SIST EN 50413:2021

SLOVENSKI STANDARD
01-junij-2021
Nadomešča:
SIST EN 50413:2009
SIST EN 50413:2009/A1:2014
Osnovni standard za merjenje in izračunavanje izpostavljenosti ljudi električnim,
magnetnim in elektromagnetnim poljem (0 Hz–300 GHz)
Basic standard on measurement and calculation procedures for human exposure to
electric, magnetic and electromagnetic fields (0 Hz - 300 GHz)
Grundnorm zu Mess- und Berechnungsverfahren der Exposition von Personen in
elektrischen, magnetischen und elektromagnetischen Feldern (0 Hz bis 300 GHz)
Norme de base pour les procédures de mesures et de calculs pour l'exposition des
personnes aux champs électriques, magnétiques et électromagnétiques (0 Hz - 300
GHz)
Ta slovenski standard je istoveten z: EN 50413:2019
ICS:
13.280 Varstvo pred sevanjem Radiation protection
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50413
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2019
ICS 17.200.20; 33.100.01 Supersedes EN 50413:2008 and all of its amendments
and corrigenda (if any)
English Version
Basic standard on measurement and calculation procedures for
human exposure to electric, magnetic and electromagnetic fields
(0 Hz - 300 GHz)
Norme de base pour les procédures de mesures et de Grundnorm zu Mess- und Berechnungsverfahren der
calculs pour l'exposition des personnes aux champs Exposition von Personen in elektrischen, magnetischen und
électriques, magnétiques et électromagnétiques (0 Hz - 300 elektromagnetischen Feldern (0 Hz bis 300 GHz)
GHz)
This European Standard was approved by CENELEC on 2019-09-23. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50413:2019 E
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 General . 12
4.1 General remarks. 12
4.2 Exposure assessment approaches . 12
4.3 Characterization of the field source. 12
4.4 Static and low frequency fields . 13
4.5 High frequency range . 13
4.6 Multiple frequency fields and multiple sources . 13
5 Assessment of human exposure by measurement . 13
5.1 General remarks. 13
5.2 Electromagnetic field measurement . 14
5.2.1 Measurement instrumentation . 14
5.2.2 Measurement protocol . 15
5.3 Body current measurement . 17
5.4 Contact current measurement . 17
5.5 SAR measurement . 17
5.6 Uncertainty of measurement . 18
5.7 Calibration . 19
5.7.1 Low frequency range . 19
5.7.2 High frequency range . 19
6 Assessment of exposure by calculation . 19
6.1 Low frequency . 19
6.2 High frequency . 19
6.3 Uncertainty of calculation . 20
7 Assessment report . 20
7.1 General . 20
7.2 Items to be recorded in the assessment report . 20
7.2.1 Assessment method . 20
7.2.2 Presentation of the measurement results . 20
7.2.3 Presentation of the calculation results . 21
Annex A (informative) Uncertainty assessment for the measurement of EMF . 22
A.1 Steps in establishing an uncertainty budget . 22
A.1.1 Selection of uncertainty contributions . 22
A.1.2 Classes of uncertainty contributions . 22
A.1.3 Probability distribution and standard uncertainty of each contribution . 23
A.1.3.1 General . 23
A.1.3.2 Normal . 23
A.1.3.3 Rectangular . 23
A.1.3.4 U-shaped . 23
A.1.3.5 Triangular . 24
Combined standard uncertainty . 24
A.1.4
A.1.4.1 Sensitivity coefficients . 24
A.1.4.2 Correlated input quantities . 24
A.1.4.3 Combined standard uncertainty . 25
A.1.5 Expanded uncertainty . 25
A.2 Examples for uncertainty budgets . 25
A.2.1 General . 25
A.2.2 Example of an uncertainty budget for field strength measurement using a system with antenna

and spectrum analyser . 25
A.2.3 Example of an uncertainty budget for field strength measurement using a broadband

measurement system . 26
Bibliography . 27

European foreword
This document (EN 50413:2019) has been prepared by CLC/TC 106X “Electromagnetic fields in the human
environment”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2020-09-23
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2022-09-23
conflicting with this document have to be
withdrawn
This document supersedes EN 50413:2008 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CENELEC by the European Commission and the
European Free Trade Association.
