IEC 62311:2007

IEC 62311
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Assessment of electronic and electrical equipment related to human exposure
restrictions for electromagnetic fields (0 Hz – 300 GHz)

Evaluation des équipements électroniques et électriques en relation avec
les restrictions d'exposition humaine aux champs électromagnétiques
(0 Hz – 300 GHz)
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IEC 62311
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Assessment of electronic and electrical equipment related to human exposure
restrictions for electromagnetic fields (0 Hz – 300 GHz)

Evaluation des équipements électroniques et électriques en relation avec
les restrictions d'exposition humaine aux champs électromagnétiques
(0 Hz – 300 GHz)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 97.030 ISBN 2-8318-9269-4
– 2 – 62311 © IEC:2007
CONTENTS
FOREWORD.4

1 Scope and object.6

2 Normative references .6

3 Terms and definitions .6

4 Compliance criteria.10

5 Assessment methods .10

6 Evaluation of compliance to limits.11
7 Applicability of compliance assessment methods.12
7.1 General .12
7.2 Generic procedure for assessment of equipment .14
8 Sources with multiple frequencies .17
8.1 Introduction .17
8.2 Frequency range from 1 Hz – 10 MHz (ICNIRP-based).17
8.2.1 Frequency domain assessment.17
8.2.2 Time domain assessment .19
8.3 Frequency range from 100 kHz – 300 GHz (ICNIRP-based) .21
8.4 Frequency range from 0 kHz – 5 MHz (IEEE-based).22
8.4.1 Frequency domain assessment.22
8.4.2 Time domain assessment .22
8.5 Frequency range from 3 kHz – 300 GHz (IEEE-based) .23
9 Assessment report.23
9.1 General .23
9.2 Items to be recorded in the assessment report .24
9.2.1 Assessment method .24
9.2.2 Presentation of the results.24
9.2.3 Equipment using external antennas .24
10 Information to be supplied with the equipment .24

Annex A (informative) Field calculation .25
Annex B (informative) SAR compliance assessment .30

Annex C (informative) Information for numerical modelling.32
Annex D (informative) Measurements of physical properties and body currents .61
Annex E (informative) Specific absorption rate (SAR) .65
Annex F (informative) Measurement of E and H field.67
Annex G (informative)  Source modelling .70

Bibliography.73

Figure 1 – Assessment flowchart .16
Figure 2 – Schematic of “weighting circuit”.19
Figure 3 – Dependency on frequency of the reference levels V plotted with smoothing
edges .19
Figure 4 – Transfer function A.20

62311 © IEC:2007 – 3 –
Figure A.1 – Geometry of antenna with largest linear dimension D.25

Figure A.2 – Current element Idlsin(ω t) at the origin of spherical coordinate system .26

2 2
Figure A.3 – Ratio of E , H , and E × H field components .27

Figure A.4 – Ratio of E × H field components for three typical antennas.28

Figure A.5 – Far-field = straight line, radiated near-field = lower line & all near-fields =
other line .

Figure C.1 – Numerical model of a homogenous ellipsoid .34

Figure C.2 – Numerical model of a homogenous cuboid.35

Figure C.3a — Description of the whole body .36

Figure C.3b — Details of the construction of the head and shoulders.37
Figure C.3 – Numerical model of a homogenous human body .37
Figure C.4 – Schematic of straight wire.41
Figure C.5 – Schematic of circular coil.42
Figure C.6 – Block diagram of the method .43
Figure C.7 – Test situation for validation – Current loop in front of a cuboid.45
Figure C.8 – Distribution of the electric current density J in the planes x = + 0,20 m
(left) and y = 0,0 m (right) .46
Figure C.9 – Helmholtz coils and prolate spheroid .47
Figure C.10a – Magnetic field .47
Figure C.10b – Induced current density .48
Figure C.10 – Modelling results for a 60 cm by 30 cm prolate spheroid .48
Figure C.11 – Induced current density .48
Figure C.12a – Magnetic field .49
Figure C.12b – Induced current density .49
Figure C.12 – Modelling results for a 160 cm by 80 cm prolate spheroid .49
Figure C.13 – Distribution of induced electric current density.50
Figure C.14 – Schematic position of source Q against model K.51
Figure C.15 – Position of source Q, sensor and model K.52
Figure C.16 – Hot spot.54
Figure C.17 – Gradient of flux density and area G.55
Figure C.18 – Equivalent coil .55

