference sound pressure of twenty micropascals (20µPa) per ISO 1683.
NOTE 2 Equivalent-continuous A-weighted sound pressure level during the averaging time period T is related to
the total sound exposure occurring within that period by
2 0,1 × L
E = (p T) [10 Aeq,T ] (3)
or, alternatively, by
L = 10 lg [E / (p T )] (4)
Aeq,T 0
where the unit of time is the same for both sound exposure and averaging time.
3.3
normalized 8-h-average sound level
in decibels, level of the time-mean-square, A-weighted sound pressure during a normalization
time period T of 8 h such that the sound exposure therefrom is equal to that of a time-varying
n
sound at a place where total sound exposure occurs within a time period not necessarily 8 h
NOTE 1 In symbols, a normalized 8-h-average sound level (letter symbol L ), relative to the reference sound
Aeq,8hn
pressure p and the 8 h normalization time period T , is given by:
0 n
L = 10 lg [E / (p T ) ] (5)
Aeq,8hn 0 n
NOTE 2 For computations, a simpler form of Eq.(5) for normalized 8-h-average sound level in decibels is
obtained, for sound exposure E in pascal-squared hours, after substituting the values of 20 micropascals for p and
8 h for T , as
n
L = 10 lg [ (E × 10 ) / 3,2] (6)
Aeq,8hn
NOTE 3 When a total sound exposure is described indirectly by an equivalent-continuous A-weighted sound
pressure level L , for an averaging time T greater or less than the normalization time period of 8 h, normalized
Aeq,T
8-h-average sound level may be determined from
L = L + 10 lg (T/T ) (7)
Aeq,8hn Aeq,T n
NOTE 4 Annex A provides a table of normalized 8-h-average sound levels and corresponding sound exposures.
For example, a sound exposure of 1 Pa h (irrespective of the period of time over which it is measured) corresponds
to a normalized 8-h-average sound level of nearly 85 dB; a sound exposure of 3,2 Pa h corresponds exactly to a
normalized 8-h-average sound level of 90 dB.
NOTE 5 Normalized 8-h-average sound level in Eq.(5) is identical to "daily personal noise exposure L in
EP,d
decibels" defined in Article 2 of the "European Communities Council Directive of 12 May 1986 on the protection of
workers from the risks related to exposure to noise at work" (Directive 86/188/EEC).
NOTE 6 Normalized 8-h-average sound level in Eq.(5) is also the same as "noise exposure level normalized to a
nominal 8 h working day, L " defined in ISO 1999.
EX,8h
3.4
sound level range
in decibels, lower and upper time-average, A-weighted sound pressure levels without
exponential time weighting, specified by the manufacturer, within which linearity requirements
of this International Standard are met
3.5
sound exposure range
range between an upper and a lower sound exposure, both to be specified by the manu-
facturer, within which the requirements of this International Standard are met and which are
displayed on the sound exposure indicator

+AMD2:2017  IEC 2017
3.6
reference direction
direction of sound incidence specified by the manufacturer for determining the absolute
acoustical sensitivity and frequency response
3.7
reference frequency
frequency of 1 kHz for determining the absolute acoustical sensitivity
3.8
reference sound pressure level
sound pressure level specified by the manufacturer for determining the absolute acoustical
sensitivity
3.9
reference integration time
integration time specified by the manufacturer for determining the absolute acoustical
sensitivity
3.10
reference sound exposure
calculated sound exposure corresponding to the reference sound pressure level, at the
reference frequency, applied for the reference integration time
The following definition applies in addition to those specified in IEC 61000-4-2, IEC 61000-4-3,
IEC 61000-6-1, IEC 61000-6-2, and CISPR 61000-6-3.
3.11
reference orientation (of a personal sound exposure meter)
orientation of a personal sound exposure meter that corresponds to the meter as worn in
normal use by a person standing upright and facing the principal direction of an emitter or
receiver of radio-frequency electromagnetic fields
4 General performance requirements
4.1 A personal sound exposure meter is a combination of a microphone, an amplifier with the
required A-frequency weighting, a device to square the frequency-weighted sound pressure
signal, an integrator over time, an indicator of sound exposure, and a latching overload
indicator. Sound exposures that have been accumulated during a measurement period are
retained in the memory until the instrument is reset and are not deleted by triggering of the
latching overload indicator.
– 10 – IEC 61252:1993+AMD1:2000
+AMD2:2017  IEC 2017
IEC  068/02
Figure 1 – Functional elements of a personal sound exposure meter
4.2 Because only its overall performance is important, an actual instrument need not be
separable into individual functional elements. However, for convenient description of required
characteristics, the instrument is considered as if it were a combination of the separate
elements shown in figure 1.
4.3 The manufacturer shall provide the means to substitute an electrical input signal in place
of the microphone, for the purpose of performing tests on the complete instrument without the
microphone.
NOTE The manufacturer may provide an accessible input test point or recommend and provide a dummy
microphone or equivalent input adapter (electrical or non-electrical) for performing electrical tests on the
instrument.
4.4 An optional (but preferred) accessible output test point may be provided.
4.5 The sound exposure indicator may be built into, or be separate from, the wearable part of
an instrument. The quantity indicated is sound exposure, either as a direct indication or as a
fraction or percentage of a manufacturer-specified sound exposure. If sound exposure is not
indicated directly in pascal-squared hours (Pa h), the manufacturer shall provide suitable
means to convert the indication to sound exposure in pascal-squared hours.
4.6 The smallest increment of sound exposure displayed by the indicator shall be not greater
2 2 2
than 0,1 Pa h. The sound exposure range shall be at least from 0,1 Pa h to 99,9 Pa h.
4.7 The sound level range shall extend at least from 80 dB to 130 dB.
4.8 The manufacturer shall state in the Instruction Manual the sound exposure range and the
sound level range.
4.9 If the manufacturer-specified ranges of sound exposure and sound level exceed the
minimum requirements of this International Standard, all specifications and associated
tolerances shall apply to the ranges stated by the manufacturer.
4.10 If the specified lower boundary of the sound level range is less than 80 dB, the lower
boundary of the sound exposure range shall be less than 0,1 Pa h.
4.11 Specifications in subsequent clauses for the acoustical and electrical performance of a
personal sound exposure meter are applicable for the reference conditions of clause 5. Clause 12
provides requirements for limits on the changes in the sensitivity of a personal sound exposure
meter when used under environmental conditions different from the reference conditions.