1 Scope
This document provides general methods for measurement and calculation of quantities associated with human
exposure to electromagnetic fields in the frequency range from 0 Hz to 300 GHz. It is intended specifically to be used
for the assessment of emissions from products and comparison of these with the exposure limits for the general public
given in Council Recommendation 1999/519/EC, and those given for workers in Directive 2013/35/EU, as appropriate.
It also is intended to be used for assessment of human exposure to electromagnetic fields in the workplace to
determine compliance with the requirements of Directive 2013/35/EU.
This standard deals with quantities that can be measured or calculated external to the body, notably electric and
magnetic field strength or power density, and includes the measurement and calculation of quantities inside the body
that form the basis for protection guidelines. In particular the standard provides information on:
— definitions and terminology,
— characteristics of electromagnetic fields,
— measurement of exposure quantities,
— instrumentation requirements,
— methods of calibration,
— measurement techniques and procedures for evaluating exposure,
— calculation methods for exposure assessment.
Where an applicable electromagnetic field standard specific to a product or technology exists it is expected to be used
rather than this document. EN 62311:—, Table 1 gives a list of relevant standards.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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.
Council Recommendation 1999/519/EC of 12 July 1999, on the limitation of exposure of the general public to
electromagnetic fields (0 Hz to 300 GHz), Official Journal, L199, of 1999-7-30, p.59-70
Directive 2013/35/EU of 26 June 2013, on the minimum health and safety requirements regarding the exposure of
workers to the risks arising from physical agents (electromagnetic fields). Official Journal, L179, of 2013-6-29, p. 1–
EN 61786-1:2014, Measurement of DC magnetic, AC magnetic and AC electric fields from 1 Hz to 100 kHz with regard
to exposure of human beings - Part 1: Requirements for measuring instruments (IEC 61786-1:2013)
EN 62232:2017, Determination of RF field strength, power density and SAR in the vicinity of radiocommunication base
stations for the purpose of evaluating human exposure (IEC 62232:2017)
EN 62311:—, Assessment of electronic and electrical equipment related to human exposure restrictions for
electromagnetic fields (0 Hz - 300 GHz) (IEC 62311:—)
ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
Under preparation. Stage at time of Formal Vote: FprEN 62311:2019.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
action level
operational levels established for the purpose of simplifying the process of demonstrating the compliance with relevant
ELVs or, where appropriate, to take relevant protection or prevention measures specified in this Directive
[SOURCE: Directive 2013/35/EU]
3.2
antenna
device that serves as a transducer between a guided wave for example in a coaxial cable and a free space wave, or
vice versa
3.3
basic restriction
restriction on exposure to electromagnetic fields that is based directly on established health effects and biological
considerations
[SOURCE: Council Recommendation 1999/519/EC, modified]
3.4
contact current
current flowing into the body resulting from contact with a conductive object in an electromagnetic field
Note 1 to entry: The contact current is expressed in ampere (A).
3.5
current density
J
current per unit cross-sectional area flowing inside the human body as a result of direct exposure to electromagnetic
fields
Note 1 to entry: The current density is expressed in ampere per metre squared (A/m ).
3.6
electric flux density
D
vector quantity obtained at a given point by adding the electric polarization P to the product of the electric field strength
E and the permittivity of free space ε0:
D = ε0 E + P
Note 1 to entry: Electric flux density is expressed in coulombs per metre squared (C/m ).
Note 2 to entry: In vacuum, the electric flux density is at all points equal to the product of the electric field strength and the
permittivity of free space: D = ε E.