Figure C.19 – Gradients of flux density and coil .56
Figure C.20 – Measurement distance and related distances.58

Table 1 – Characteristics and parameters of the equipment to be considered .13
Table 2 – List of possible assessment methods .14
Table B.1 – Determining whole-body SAR implicit compliance levels .30
Table C.1 – Conductivity of tissue types .38
Table C.2 – Relative permittivity of tissue types .40
Table C.3 – Summary of results.50
Table C.4 – Values G[m] of different coils with radius r and distance d .56
coil coil
A/m
⎡⎤
Table C.5 – Coupling factor k at 50 Hz for the whole body.57
T
⎣⎦
– 4 – 62311 © IEC:2007
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
ASSESSMENT OF ELECTRONIC AND ELECTRICAL EQUIPMENT

RELATED TO HUMAN EXPOSURE RESTRICTIONS

FOR ELECTROMAGNETIC FIELDS (0 Hz – 300 GHz)

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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agreement between the two organizations.
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62311 has been prepared by IEC technical committee 106:
Methods for the assessment of electric, magnetic and electromagnetic fields associated with

human exposure.
The text of this standard is based on the following documents:
FDIS Report on voting
106/129/FDIS 106/134/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

62311 © IEC:2007 – 5 –
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
– 6 – 62311 © IEC:2007
ASSESSMENT OF ELECTRONIC AND ELECTRICAL EQUIPMENT

RELATED TO HUMAN EXPOSURE RESTRICTIONS

FOR ELECTROMAGNETIC FIELDS (0 Hz – 300 GHz)

1 Scope and object
This International Standard applies to electronic and electrical equipment for which no

dedicated product- or product family standard regarding human exposure to electromagnetic
fields applies.
The frequency range covered is 0 Hz to 300 GHz.
The object of this generic standard is to provide assessment methods and criteria to evaluate
such equipment against basic restrictions or reference levels on exposure of the general
public related to electric, magnetic and electromagnetic fields and induced and contact
current.
NOTE This standard is intended to cover both intentional and non-intentional radiators. If the equipment complies
with the requirements in another relevant standard, e.g. EN 50371 covering low power equipment, then the
requirements of this standard (IEC 62311) are considered to be met and the application of this standard to that
equipment is not necessary. See also Clause 7.2.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60050-161, International Electrotechnical Vocabulary – Chapter 161: Electromagnetic
compatibility
3 Terms and definitions
For the purposes of this document, the terms and definitions contained in IEC 60050-161 as
well as the following terms and definitions apply.
3.1
averaging time
t
avg
appropriate time over which exposure is averaged for purposes of determining compliance
3.2
basic restriction
maximum exposure level that should not be exceeded under any conditions
1)
NOTE Examples of basic restrictions can be found in Annex II of the Council Recommendation 1999/519/EC [6] ,
ICNIRP Guidelines [1] IEEE Std C95.6™ [2] and IEEE Std C95.1™ [3].
———————
1)
Figures in square brackets refer to the Bibliography.

62311 © IEC:2007 – 7 –
3.3
contact current
current flowing into the body resulting from contact with a conductive object in an

electromagnetic field. This is the localised current flow into the body (usually the hand, for a

light brushing contact)
3.4
current density
J
current per unit cross-sectional area flowing inside the human body as a result of exposure to
electromagnetic fields
3.5
duty factor
duty cycle
ratio of pulse duration to the pulse period of a periodic pulse train. Also, a measure of the
temporal transmission characteristic of an intermittently transmitting RF source such as a
paging antenna by dividing average transmission duration by the average period for
transmissions. A duty factor of 1,0 corresponds to continuous operation
3.6
electric field strength
E
magnitude of a field vector at a point that represents the force (F) on an infinitely small charge
(q) divided by the charge
F
E =
q
3.7
equipment under test
EUT
an electrical or electronic apparatus that is tested for compliance with exposure limits
3.8
exposure
exposure occurs whenever and wherever a person is subjected to electric, magnetic or
electromagnetic fields or to contact current other than those originating from physiological
processes in the body and other natural phenomena
3.9
exposure level
value of the quantity used to assess exposure
NOTE This may be an induced current density, SAR, power density, electric or magnetic field strength, a limb
current or a contact current.
3.10
exposure limit
value of an electric, magnetic or electromagnetic field derived from the basic restrictions using
worst-case assumption about exposure. If the exposure limit is not exceeded, then the basic
restrictions will never be exceeded
3.11
exposure, direct effect of
result of a direct interaction in the exposed human body from exposure to electromagnetic
fields
– 8 – 62311 © IEC:2007
3.12
exposure, indirect effect of
result of a secondary interaction between the exposed human body and an electromagnetic