+AMD2:2017  IEC 2017
4.12 A power supply of the type recommended by the manufacturer shall be able to operate a
personal sound exposure meter within all specifications of this International Standard for at
least 8 h at any temperature within the range specified by the manufacturer of the personal
sound exposure meter. If a personal sound exposure meter is battery operated, the
manufacturer shall provide a method to check that the battery voltage is sufficient to operate
the instrument within the specifications at the time the check is made. A check of battery
condition shall not disturb a measurement of sound exposure.
5 Reference conditions
Reference conditions for a personal sound exposure meter are: atmospheric pressure of 101,3 kPa;
air temperature of 20 °C; relative humidity of 65 % ; and absence of significant interference caused
by ambient sounds, airflow over the microphone, vibrations, magnetic fields, electromagnetic fields,
or electrostatic fields.
NOTE Significant interference is when the effect on the indicated sound exposure exceeds ten percent of an
applicable tolerance limit.
6 Absolute acoustical sensitivity
6.1 A means shall be available for the user to check and maintain the sensitivity of a personal
sound exposure meter such that the tolerances in 6.2 for reference sound exposure are met
under the reference conditions. If this means is a sound calibrator, it shall meet the
requirements of IEC 60942.
NOTE 1 A sound calibrator meeting the Class 1 requirements of IEC 60942 is preferred.
NOTE 2 The integration time period for checking the absolute acoustical sensitivity should not exceed 2 min.
NOTE 3 If another quantity such as sound pressure level can be displayed, it may be used to check the calibration
of the instrument.
6.2 The personal sound exposure meter shall be checked and, if necessary, adjusted in
accordance with the manufacturer's instructions. Under the reference environmental conditions
of clause 5 and for plane-progressive sound waves incident on the microphone from the
reference direction, the indicated sound exposure shall be within the range –21 % to +26 % of
the reference sound exposure at the reference frequency of 1 kHz. This requirement shall
apply with the microphone of the personal sound exposure meter mounted as specified by the
manufacturer, but not mounted on a person and without an observer disturbing the sound field.
NOTE Calibration of the absolute acoustical sensitivity of a personal sound exposure meter may be carried out by
means of a closed-coupler pressure-calibration device, in conjunction with manufacturer-specified corrections for
the free-field response, applicable to the type of microphone used on the personal sound exposure meter.
7 Frequency weighting
7.1 Under the reference environmental conditions of clause 5 and for plane-progressive
sound waves incident on the microphone from the reference direction and with the reference
sound pressure level at the microphone, a complete personal sound exposure meter, with the
microphone mounted as specified by the manufacturer but not mounted on a person and
without an observer disturbing the sound field, shall have the relative A-weighting frequency
characteristic, for constant-amplitude sinusoidal signals, as specified in table 1. The design-
goal A-frequency weighting is a smooth and continuous function of frequency as specified in
IEC 60651. At each nominal frequency in table 1, the ratio of a measured sound exposure to
the sound exposure at 1 kHz shall fall within the specified sound-exposure tolerances.
At intermediate frequencies, the applicable tolerances are the wider limits determined from the
A-weighting tolerances in decibels given in table 1.

– 12 – IEC 61252:1993+AMD1:2000
+AMD2:2017  IEC 2017
Table 1 – Design-goal A-frequency weighting relative to response at 1 kHz
∆A that apply to the performance of a complete
and the tolerances
personal sound exposure meter
Nominal
A ∆A Sound exposure ratio
frequency
Hz dB dB min max
design-goal ε
63 –26,2 ±2,0 0,0015 0,0024 0,0038
125 –16,1 ±1,5 0,0174 0,0245 0,0347
250 –8,6 ±1,5 0,098 0,138 0,195
500 –3,2 ±1,5 0,339 0,479 0,676
1 k 0,0  1,000
2 k 1,2 ±2,0 0,832 1,318 2,089
4 k 1,0 ±3,0 0,631 1,259 2,512
8 k –1,1 ±5,0 0,246 0,776 2,455
NOTE 1 At frequency less than 63 Hz and greater than 8 kHz, the sensitivity of a personal sound
exposure meter should follow the standard design-goal A-weighting and the frequency response should
not exceed the positive tolerances gives in IEC 60651 for Type 2 sound level meters.
NOTE 2 It is recommended that a personal sound exposure meter should respond over a range of
frequencies extending from 31,5 Hz to 12,5 kHz. The manufacturer should state the nominal frequency
range of the instrument and the corresponding tolerances that are maintained.
NOTE 3 In use, the directional characteristics of a personal sound exposure meter are strongly affected
by the presence of the wearer of the instrument and the mounting position of the instrument or its
microphone. For those reasons, this International Standard includes no specifications for the response to
sounds from various directions.

7.2 At nominal frequencies from 63 Hz to 8 kHz, table 1 gives the design-goal A-frequency
weighting relative to sound exposure response at 1 kHz, as a relative level in decibels and as
a ratio of exposures measured with constant-amplitude, constant-duration sinusoidal signals.
Nominal frequencies are the preferred frequencies from ISO 266.
NOTE Sound exposure ratio may be calculated from the following:
The design-goal sound exposure ratio ε is given by:
0,1 A
ε = 10 (8)
sound exposure ratio max or min:
0,1(A + ∆A)
ε + ∆ε = 10 (9)
where weighting A and tolerance ∆A are in decibels.
7.3 Tolerances in decibels are given in the column headed "∆A" and are relative to the
corresponding A-frequency-weighting design-goal response. Tolerances on sound exposure
ratio given in columns headed "min" and "max" are relative to the corresponding design-goal
sound exposure ratio in the column marked ε in table 1.
7.4 Compliance with the requirements of table 1 may be demonstrated by a combination of
acoustical and electrical tests. Annex B provides recommendations for tests of frequency
weighting.
8 Linearity of response to steady signals
8.1 For steady sinusoidal signals at a frequency of 1 kHz, and for changes in sound exposure
with respect to either or both input sound pressure level and integration time, all indicated
sound exposures shall be within the range –21 % to +26 % of the calculated sound exposure.
These tolerances shall apply for any calculated sound exposure over the complete sound level
range and from three times the lower boundary of the sound exposure range up to the upper
boundary of the sound exposure range, and for integration time periods of up to 8 h.