3.7
electric field strength
E
vector field quantity E which exerts a force F equal to the product of E and the electric charge Q of the particle on any
charged particle at rest:
F = q E
Note 1 to entry: Electric field strength is expressed in volt per metre (V/m).
[SOURCE: IEV 121-11-18]
3.8
electromagnetic fields
EMF
static electric, static magnetic and time-varying electric, magnetic and electromagnetic fields with frequencies up to
300 GHz
[SOURCE: Directive 2013/35/EU]
3.9
exposure
phenomenon occurring whenever and wherever a person is subjected to external electromagnetic fields or to contact
current
[SOURCE: EN 50499:—]
3.10
exposure level
value of the quantity used to assess exposure
3.11
exposure limits
guideline or restriction values on exposure that are given in international or national standards, guidelines or directives
on human exposure to electromagnetic fields
Note 1 to entry: For Directive 2013/35/EU, the exposure limits are the action levels and the exposure limit values and also the
other specific requirements in that Directive to avoid other risks related to workplace exposure to electromagnetic fields.
[SOURCE: EN 50499:—]
3.12
exposure limit value (ELV)
limits on exposure to electromagnetic fields which are based on biophysical and biological considerations, in particular
on the basis of scientifically well-established short-term and acute direct effects, i.e. thermal effects and electrical
stimulation of tissues
Note 1 to entry: Compliance with these limits will ensure that workers exposed to electromagnetic fields are protected against
known adverse health effects (from Directive 2013/35/EU).
3.13
far-field region
region of the electromagnetic field of an antenna wherein the predominant components of the field are those which
represent a propagation of energy and wherein the angular field distribution is essentially independent of the distance
from the antenna
Note 1 to entry: In the far field region, all the components of the electromagnetic field decrease in inverse proportion to the
distance from the antenna.
Note 2 to entry: For a broadside antenna having a maximum overall dimension D which is large compared to the wavelength λ,
the far field region is commonly taken to exist at distances greater than 2D /λ, from the antenna in the direction of maximum
radiation.
[SOURCE: IEV 712-02-02]
3.14
high frequency fields
electromagnetic fields of frequency 10 MHz ≤ f ≤ 300 GHz
3.15
impedance of free space
Z
square root of the free space permeability µ divided by the permittivity of free space ε for a plane wave,
0 0
µ
Z=≈≈120πΩ 377Ω
ε
3.16
intermediate frequency fields
electromagnetic fields of frequency 100 kHz ≤ f ≤ 10 MHz
3.17
isotropic
qualifies a physical medium or technical device where the relevant properties are independent of the direction
3.18
induced current
I
current induced inside the body as a result of direct exposure to electromagnetic fields
Note 1 to entry: Induced current is expressed in ampere (A).
3.19
low frequency field
electromagnetic field of frequency 1Hz ≤ f < 100 kHz
3.20
magnetic flux density
B
vector field quantity which exerts on any charged particle having velocity v a force F equal to the product of the vector
product v x B and the electric charge q of the particle:
F = q (v × B)
Note 1 to entry: The magnitude of the magnetic flux density is expressed in Tesla (T).
[SOURCE: IEV 121-11-19, modified]
3.21
magnetic field strength
H
vector quantity obtained at a given point by subtracting the magnetization M from the magnetic flux density B divided
by the permeability of free space μ :
B
HM−
µ
Note 1 to entry: Magnetic field strength is expressed in ampere per metre (A/m).
Note 2 to entry: In a vacuum, the magnetic field strength is at all points equal to the magnetic flux density divided by the
permeability of free space: H = B / μ0.
3.22
modulation
process of modifying the amplitude, phase and/or frequency of a periodic waveform in order to convey information
3.23
near-field region
region generally in proximity to an antenna or other radiating structure, in which the electric and magnetic fields do not
have a substantially plane-wave character, but vary considerably from point to point
Note 1 to entry: The near-field region is further subdivided into the reactive near-field region, which is closest to the radiating
structure and that contains most or nearly all of the stored energy, and the radiating near-field region where the radiation field
predominates over the reactive field, but lacks substantial plane-wave character and is complex in structure.