field, often used to describe a contact current, shock or burn arising from contact with a

conductive object
3.13
exposure, partial-body
localised exposure of part of the body, producing a corresponding localised SAR or induced

current density, as distinct from a whole-body exposure

3.14
exposure, whole-body
exposure of the whole body (or the torso when induced current density is considered)
3.15
induced current
current induced inside the body as a result of exposure to electromagnetic fields
3.16
limb current
current flowing in an arm or a leg, either as a result of a contact current or else induced by an
external field
3.17
magnetic field strength
H
magnitude of a field vector in a point that results in a force (F) on a charge (q) moving with
velocity (v)
F = q()ν × μ H
(or magnetic flux density divided by permeability of the medium, see 3.18 “magnetic flux
density”)
3.18
magnetic flux density
B
magnitude of a field vector that is equal to the magnetic field H multiplied by the permeability
(µ) of the medium
B = μH
3.19
multiple frequency fields
superposition of two or more electromagnetic fields of differing frequency.
NOTE These may be from different sources within a device, e.g., the magnetron and the transformer of a
microwave oven, or they may be harmonics in the field of a nominally single frequency source such as a
transformer
3.20
power density
S
power per unit area normal to the direction of electromagnetic wave propagation. For plane
waves the power density (S), electric field strength (E) and magnetic field strength (H) are
related by the impedance of free space, i.e., 377 Ω

62311 © IEC:2007 – 9 –
E
S = = 377 H = EH
NOTE 1 Although many survey instruments indicate power density units, the actual quantities measured are E or
H or the square of those quantities.

E and H are expressed in units of V/m and A/m, respectively, and S in the unit of W/m .

NOTE 2 It should be noted that the value of 377 Ω is only valid for free space, far field measurement conditions.

3.21
power density, average (temporal)

instantaneous power density integrated over a source repetition period. This averaging is not
to be confused with the measurement averaging time
3.22
power density, plane-wave equivalent
commonly used term associated with any electromagnetic wave, equal in magnitude to the
power density of a plane wave having the same electric (E) or magnetic (H) field strength as
the measured field
3.23
reference levels
levels of field strength or power density derived from the basic restrictions using worst-case
assumptions about exposure. If the reference levels are met, then the basic restrictions will
be complied with, but if the reference levels are exceeded, that does not necessarily mean
that the basic restrictions will not be met
3.24
root-mean-square
r.m.s.
the effective value or the value associated with joule heating, of a periodic electromagnetic
wave. The r.m.s. value is obtained by taking the square root of the mean of the squared value
of a function
T
*
F = ()F(t) ⋅ F(t) dt (expression in time domain)
∫
T
−T
n
X = ()X (expression in frequency domain)
∑ n
NOTE Although many survey instruments in the high frequency range indicate r.m.s., the actual quantity
measured is root-sum-square (rss) (equivalent field strength).
3.25
root-sum-square
rss
the value rss is obtained from three individual r.m.s. field strength values, measured in three
orthogonal directions, combined disregarding the phases.
2 2 2
X = X + X + X
x y z
– 10 – 62311 © IEC:2007
3.26
specific absorption
SA
energy absorbed per unit mass of biological tissue, expressed in joule per kilogram (J/kg);

specific energy absorption is the time integral of specific energy absorption rate

3.27
specific absorption rate
SAR
power absorbed by (dissipated in) an incremental mass contained in a volume element of
biological tissue when exposure to an electromagnetic field occurs. SAR is expressed in the
unit watt per kilogram (W/kg). SAR is used as a measure of whole-body exposure as well as