+AMD2:2017  IEC 2017
NOTE Calculated sound exposures may be determined from Eq.(3) for given input sound levels and integration
times.
8.2 For steady sinusoidal signals at a frequency of 63 Hz, and for changes in both input
sound pressure level and integration time that yield a calculated sound exposure of 1 Pa h,
the indicated sound exposure shall be within the range –21 % to +26 % for input signals
corresponding to sound pressure levels from 120 dB (equivalent to an A-weighted sound
pressure level of 93,8 dB) up to the upper boundary of the sound level range specified by the
manufacturer for 63 Hz. For linearity of response at 63 Hz, the reference is the indicated sound
exposure, nominally 1 Pa h, for an input sound pressure level of 130 dB (equivalent to an
A-weighted sound pressure level of 103,8 dB) at 63 Hz. A reduction of the upper boundary of
the sound level range is permitted at 63 Hz, provided the reduction is specified by the
manufacturer and the reduction does not exceed the design-goal response of –26,2 dB for the
A-weighting at 63 Hz.
8.3 For steady sinusoidal signals at a frequency of 8 kHz, and for changes in both input sound
pressure level and integration time that yield a calculated sound exposure of 1 Pa h,
the indicated sound exposure shall be within the range –21 % to +26 % for input signals
corresponding to sound pressure levels from 90 dB (equivalent to an A-weighted sound
pressure level of 88,9 dB) up to 110 dB (equivalent to an A-weighted sound pressure level of
108,9 dB). The same tolerances apply when the calculated sound exposure is 50 Pa h and the
input signals correspond to sound pressure levels from 110 dB up to the upper boundary of the
sound level range. For linearity of response at 8 kHz, the reference is the indicated sound
2 2
exposure, nominally 1 Pa h and 50 Pa h, for an input sound pressure level of 110 dB at 8 kHz.
8.4 Annex B describes recommendations for tests to demonstrate compliance with the
requirements of this clause.
9 Response to short-duration signals
9.1 At a design-goal sound exposure of 1 Pa h, the indication of a personal sound exposure
meter in response to a sequence of repeated 4 kHz tonebursts shall be within specified
tolerances of the corresponding sound exposure indicated in response to a steady 4 kHz
sinusoidal signal.
9.2 The level of the steady 4 kHz reference input signal shall correspond to a nominal sound
pressure level of 94,0 dB, that is, to a nominal A-weighted sound pressure level of 95 dB.
9.3 The duration of the steady 4 kHz signal shall be such that the indicated sound exposure is
2 2
between 0,71 Pa h and 1,41 Pa h.
NOTE For the design-goal sound exposure of 1 Pa h and an A-weighted sound pressure level of 95 dB, the
duration is 47 min, 26 s.
9.4 All tonebursts shall start and stop at a zero crossing. The duration of individual tonebursts
shall be 1 ms (4 cycles) and 10 ms (40 cycles). With 1 ms duration tonebursts, the time between
tonebursts shall be 999 ms to yield a 1:1 000 ratio of burst "on time" to burst-repetition time.
With 10 ms duration tonebursts, the time between tonebursts shall be 990 ms and 9 990 ms to
yield 1:100 and 1:1 000 ratios of burst "on time" to burst-repetition time.
9.5 Sound exposures indicated in response to a sequence of repeated 1 ms and 10 ms
tonebursts meeting the requirements of 9.4 shall be within the range –21 % to +26 % of the
sound exposure indicated for the steady 4 kHz reference signal for toneburst signal levels (that
is, levels of the steady 4 kHz sinusoidal signal from which the tonebursts are extracted) up to
125 dB and within the range –29 % to +41 % of the sound exposure indicated for the steady
4 kHz reference signal for toneburst signal levels up to the upper boundary of the specified
sound level range.
– 14 – IEC 61252:1993+AMD1:2000
+AMD2:2017  IEC 2017
9.6 Annex B describes recommendations for tests to demonstrate compliance with the
requirements of this clause.
10 Response to unipolar pulses
For the same nominal integration times, the sound exposure indicated by a personal sound
exposure meter in response to a sequence of positive-going, unipolar, approximately 0,5 ms

duration pulses, separated by at least 4,5 ms, shall be within the range –21 % to +26 % of the
sound exposure indicated in response to a sequence of negative-going pulses of the same
absolute amplitude, duration, and spacing. Annex B provides a recommended procedure to test
the response to unipo
...

NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Edition 1.1
STANDARD
2002-03
Edition 1:1993 consolidée par l'amendement 1:2000
Edition 1:1993 consolidated with amendment 1:2000
Electroacoustique –
Spécifications des exposimètres
acoustiques individuels
Electroacoustics –
Specifications for personal
sound exposure meters
Numéro de référence
Reference number
CEI/IEC 61252:1993+A1:2000
Numérotation des publications Publication numbering
Depuis le 1er janvier 1997, les publications de la CEI As from 1 January 1997 all IEC publications are
sont numérotées à partir de 60000. Ainsi, la CEI 34-1 issued with a designation in the 60000 series. For
devient la CEI 60034-1. example, IEC 34-1 is now referred to as IEC 60034-1.
Editions consolidées Consolidated editions
Les versions consolidées de certaines publications de la The IEC is now publishing consolidated versions of its
CEI incorporant les amendements sont disponibles. Par publications. For example, edition numbers 1.0, 1.1
exemple, les numéros d’édition 1.0, 1.1 et 1.2 indiquent and 1.2 refer, respectively, to the base publication,
respectivement la publication de base, la publication de the base publication incorporating amendment 1 and
base incorporant l’amendement 1, et la publication de the base publication incorporating amendments 1
base incorporant les amendements 1 et 2. and 2.
Informations supplémentaires Further information on IEC publications
sur les publications de la CEI
Le contenu technique des publications de la CEI est The technical content of IEC publications is kept
constamment revu par la CEI afin qu'il reflète l'état under constant review by the IEC, thus ensuring that
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nibles dans le Catalogue des publications de la CEI available in the IEC Catalogue of publications
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NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Edition 1.1
STANDARD
2002-03
Edition 1:1993 consolidée par l'amendement 1:2000
Edition 1:1993 consolidated with amendment 1:2000
Electroacoustique –
Spécifications des exposimètres
acoustiques individuels
Electroacoustics –
Specifications for personal
sound exposure meters
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– 2 – 61252  CEI:1993+A1:2000
SOMMAIRE
AVANT-PROPOS .4
INTRODUCTION.8
1 Domaine d'application.10
2 Références normatives .10
3 Définitions .12
4 Prescriptions générales .16
5 Conditions de référence.20
6 Sensibilité acoustique absolue .20
7 Pondération fréquentielle .22
8 Linéarité de la réponse à des signaux permanents .24
9 Réponse à des signaux de courte durée.24
10 Réponse à des impulsions unipolaires.26
11 Indicateur de surcharge à verrouillage.26
12 Sensibilité aux divers environnements.28
13 Marquage de l'instrument.30
14 Notice d'Emploi.30
15 Prescriptions concernant les compatibilités électromagnétiques et électrostatiques
et procédures d’essais .34
Annexe A (informative) Expositions sonores et niveaux sonores moyens
correspondants ramenés à 8 h .46
Annexe B (informative) Essais recommandés pour la vérification des caractéristiques
d'un exposimètre acoustique individuel.48
Annexe C (informative) Limites concernant l’émission .58
Figure 1 – Eléments fonctionnels d'un exposimètre acoustique individuel.18
Tableau 1 – Pondération fréquentielle A par rapport à la réponse à 1 kHz et tolérance ΔA
sur les caractéristiques d'un exposimètre acoustique individuel complet .22
Tableau A.1 – Expositions sonores et niveaux sonores moyens
correspondants ramenés à 8 h .46
Tableau B.1 – Ensemble minimal de conditions expérimentales pour les essais
de linéarité avec un signal permanent à 1 kHz.50
Tableau B.2 – Conditions pour les essais de la réponse à des signaux de courte durée .54
Tableau C.1 – Limites des perturbations rayonnées à une distance d’essai de 10 m
pour les ATI de classe B .58

61252  IEC:1993+A1:2000 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.9
1 Scope.11
2 Normative references.11
3 Definitions .13
4 General performance requirements .17
5 Reference conditions .21
6 Absolute acoustical sensitivity.21
7 Frequency weighting .23
8 Linearity of response to steady signals.25
9 Response to short-duration signals .25
10 Response to unipolar pulses .27
11 Latching overload indicator .27
12 Sensitivity to various environments .29
13 Instrument marking.31
14 Instruction Manual .31
15 Electromagnetic and electrostatic compatibility requirements and test procedures .35
Annex A (informative) Sound exposures and corresponding normalized
8-h-average sound levels .47
Annex B (informative) Recommended tests to verify the performance
of a personal sound exposure meter.49
Annex C (informative) Emission limits .59
Figure 1 – Functional elements of a personal sound exposure meter .19
Table 1 – Design-goal A-frequency weighting relative to response at 1 kHz
and the tolerances ΔA that apply to the performance of a complete personal sound
exposure meter .23
Table A.1 – Sound exposures and corresponding normalized 8-h-average sound levels .47
Table B.1 – Minimum set of target conditions for 1 kHz steady-signal linearity tests .51
Table B.2 – Conditions for testing response to short-duration signals.55
Table C.1 – Limits for radiated disturbance of class B ITE
at a measuring distance of 10 m.59

– 4 – 61252 © CEI:1993+A1:2000
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
____________
ÉLECTROACOUSTIQUE –
SPÉCIFICATIONS DES EXPOSIMÈTRES ACOUSTIQUES INDIVIDUELS

AVANT-PROPOS
1) La CEI (Commission Electrotechnique Internationale) est une organisation mondiale de normalisation composée
de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a pour objet de
favoriser la coopération internationale pour toutes les questions de normalisation dans les domaines de
l'électricité et de l'électronique. A cet effet, la CEI, entre autres activités, publie des Normes internationales.
Leur élaboration est confiée à des comités d'études, aux travaux desquels tout Comité national intéressé par le
sujet traité peut participer. Les organisations internationales, gouvernementales et non gouvernementales, en
liaison avec la CEI, participent également aux travaux. La CEI collabore étroitement avec l'Organisation
Internationale de Normalisation (ISO), selon des conditions fixées par accord entre les deux organisations.
2) Les décisions ou accords officiels de la CEI concernant les questions techniques représentent, dans la mesure
du possible, un accord international sur les sujets étudiés, étant donné que les Comités nationaux intéressés
sont représentés dans chaque comité d’études.
3) Les documents produits se présentent sous la forme de recommandations internationales. Ils sont publiés
comme normes, spécifications techniques, rapports techniques ou guides et agréés comme tels par les Comités
nationaux.
4) Dans le but d'encourager l'unification internationale, les Comités nationaux de la CEI s'engagent à appliquer de
façon transparente, dans toute la mesure possible, les Normes internationales de la CEI dans leurs normes
nationales et régionales. Toute divergence entre la norme de la CEI et la norme nationale ou régionale
correspondante doit être indiquée en termes clairs dans cette dernière.
5) La CEI n’a fixé aucune procédure concernant le marquage comme indication d’approbation et sa responsabilité
n’est pas engagée quand un matériel est déclaré conforme à l’une de ses normes.
6) L’attention est attirée sur le fait que certains des éléments de la présente Norme internationale peuvent faire
l’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour
responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.
La Norme internationale CEI 61252 a été établie par le comité d'études 29 de la CEI:
Electroacoustique.
La présente version consolidée de la CEI 61252 comprend la première édition (1993)
[documents 29(BC)162 et 29(BC)168] et son amendement 1 (2000) [documents 29/457/FDIS
et 29/471/RVD].
Le contenu technique de cette version consolidée est donc identique à celui de l'édition de
base et à son amendement; cette version a été préparée par commodité pour l'utilisateur.
Elle porte le numéro d'édition 1.1.
Une ligne verticale dans la marge indique où la publication de base a été modifiée par
l'amendement 1.
Dans cette Norme internationale sur les exposimètres acoustiques individuels, les spécifi-
cations sont compatibles autant que possible avec les spécifications correspondantes de
la CEI 60804 sur les sonomètres intégrateurs. Les quatre principales différences techniques
par rapport aux spécifications de la CEI 60804, édition de 1985, sont:
a) l'exposition sonore est mesurée et affichée de préférence au niveau continu équivalent de
la pression acoustique pondérée en fréquence ou au niveau d'exposition sonore;
b) la précision de l'intégration du carré des signaux de courte durée est spécifiée par la
mesure de l'exposition sonore d'une suite de salves de durée 1 ms et 10 ms, d'amplitude
constante et de fréquence 4 kHz, de préférence à la mesure de la réponse à des salves
uniques de 4 kHz, d'amplitude variable avec une durée comprise entre 1 ms et 1 s, chaque
salve unique étant accompagnée par un signal de fond permanent, de faible niveau, en
phase et de fréquence 4 kHz;
61252 © IEC:1993+A1:2000 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS –
SPECIFICATIONS FOR PERSONAL SOUND EXPOSURE METERS