3.24
permeability
µ
property of a material which defines the relationship between magnetic flux density B and magnetic field strength H
Note 1 to entry: It is commonly used as the combination of the permeability of free space (µ ) and the relative permeability for
specific materials (µ ):
r
B
µ µµ
r0
H
where
µ is the relative permeability of the material
r
µ is the permeability of vacuum
Note 2 to entry: The permeability is expressed in henry per metre (H/m)
==
=
3.25
permittivity
ε
property of a dielectric material, e.g., biological tissue, defined by the electric flux density D divided by the electric field
strength E:
ε = ε ε = D / E
r 0
where
ε is the relative permittivity of the material
r
ε is the permittivity of vacuum
Note 1 to entry: The permittivity is expressed in farads per metre (F/m).
3.26
phantom
simplified model of the human body or body part composed of materials with dielectric properties close to the organic
tissue
3.27
power density
S
power per unit area normal to the direction of electromagnetic wave propagation
Note 1 to entry: The power density is expressed in Watts per square m (W/m ).
Note 2 to entry: For plane waves the power density (S), electric field strength (E) and magnetic field strength (H) are related by
the impedance of free space Z :
E
S Z H EH
Z
Note 3 to entry: Although many survey instruments indicate power density units, the actual quantities measured are E or H, or
the square of those quantities.
3.28
probe
input device of a measuring instrument, generally made as a separate unit, which transforms the measured input value
to a suitable output value
= ==
3.29
reference level
provided for practical exposure assessment purposes to determine whether the basic restrictions are likely to be
exceeded
Note 1 to entry: Some reference levels are derived from relevant basic restrictions using measurement and/or computational
techniques, and some address perception and adverse indirect effects of exposure to EMF.
Note 2 to entry: In any particular exposure situation, measured or calculated values can be compared with the appropriate
reference level. Compliance with the reference level will ensure compliance with the relevant basic restriction. If the measured or
calculated value exceeds the reference level, it does not necessarily follow that the basic restriction will be exceeded. However,
whenever a reference level is exceeded it is necessary to test compliance with the relevant basic restriction and to determine
whether additional protective measures are necessary.
[SOURCE: Council Recommendation 1999/519/EC]
3.30
root-mean-square value
RMS
effective value or the value associated with joule heating, of a periodic
electromagnetic wave, obtained by taking the square root of the mean of the squared value of a function
Note 1 to entry: Although many survey instruments in the high frequency range indicate RMS, the actual quantity measured is
root-sum-square (RSS) (equivalent field strength).
[SOURCE: EN 62311:—]
3.31
specific absorption rate
SAR
time derivative of the incremental electromagnetic energy (dW) absorbed by (dissipated in) an incremental mass (dm)
contained in a volume element (dV) of given mass density (ρ):
  
d dW d dW
SAR
  
dt dm dt ρ dV
  
Note 1 to entry: SAR is expressed in watts per kilogram (W/kg)
Note 2 to entry: SAR can be calculated by:
σ E
i
SAR=
ρ
where
E RMS value of the electric field strength in the tissue in V/m;
i
σ conductivity of body tissue in S/m;
ρ
density of body tissue in kg/m ;
3.32
static and quasi-static field
electromagnetic field of frequency f < 1 Hz
==
3.33
unperturbed field
field that exists in a space in the absence of a person or an object that could influence the field
Note 1 to entry: The field values measured or calculated with a person or object present could differ considerably.
4 General
4.1 General remarks
Electromagnetic fields can have direct and indirect effects on the human body. Depending on the frequency of the
fields, these can be effects on the nervous system in the low frequency range and thermal effects in the high frequency
range. Besides these direct effects there exist several indirect effects such as the occurrence of contact currents or
the possible influence on the intended operation of active medical implants.