localised exposure
3.28 exposure assessment
for purposes of this standard the term exposure assessment means conformity assessment
with respect to applicable exposure limit(s).
4 Compliance criteria
Reference levels (e.g., maximum permissible exposure values, investigation levels) for public
exposure to electric, magnetic and electromagnetic fields are derived from the basic
restrictions using realistic worst-case assumptions about exposure. If the reference levels are
met, then the basic restrictions will also be met; if the reference levels are exceeded, that
does not necessarily mean that the basic restrictions are exceeded. In some situations, it may
be possible to show compliance with the basic restrictions directly. It may also be possible to
derive compliance criteria that allow a simple measurement or calculation to demonstrate
compliance with the basic restriction. Often these compliance criteria can be derived using
realistic assumptions about conditions under which exposures from a device may occur,
rather than the conservative assumptions that are the basis for the reference levels.
NOTE The limit is the basic restriction.
If the technology in the equipment is not capable of producing at the normal user position, an
E-field, H-field or contact current at levels higher than the reference levels, e.g. there are no
conductive touchable parts or the conductive touchable parts are permanently connected to
ground, then the equipment is deemed to comply with the requirements in this standard in
respect of that E-field, H-field or contact current without further assessment.
5 Assessment methods
One or more of the examples of assessment methods in 7.2 may be used.
The assessments should be made according to an existing basic standard. If the assessment
method in the basic standard is not fully applicable then deviations are allowed as long as
– a description of the assessment method used is given in the assessment report;
– an evaluation of the total uncertainty is given in the assessment report.
For transmitters intended for use with external antennas at least one typical combination of
transmitter and antenna shall be assessed. The technical specification (under far field
conditions) of this antenna shall be documented in detail such that the boundary where the
basic restrictions are met can be identified, e.g., by documented radiation patterns.
For non-radio transmitting apparatus, the compliance assessment to emissions of E or H field
has to be made according to the highest internal frequency used within the apparatus under
analysis or at which the apparatus operates with the following criteria:

62311 © IEC:2007 – 11 –
– if the highest internal frequency of the apparatus is less than 100 MHz, the assessments

shall only be made up to 1 GHz;

– if the highest internal frequency of the apparatus is between 100 MHz and 400 MHz, the

assessment shall only be made up to 2 GHz;

– if the highest internal frequency of the apparatus is between 400 MHz and 1 GHz, the
assessment shall only be made up to 5 GHz.

If the highest internal frequency of the apparatus is above 1 GHz, the measurement shall be

made up to 5 times the highest frequency.

6 Evaluation of compliance to limits
The apparatus is deemed to fulfill the requirements of this standard if the measured values
are less than or equal to the limit and if the actual assessment uncertainty is less than the
maximum measurement uncertainty specified for the applied assessment method(s). The
assessment uncertainty of assessment method shall be determined by calculating the
expanded uncertainty using a confidence interval of 95 %.
Generally, a relative uncertainty of 30 % is used for a number of EMF assessment methods.
Therefore this level of relative uncertainty is used as a default maximum in this generic
standard.
If the relative uncertainty is less than 30 %, then the measured value L shall be compared
m
directly with the applicable limit L for evaluation of compliance.
lim
If the relative uncertainty is larger than 30 %, then the actual uncertainty shall be included in
the evaluation of compliance with the limit as follows.
If the actual assessment uncertainty is larger than the specified maximum allowed uncertainty
value and if it is also larger than the maximum default uncertainty value of 30 %, then a
penalty value shall be added to the assessment result before comparison with the limit.
Conversely, one can also reduce the applicable limit L with the same penalty value, and
lim
compare the actual measured L value with the reduced limit. The right-hand side of
m
Equation 1 shows how the limit L is reduced in case the actual relative uncertainty is larger
lim
then 30 %.
NOTE The uncertainty of EMF assessment methods is generally given in %. If the uncertainty is stated in non-
linear units e.g. in dBs, then this value shall be converted into percentage (%) first.
Equation 1 shall be used to determine whether the measured value L complies with reduced
m
limit if the actual measurement uncertainty of the applicable assessment method is 30 % or
more.
⎛ ⎞
⎜ ⎟
⎜ ⎟
L ≤ L (1)
m lim
⎜ ⎟
U()L
m
⎜ ⎟
0,7 +
⎜ ⎟
L
⎝ m ⎠
where
L is the measured value;
m
L is the exposure limit;
lim
U(L ) is the absolute expanded uncertainty.
m
EXAMPLE:
Suppose the relative uncertainty of a certain EMF assessment method is 55 %. Then

– 12 – 62311 © IEC:2007
U()L
m
= 0,55
L
m
Using Equation (1), the acceptance criterion for the measured value is then:

⎛ ⎞
⎜ ⎟
1 ⎛ 1 ⎞ 1
⎜ ⎟
L ≤ L =⎜ ⎟ L = L = 0,8 L
m lim lim lim lim
⎜ ⎟
U(L )
0,7 + 0,55 1,25
⎝ ⎠
m
⎜ 0,7 + ⎟
⎜ ⎟
L
m
⎝ ⎠
The uncertainty penalty (the amount of reduction of the limit) is then:
U = L − 0,8 L = 0,2 L
pen lim lim lim
The uncertainty values specified for each EMF assessment method are the maximum allowed
uncertainties. If the uncertainty value is not specified, then a default value of 30 % shall be
used.
NOTE Guidance on the uncertainty can be found in ANSI NCSL Z540-2 [8]: US guide to the expression of
uncertainty in measurement and in the ISO/IEC Guide on Measurement Uncertainty [9].

7 Applicability of compliance assessment methods
7.1 General
An analysis can be made to investigate which parts emit EMF. A description of the several
parts of an equipment is recommended in order to determine what parts are emitting EMF.
Table 1 gives the characteristics and parameters of the equipment to be considered. Table 2
gives a list of possible assessment methods.

62311 © IEC:2007 – 13 –
Table 1 – Characteristics and parameters of the equipment to be considered

Information needed Further detailed description of the information needed

Frequency Frequency of emissions

Waveform Waveform and other information such as duty factor for establishment of peak-
and/or average emission
Multiple frequency sources Does the equipment produce fields at more than one frequency or fields with a
high harmonic content?
Are the emissions simultaneous?

Emission of electric fields Voltage differences and any coupling parts e.g., metallic surfaces charged at a

voltage potential
Emission of magnetic fields Current flow and any coupling parts e.g., coils, transducers or loops
Emission of electromagnetic fields Generation or transmission of high frequency signals and any radiating parts
e.g., antennas, loops, transducers and external cables
Contact currents Possibility of touching conducting surfaces when either the surface or the
person is exposed to electromagnetic fields?
Whole body exposure Fields produced by equipment extend over region occupied by the whole body
Partial body exposure Fields produced by equipment extend over only part of region occupied by the
body, or over region occupied by limbs
Duration/time variation Duty cycle of emissions, on/off time of power used or emitted by equipment.
Variation of power use or emissions during production process
Homogeneity Extent to which the strength of the fields varies over the body or region of the
body that is exposed. Shall be measured without the presence of a body
Far/near field Are exposures in near field? (see Annex A)
Propagating near field?
Far field?
Pulsed/transient fields Are the emissions pulse-modulated or true pulses?
Are there occasional or periodic transients in the field?
Information needed Further detailed description of the information needed
Physical size Is the equipment so small that any significant exposure will be to part of the
body?
In relation to the wavelength (operating frequency)
Is it so big that different parts will contribute to exposures “independently”?
Power What is the emitted power?
What is the power consumption?
If there is an antenna system, what is the effective radiated power?
Distance (source to user) What is the spatial relationship between the equipment and the operator or user

when it is used normally? The distance used for the assessment shall be
specified by the manufacturer and be consistent with the intended usage of the
equipment
Intended usage How is the equipment commonly used?

Conditions of intended usage producing the highest emission or absorption?
Operating conditions?
How does the intended usage affect the spatial relationship between the
equipment and the user?
Can the usage affect the emission characteristics of the equipment?
Can the equipment be part of a system?
Interaction sources/user Do the emitted fields change if the equipment is close to the body? Does the
equipment couple to the body during use?

– 14 – 62311 © IEC:2007
Table 2 – List of possible assessment methods

Assessment methods Applicability area and limitations Reference

Far field calculation Electromagnetic fields far from source. Very small microwave See Annex A
equipment not used close to body, or large lower-frequency

transmitters at greater distances.