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61252 has been prepared by IEC technical committee 29:
Electroacoustics.
This consolidated version of IEC 61252 consists of the first edition (1993) [documents
29(CO)162 and 29(CO)168] and its amendment 1 (2000) [documents 29/457/FDIS and
29/471/RVD].
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 1.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
Specifications in this International Standard for personal sound exposure meters are
consistent, insofar as practical, with comparable specifications in IEC 60804 for integrating
sound level meters. The four principal technical differences from the specifications in the 1985
issue of IEC 60804 are:
a) sound exposure is measured and displayed rather than equivalent-continuous frequency-
weighted sound pressure level or sound exposure level;
b) accuracy of squaring and integrating short-duration signals is specified by measurement of
the sound exposure of a sequence of repeated constant-amplitude, 1 ms and 10 ms
duration, 4 kHz tonebursts rather than by measurement of the response to single 4 kHz
tonebursts of varying amplitudes with durations ranging from 1 ms to 1 s, each single
toneburst being accompanied by a continuous, in-phase, low-level, 4 kHz background
signal;
– 6 – 61252  CEI:1993+A1:2000
c) les spécifications pour un exposimètre acoustique individuel comprennent une limitation sur
la différence entre l'exposition sonore indiquée en réponse à des impulsions unipolaires de
sens positif et de sens négatif; et
d) on ne donne pas de prescriptions pour la directivité du microphone de l'exposimètre
acoustique individuel destiné à être porté par une personne.
Cette Norme internationale comporte deux annexes informatives. L'annexe A contient un
tableau d'une sélection d'expositions sonores et les niveaux sonores moyens correspondants
ramenés à 8 h. L'annexe B donne des recommandations pour les essais de vérification des
caractéristiques d'un exposimètre acoustique individuel.
Le comité a décidé que le contenu de la publication de base et de ses amendements ne sera
pas modifié avant 2004. A cette date, la publication sera
• reconduite;
• supprimée;
• remplacée par une édition révisée, ou
• amendée.
61252  IEC:1993+A1:2000 – 7 –
c) specifications for a personal sound exposure meter include a limitation on the difference
between the sound exposure indicated in response to positive-going and negative-going
unipolar pulses; and
d) requirements are not specified for the directional response of the microphone of a personal
sound exposure meter intended to be worn on a person.
This International Standard includes two informative annexes. Annex A provides a table of
selected sound exposures and corresponding normalized 8-h-average sound levels. Annex B
describes recommendations for tests to verify the performance of a personal sound exposure
meter.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until 2004. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 8 – 61252  CEI:1993+A1:2000
INTRODUCTION
Suivant cette Norme internationale, un exposimètre acoustique individuel est destiné à
mesurer l'exposition sonore qui est l'intégrale en fonction du temps du carré de la pression
acoustique instantanée pondérée A en fréquence. Ce principe de fonctionnement est à la base
de la mesure du niveau d'exposition sonore suivant la CEI 60804. C'est le «taux d'échange à
égale énergie» pour lequel un doublement (ou une division par deux) de la durée d'intégration
d'un niveau sonore permanent produit un doublement (ou une division par deux) de l'exposition
sonore. De même, une augmentation (ou une diminution) de 3 dB du niveau sonore permanent
d'entrée pour une durée d'intégration constante produit un doublement (ou une division par
deux) de l'exposition sonore.
Les dosimètres ont été généralement conçus pour indiquer la dose de bruit sous forme de
pourcentage d'une limite légale. La limite et sa définition varient d'un pays à l'autre et sont
susceptibles de changer. Afin de faciliter les comparaisons internationales entre des valeurs
numériques d'amplitude convenable des expositions sonores enregistrées, cette Norme
internationale spécifie un instrument qui indique l'exposition sonore en pascals carrés-heures.
Une indication de l'exposition sonore par une unité autre que le pascal carré-heure est permise
à condition que le constructeur spécifie une procédure pour convertir la lecture en pascals
carrés-heures, par exemple, l'affichage d'une «dose» exprimée sous forme d'une fraction ou
d'un pourcentage d'une exposition sonore spécifiée en pascals carrés-heures.
L'application principale pour un exposimètre acoustique individuel est la mesure de l'exposition
sonore à proximité de la tête d'une personne; par exemple pour l'estimation du risque de perte
d'audition selon les Normes telles que l'ISO 1999. Le microphone d'un exposimètre acoustique
individuel peut être porté sur l'épaule, le col, ou à un autre emplacement près d'une oreille.
Pour de nombreuses situations pratiques, par exemple dans les usines où l'angle d'incidence
du son peut largement varier durant le cours de la journée de travail, l'exposition sonore
indiquée par un instrument porté par une personne est probablement différente de celle qui
serait mesurée en l'absence de la personne. Il convient d'examiner l'influence de la personne
portant l'exposimètre acoustique individuel quand on estime l'exposition sonore qui aurait été
mesurée avec la personne absente.