The Council Recommendation 1999/519/EC provides basic restrictions and derived reference levels for exposure of
the general public.
The Directive 2013/35/EU provides exposure limit values and derived action level for exposures in the workplace.
The basic restrictions given in the Recommendation, and the exposure limit values given in the Directive are in both
cases expressed in terms of quantities that are mostly not directly measurable: for example induced currents density
or internal electric field strength for low frequency electromagnetic fields, specific absorption rate (SAR) for higher
frequency fields.
The reference levels given in the Recommendation, and the action levels given in the Directive, are derived from these
and are expressed in terms of quantities that are measurable: including electric field strength, magnetic field strength,
contact current and limb induced current.
Exposure assessments may be based either on the reference levels (action levels), or on the basic restriction
(exposure limit value) taking account of specific characteristics of the particular field source or device being assessed.
The range for low frequency measurements is from 1 Hz up to 100 kHz. The range for intermediate frequency
measurement is from 100 kHz to 10 MHz and the range for high frequency measurements is from 10 MHz up to
300 GHz.
NOTE The underlying physiological effects of electromagnetic fields on the human body have no sharp frequency limit value
to distinguish between stimulation and thermal effects; this also shows up in the selection of the measurement equipment
necessary.
4.2 Exposure assessment approaches
In general, either calculation or measurement procedures can be used for the assessment of exposure. In specific
circumstances there may be advantages of using one or the other of these.
4.3 Characterization of the field source
To make meaningful measurements or calculations, the behaviour and characteristics (for example frequency, time-
variability of emission, input power) of the source of exposure (field or current) shall be determined and the operation
of the measurement equipment understood. Irrespective of the type of signal, time domain measurement may be used.
This can be especially helpful for non-sinusoidal, very fast, and pulsed signals. Also, the exposure quantities assessed
should include all those needed to assess the extent of human exposure arising from the operation of the source.
What shall be assessed is the maximum level to which someone is exposed under the operating conditions of the
source.
The expected emission characteristics of the source should be understood, and it should be confirmed that these
match the results of measurements or calculations. Sometimes the source will be well documented, in which case the
predicted emissions may be comparatively simple to establish. Sometimes the source will be undocumented and its
characteristics shall be determined mostly by measurement. There can also be influences on the behaviour of the
source, such as ground conductivity, presence of reflecting objects etc. and these shall be considered.
More information is given in EN 62311:—, Table 2.
4.4 Static and low frequency fields
The static and low frequency electric and magnetic fields are effectively independent from each other and shall – if
necessary – both be assessed. For a given exposure scenario the electric field strength depends on the voltage used;
the magnetic field strength or magnetic flux density depends on the electric current.
4.5 High frequency range
There exist several field types which are assessed differently depending on the distance r from and the dimension d
of the radiating source. Table 1 indicates whether to measure E or H or both at different distances from the field source.
If it is not known whether the conditions for far-field or radiating near-field region apply, then it is necessary to evaluate
both E and H.
Table 1 — Evaluation parameters
Reactive near-field Radiating near-field Far-field region
region region
Distance r r < λ 2 2
λ < r < 2d / λ λ < 2d / λ < r
E,H approximately 1/r No No Yes
Z = E/H ≠ Z approximately Z = Z
0 0 0
To measure E and H E or H E or H
Here d is the biggest dimension of the radiating structure; e.g. diameter of a parabolic antenna., d may also
include the metallic supporting structure of the antenna
4.6 Multiple frequency fields and multiple sources
All relevant frequency components and field sources shall be taken into account when assessing exposure. In general,
low frequency and high frequency fields shall be evaluated separately because their effects are different but at
intermediate frequency range (100 kHz to 10 MHz) where both types of effect are possible, it is necessary to consider
both effects. Proper summation procedures are given for the low frequency range in IEC 61786-2:2014, 4.2. Proper
summation procedures are given for the high frequency and intermediate frequency ranges in EN 62311:—.