That region of the field of an antenna where the angular field
distribution is essentially independent of the distance from

the antenna. In this region (also called the free space

region), the field has a predominantly plane-wave character,

i.e., locally uniform distribution of electric field strength and
magnetic field strength in planes transverse to the direction

of propagation
Near field calculation Electromagnetic fields very close to the source. There can be See Annex A
an interaction between the radiated fields from the source
and the user
Simulation with/without a phantom Evaluation of measurement results inside the phantom See Annex B
representing a body
Numerical modelling Calculation only See Annex C
Body/limb current Measurement or calculation See Annex C or
D
SAR
Calculation and measurements; 100 kHz – 10 GHz. See Annex E
For modelling See Annex C
E and H measurement
Near or far field. Direct measurement for comparison with See Annex F
reference levels or as input for more detailed assessment
Source modelling Prediction of exposures from calculation of emissions at a See Annex G
specific distance
Direct measurement of physical See Annex D, E
properties: or F
Contact current
The physical characteristics and intended use of the equipment may have an impact on the choice of assessment
method. E.g., radiators of EMF intended for use in close proximity to the body shall be assessed differently from
transmitters intended for fixed installations in buildings.

7.2 Generic procedure for assessment of equipment
The following generic procedure for assessment of equipment involves a decision tree
drawing on information from Tables 1 and 2.
(1) The equipment should be characterised to determine the nature of EMF emissions
(see 8.1) and also the intended usage conditions.

An assessment shall be performed: Fields and body currents should be determined at the
typical user position under normal operating conditions giving the highest emission – see
note – e.g., based on limited pre-tests, but consistent with the normal operating conditions
as specified by the manufacturer.
NOTE For practical reasons it is acceptable to perform the assessment with the equipment being operated
with the maximum settings (e.g., maximum rated load, maximum rated power consumption, maximum speed or
other), consistent with the intended use as specified by the manufacturer. The equipment is operated for a
sufficient period to ensure that the conditions of operation are typical of those during normal use.

62311 © IEC:2007 – 15 –
(2) By measurement or calculation (see 8.1). If these quantities are below the relevant

reference levels, taking into account waveform/frequency content ( 8.1), and any allowed

time and spatial averaging then the equipment is deemed to meet the requirements in this

standard. If not, then go to paragraph (3).

(3) Measured emission values should be compared with any product-specific compliance

criteria (e.g., kind of emission, operating frequency (range), limits) that can be derived for

the equipment (Clause 5). If the emission values are below the product-specific

compliance criteria then the equipment is deemed to meet the requirements in this

standard. If no product-specific compliance criteria (by e.g., the manufacturer) have been

specified for an E-field, H-field or contact current which is to be assessed, or if compliance

criteria have been specified but not met, then go to paragraph (4).

NOTE The technology of some products may allow assumptions about human exposure from the equipment
to be made e.g., always magnetic field, always partial body exposure etc. From these assumptions it may be
possible to derive compliance criteria for that product or product type, e.g., "if the magnetic field strength is
below", or "if the power is below”.
(4) Further assessment involving more detailed measurement, calculation and source/
exposure modelling should be undertaken (see 8.2) to allow comparison of exposure
levels with all relevant basic restrictions on exposure. If the exposures are below the basic
restrictions then the equipment is deemed to meet the requirements in this standard. If
not, then the equipment is deemed not to comply with the requirements in this standard.
This process is summarized in the flowchart in Figure 1.
The decision “low power / inherently compliant” shall be based on an assessment where the
emissions are specified in a performance standard e.g. a transmitter performance standard
and where the output power is limited to a level that can not exceed the basic restriction. It
can also be any other product standard giving the same limitation on the emission level as
e.g. EN 50371. Some products use a technology or input powers that have the consequence
that the emissions cannot exceed the basic restrictions, e.g. non-radiotransmitter products
like wrist-watches, ADSL modems, computers, telecommunications equipment and hi-fi
systems. This shall also be taken into account when the assessment is made.
The choice of assessment method in stages (3) and (4) above is optional, but it must be
suitable for the exposure quantity to be assessed and for the frequency of emission. Where
more than one equally valid assessment method exists for a particular exposure quantity,
then it is acceptable to use only one assessment method for that particular quantity. Where
only one assessment method is chosen, this should be clearly stated and the reasons given
for the choice.
– 16 – 62311 © IEC:2007
Determine source characteristics
(frequency/waveform, power, normal

usage etc.)
Yes
Low power/inherently
compliant?
No
Assess fields/currents at user position
Meets
Yes
ref. level with allowed time and
spatial averaging?
No
Meets other
Yes
product-specific compliance
criterion?
No
Further measurement/calculation/
modeling for comparison with basic
restrictions
Yes
Meets basic restrictions?
No
Compliant Non-compliant
IEC  1534/07
Figure 1 – Assessment flowchart

62311 © IEC:2007 – 17 –
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