61252  IEC:1993+A1:2000 – 9 –
INTRODUCTION
According to this International Standard, a personal sound exposure meter is intended to
measure sound exposure as the time integral of the square of the instantaneous A-frequency-
weighted sound pressure. This operating principle underlies the measurement of sound
exposure level according to IEC 60804. It is the "equal-energy exchange rate" whereby a
doubling (or halving) of the integration time of a constant sound level yields a two-fold increase
(or decrease) of sound exposure. Similarly, an increase (or decrease) of 3 dB in a constant
input sound level for a constant integration time yields a doubling (or halving) of the sound
exposure.
Noise dose meters usually have been designed to indicate noise dose as a percentage of a
legal limit. The limit and its definition vary from country to country and are subject to change.
To facilitate international comparison of sound exposure records with numerical values of
convenient magnitude, this International Standard specifies an instrument that indicates sound
exposure in pascal-squared hours. An indication of sound exposure with a unit other than
pascal-squared hours is permitted provided the manufacturer specifies a procedure for
converting the indication to pascal-squared hours, for example, a display of "dose" as a fraction
or a percentage of a specified sound exposure in pascal-squared hours.
The principal application for a personal sound exposure meter is the measurement of sound
exposure in the vicinity of a person's head; e.g., for assessment of potential hearing
impairment according to Standards such as ISO 1999. The microphone of a personal sound
exposure meter may be worn on the shoulder, collar, or other location close to one ear. For
many practical situations, such as in a factory where the sound-incidence angle may vary
widely during the course of workday, the sound exposure indicated by an instrument worn on a
person is likely to be different from that which would be measured in the absence of the
person. The influence of the person wearing a personal sound exposure meter should be
considered when estimating the sound exposure that would have been measured with the
person absent.
– 10 – 61252  CEI:1993+A1:2000
ÉLECTROACOUSTIQUE –
SPÉCIFICATIONS DES EXPOSIMÈTRES ACOUSTIQUES INDIVIDUELS
1 Domaine d'application
1.1 L'exposition sonore est une mesure physique qui tient compte à la fois de la pression
acoustique et de la durée des sons, à un emplacement donné, à l'aide d'une intégrale en
fonction du temps du carré de la pression acoustique instantanée pondérée en fréquence.
1.2 Cette Norme internationale est applicable aux instruments de mesure de l'exposition
sonore pondérée A en fréquence et résultant de sons stables, intermittents, fluctuants,
irréguliers, ou impulsifs. Les instruments satisfaisant aux spécifications de cette Norme
internationale sont destinés à être portés par une personne, pour la mesure de l'exposition
sonore. Les mesures de l'exposition sonore dans un lieu de travail peuvent être utiles pour la
détermination de l'exposition au bruit durant le travail, conformément aux Normes ISO 1999 et
ISO 9612.
1.3 Cette Norme internationale donne les prescriptions concernant les caractéristiques
acoustiques et électriques des exposimètres acoustiques individuels correspondant à une
seule classe de précision. Cette classe de précision correspond à celle d'un sonomètre
intégrateur qui satisfait aux prescriptions des instruments de classe 2 de la CEI 60804 pour un
domaine de niveaux de pression acoustique pondérée A compris entre 80 dB et 130 dB et pour
un domaine de fréquences compris entre 63 Hz et 8 kHz.
1.4 Les tolérances concernant les écarts des caractéristiques d'un instrument par rapport aux
valeurs spécifiées s'appliquent aux possibilités de l'instrument dans la pratique d'utilisation.
Les exposimètres acoustiques individuels doivent fonctionner à l'intérieur des tolérances de
cette Norme internationale dans l'étendue des domaines spécifiés pour les conditions
d'environnement.
2 Références normatives
Les documents normatifs suivants contiennent des dispositions qui, par suite de la référence
qui en est faite, constituent des dispositions valables pour la présente Norme internationale.
Au moment de la publication, les éditions indiquées étaient en vigueur. Tout document normatif
est sujet à révision et les parties prenantes des accords fondés sur cette Norme internationale
sont invitées à rechercher la possibilité d'appliquer les éditions les plus récentes des
documents normatifs cités ci-après. Les membres de la CEI et de l'ISO possèdent le registre
des documents normatifs en vigeur à un moment donné.
CEI 60050(801):1984, Edition anticipée du Vocabulaire Electrotechnique International, Chapitre 801,
Acoustique et électroacoustique
CEI 60651:1979, Sonomètres
CEI 60801-2:1984, Compatibilité électromagnétique pour les matériels de mesure et de
commande dans les processus industriels – Deuxième partie: Prescriptions relatives aux
décharges électrostatiques
CEI 60801-3:1984, Compatibilité électromagnétique pour les matériels de mesure et de
commande dans les processus industriels – Partie 3: Prescriptions relatives aux champs de
rayonnements électromagnétiques

61252  IEC:1993+A1:2000 – 11 –
ELECTROACOUSTICS –
SPECIFICATIONS FOR PERSONAL SOUND EXPOSURE METERS
1 Scope
1.1 Sound exposure is a physical measure that accounts for both the sound pressure and its
duration, at a given location, through an integral-over-time of the square of instantaneous
frequency-weighted sound pressure.
1.2 This International Standard is applicable to instruments for measurement of A-frequency-
weighted sound exposure resulting from steady, intermittent, fluctuating, irregular, or impulsive
sounds. Instruments complying with the specifications of this International Standard are
intended to be worn on a person to measure sound exposure. Measurements of sound
exposure in the workplace may be useful for determinations of occupational noise exposure, in
accordance with ISO 1999 and ISO 9612.
1.3 This International Standard specifies acoustical and electrical performance requirements
for personal sound exposure meters of one accuracy grade. The accuracy grade corresponds
to that for an integrating sound level meter which complies with the Type 2 requirements of
IEC 60804 for an A-weighted sound pressure level range from 80 dB to 130 dB and a nominal
frequency range from 63 Hz to 8 kHz.
1.4 Tolerances on deviations of an instrument's performance from specified design goals
represent the performance capabilities of practical instruments. Personal sound exposure
meters are required to operate within the tolerances of this International Standard over
specified ranges of environmental conditions.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents listed below. Members of IEC
and ISO maintain registers of currently valid normative documents.
IEC 60050(801):1984, Advance edition of the International Electrotechnical Vocabulary,
Chapter 801, Acoustics and electroacoustics
IEC 60651:1979, Sound level meters
IEC 60801-2:1984, Electromagnetic compatibility for industrial-process measurement and
control equipment – Part 2: Electrostatic discharge requirements
IEC 60801-3:1984, Electromagnetic compatibility for industrial-process measurement and
control equipment – Part 3: Radiated electromagnetic field requirements

– 12 – 61252  CEI:1993+A1:2000
CEI 60804:1985, Sonomètres intégrateurs-moyenneurs
CEI 60942:1988, Calibreurs acoustiques
CEI 61000-4-2:1995, Compatibilité électromagnétique (CEM) – Partie 4: Techniques d'essai et
de mesure – Section 2: Essai d'immunité aux décharges électrostatiques. Publication
fondamentale en CEM
CEI 61000-4-3:1995, Compatibilité électromagnétique (CEM) – Partie 4: Techniques d'essai et
de mesure – Section 3: Essai d'immunité aux champs électromagnétiques rayonnés aux
fréquences radioélectriques
CEI 61000-6-1:1997, Compatibilité électromagnétique (CEM) – Partie 6: Normes génériques –
Section 1: Immunité pour les environnements résidentiels, commerciaux et de l’industrie légère
CEI 61000-6-2:1999, Compatibilité électromagnétique (CEM) – Partie 6-2: Normes génériques –
Immunité pour les environnements industriels
CISPR 22:1997, Appareils de traitement de l’information – Caractéristiques des perturbations
radioélectriques – Limites et méthodes de mesure
CISPR 61000-6-3:1996, Compatibilité électromagnétique (CEM) – Partie 6: Normes génériques –
Section 3: Norme sur l’émission pour les environnements résidentiels, commerciaux et de
l’industrie légère
ISO 266:1975, Acoustique – Fréquences normales pour les mesurages
ISO 1683:1983, Acoustique – Grandeurs normales de référence pour les niveaux acoustiques
ISO 1999:1990, Acoustique – Détermination de l'exposition au bruit en milieu professionnel et
estimation du dommage auditif induit par le bruit
ISO 9612:199X, Acoustique – Lignes directrices pour la mesure et l'évaluation de l'exposition
*
au bruit dans un environnement de travail
3 Définitions
Pour les besoins de la présente Norme internationale, les définitions suivantes sont
applicables. Ces définitions sont compatibles avec les définitions correspondantes de la
CEI 60050(801).
3.1
exposition sonore
intégrale en fonction du temps du carré de la pression acoustique instantanée pondérée A en
fréquence pendant un événement specifié, par exemple, une journée de travail
NOTE 1 Bien que l'unité SI de l'exposition sonore soit le pascal carré-seconde, pour les mesures de l'exposition
sonore au poste de travail, l'unité dérivée plus convenable, le pascal carré-heure, est utilisée dans cette Norme
internationale.
NOTE 2 En symboles, l'exposition sonore (pondérée A) est donnée par:
t
E = p (t) d t (1)
A
∫
t
où p (t) est le carré de la pression acoustique instantanée pondérée A en fréquence, intégrée en fonction du
A
temps t, pour une durée d'intégration commençant à t et finissant à t . L'unité de l'exposition sonore E est
1 2
le pascal-carré heure si la pression acoustique pondérée p est en pascals et le temps écoulé t en heures.
A
________
*
Actuellement, au stade de projet.

61252  IEC:1993+A1:2000 – 13 –
IEC 60804:1985, Integrating-averaging sound level meters
IEC 60942:1988, Sound calibrators
IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 2: Electrostatic discharge immunity test. Basic EMC publication
IEC 61000-4-3:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 3: Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-6-1:1997, Electromagnetic compatibility (EMC) – Part 6: Generic standards –
Section 1: Immunity for residential, commercial and light-industrial environments
IEC 61000-6-2:1999, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards –
Immunity for industrial environments
CISPR 22:1997, Information technology equipment – Radio disturbance characteristics – Limits
and methods of measurement
CISPR 61000-6-3:1996, Electromagnetic compatibility (EMC) – Part 6: Generic standards –
Section 3: Emission standard for residential, commercial and light-industrial environments
ISO 266:1975, Acoustics – Preferred frequencies for measurements
ISO 1683:1983, Acoustics – Preferred reference quantities for acoustic levels
ISO 1999:1990, Acoustics – Determination of occupational noise exposure and estimation of
noise-induced hearing impairment
ISO 9612:199X, Acoustics – Guidelines for the measurement and assessment of exposure to
*
noise in the working environment
3 Definitions
For the purposes of this International Standard, the following definitions apply. Definitions are
consistent with corresponding definitions in IEC 60050(801).
3.1
sound exposure
time integral of squared, instantaneous A-frequency-weighted sound pressure over a specified
event, for example, a working day
NOTE 1 Although the primary SI unit for sound exposure is the pascal-squared second, for measurements of
sound exposure in the workplace, the more-convenient derived unit, the pascal-squared hour, is used in this
International Standard.
NOTE 2 In symbols, (A-weighted) sound exposure is
t
E = p (t) d t (1)
A
∫
t
where p (t) is the square of instantaneous A-frequency-weighted sound pressure as a function of time t for an
A
integration time period starting at t and ending at t . The unit of sound exposure E is pascal-squared hours if
1 2
A-weighted sound pressure p is in pascals and the running time t in hours.
A
________
*
At present, at the stage of draft.

– 14 – 61252  CEI:1993+A1:2000
3.2
niveau continu équivalent de pression acoustique pondérée A; niveau sonore moyen
dix fois le logarithme décimal du rapport de la moyenne quadratique, pour une durée
d'intégration T, de la pression acoustique pondérée A en fréquence au carré de la pression
acoustique de référence. Il est exprimé en décibels
NOTE 1 En symboles, le niveau L continu équivalent de pression acoustique pondérée A, ou niveau sonore
Aeq,T
moyen, est donné par:
T
2 2
L = 10 lg {[(1/T) p (t) d t ] / p}(2)
Aeq,T
A 0
∫
où le temps écoulé t et la durée d'intégration T sont exprimés dans la même unité, p (t) est la pression acoustique
A
instantanée pondérée A en pascals, et p est la pression acoustique de référence égale à vingt micropascals
(20
µPa) suivant ISO 1683.
NOTE 2 Le niveau continu équivalent de la pression acoustique pondérée A pendant la durée d'intégration T est
relié à l'exposition sonore totale produite dans cette durée par
2 0,1 × L
E = (p T) [10 Aeq,T ](3)
ou, réciproquement, par
L = 10 lg [E / (p T )] (4)
Aeq,T 0
où l'unité de temps est la même pour l'exposition sonore et la durée d'intégration.
3.3
niveau sonore moyen ramené à 8 h
niveau, exprimé en décibels, de la moyenne quadratique pour une durée normalisée T de 8 h
n
de la pression acoustique pondérée A, telle que l'exposition sonore qui en résulte soit égale à
celle d'un son variable dans le temps à un emplacement où l'exposition sonore totale
correspond à une durée qui n'est pas nécessairement égale à 8 h
NOTE 1 En symboles, le niveau sonore moyen ramené à 8 h, (symbole en lettres L ), par rapport à la
Aeq,8hn
pression acoustique de référence T
p et à la durée normalisée à 8 h, est donné par
0 n
L = 10 lg [E / (p T ) ] (5)
Aeq,8hn 0 n
NOTE 2 Pour les calculs, une forme plus simple de Eq.(5) du niveau sonore moyen ramené à 8 h en décibels est
obtenue, pour l'exposition sonore E en pascals carrés-heures, après le remplacement de p par 20 micropascals et
de T par 8 h, sous la forme:
n
L = 10 lg [ (E × 10 ) / 3,2] (6)
Aeq,8hn
NOTE 3 Quand une exposition sonore totale est exprimée indirectement par un niveau continu équivalent L de
Aeq,T
la pression acoustique pondérée A, où la durée d'intégration T est plus grande ou plus petite que la durée
normalisée de 8 h, le niveau sonore moyen ramené à 8 h peut être déterminé à partir de
L = L + 10 lg (T/T)(7)
Aeq,8hn Aeq,T n
NOTE 4 L'annexe A fournit un tableau de niveaux sonores moyens ramenés à 8 h et les expositions sonores
correspondantes. Par exemple, une exposition sonore de 1 Pa h (quel que soit l'intervalle de temps sur lequel elle
est mesurée) correspond à un niveau sonore moyen ramené à 8 h légèrement inférieur à 85 dB; une exposition
sonore de 3,2 Pa h correspond exactement à un niveau sonore moyen ramené à 8 h de 90 dB.
NOTE 5 Le niveau sonore moyen ramené à 8 h de Eq.(5) est identique à «l'exposition au bruit quotidienne
personnelle d'un travailleur L en décibels», définie dans l'Article 2 de la Directive du 12 mai 1986 de
EP,d
«l'Assemblée de la Communauté Européenne sur la protection des travailleurs contre les risques associés à
l'exposition au bruit pendant le travail» (Directive: 86/188/CEE).
NOTE 6 Le niveau sonore moyen ramené à 8 h de Eq.(5) est aussi le même que «niveau d'exposition sonore
ramené à la durée nominale de 8 h d'une journée de travail, L », défini dans ISO 1999.
EX,8h
3.4
domaine des niveaux sonores
niveaux inférieur et supérieur, exprimés en décibels, de la valeur moyenne quadratique
intégrée dans le temps sans pondération temporelle exponentielle, de la pression acoustique
pondérée A, spécifiés par le constructeur, à l'intérieur desquels les prescriptions de cette
Norme internationale sur la linéarité sont satisfaites

61252  IEC:1993+A1:2000 – 15 –
3.2
equivalent-continuous A-weighted sound pressure level; time-average sound level
in decibels, ten times the logarithm to the base ten of the ratio of the time-mean-square,
A-frequency-weighted sound pressure, during an averaging time period T, to the square of the
standard reference sound pressure
NOTE 1 In symbols, equivalent-continuous A-weighted sound pressure level L , or time-average sound level,
Aeq,T
is given by:
T
2 2
L = 10 lg {[(1/T) p (t) d t ] / p}(2)
Aeq,T
A 0
∫
where running time t and averaging time T are expressed in the same units, p (t) is the instantaneous A-weighted
A
sound pressure in pascals, and p is the reference sound pressure of twenty micropascals (20€μPa) per ISO 1683.
NOTE 2 Equivalent-continuous A-weighted sound pressure level during the averaging time period T is related to
the total sound exposure occurring within that period by
2 0,1 × L
E = (p T) [10 Aeq,T ](3)
or, alternatively, by
L = 10 lg [E / (p T )] (4)
Aeq,T 0
where the unit of time is the same for both sound exposure and averaging time.
3.3
normalized 8-h-average sound level
in decibels, level of the time-mean-square, A-weighted sound pressure during a normalization
time period T of 8 h such that the sound exposure therefrom is equal to that of a time-varying
n
sound at a place where total sound exposure occurs within a time period not necessarily 8 h
NOTE 1 In symbols, a normalized 8-h-average sound level (letter symbol L ), relative to the reference sound
Aeq,8hn
pressure p and the 8 h normalization time period T , is given by:
0 n
L = 10 lg [E / (p T ) ] (5)
Aeq,8hn 0 n
NOTE 2 For computations, a simpler form of Eq.(5) for normalized 8-h-average sound level in decibels is
obtained, for sound exposure
E in pascal-squared hours, after substituting the values of 20 micropascals for p and
8 h for T , as
n
L = 10 lg [ (E × 10 ) / 3,2] (6)
Aeq,8hn
NOTE 3 When a total sound exposure is described indirectly by an equivalent-continuous A-weighted sound
pressure level L , for an averaging time T greater or less than the normalization time period of 8 h, normalized
Aeq,T
8-h-average sound level may be determined from
L = L + 10 lg (
...