5 Assessment of human exposure by measurement
5.1 General remarks
Measurements of human exposure to electromagnetic fields can be classified as follows:
— measurement of electromagnetic field quantities (i.e. B, E, H, S);
— measurement of the limb induced current;
— measurement of the contact current;
— measurement of the Specific Absorption Rate (SAR);
— measurement of the temperature.
EMF measurements shall differentiate between low and high-frequency field measurements.
5.2 Electromagnetic field measurement
5.2.1 Measurement instrumentation
5.2.1.1 Low frequency range
Electric and magnetic field meters shall be compliant with the requirements of EN 61786-1:2014.
Magnetic flux density measurements shall be made with three-axis instruments and shall be of the resultant magnetic
field,
NOTE 1 Using single-axis instruments is possible in some cases, e.g. to know the direction of the field and the maximum
magnetic field, or in order to investigate the orientation and shape of the magnetic field ellipse, and in cases when the direction of
a linearly polarized field is already known.
NOTE 2 Some three-axis instrumentation can also determine the field parameters mentioned above.
The size of the probe or sensing elements shall be appropriate to the spatial variation of the field that is measured.
The sensing elements should be of area 0,01 m or smaller (EN 61786-1:2014, 5.8.2).
The pass-band of the instrument shall be appropriate to the frequency content of the field being measured. Where the
field is such that the pass-band of the instrument could significantly affect the reading (i.e. where more than one
frequency is present in the field), the pass-band shall be recorded and included in the report.
When the magnetic field is produced by a power system, the frequencies present will usually be the fundamental
(50 Hz or 60 Hz), plus the first few harmonics. The minimum pass-band used for measuring such fields shall extend
from the fundamental frequency to 800 Hz. A narrower pass-band may be used only if it can be demonstrated that the
harmonic content is sufficiently small for the measurement result to be negligibly different, e.g. near power lines, or if
there is a specific reason for measuring a narrower range of frequencies.
When measuring the fields produced by sources other than the power system, the pass-band shall be chosen
appropriately. Fields produced by some transportation systems have a lower fundamental frequency, while e.g.
induction heaters, video display terminals, commercial airplanes, ships, and the harmonics produced by variable speed
motors can produce fields with higher frequencies.
When extending the pass-band to lower frequencies, care shall be taken to avoid errors caused by the motion of coil
probes in static fields. Such errors can generally be avoided by holding the coil stationary or by selecting an appropriate
frequency range.
5.2.1.2 High frequency range
The bandwidth and the measurement range of the instrument shall be appropriate to the frequency of the EM field
being measured.
Broadband measuring equipment does not give spectral information on the measured field. Therefore, the result,
which is usually the total field strength of all spectral components within the measurement bandwidth, shall be
compared with the lowest action level or reference level. If the frequencies of the source (or sources) are known, it is
appropriate to use the lowest exposure action level or reference level at those frequencies. A shaped frequency
response probe can also be used to conclude on compliance with exposure limits.
Perturbation from the environment (e.g. temperature, humidity, mechanical vibration, levels of EMC-Phenomena)
should be avoided.
To take in account the polarization and the incidence of signals, the field should be evaluated isotropically. If probes
with a single sensor element responding only to one field component are used, they should be oriented to read the
maximum value, or should be aligned in three mutually orthogonal directions to measure separately the spatial
components of the field.
The measurement equipment shall meet the requirements given in EN 62232:2017.
5.2.2 Measurement protocol
5.2.2.1 General
Sometimes the exposure position is well defined, but often it may be necessary to determine the location at which
maximum exposure will occur. This may be achieved by either a preliminary survey of the areas around a source or
by the setting up a spatial 2D/3D-measurement matrix. Measurements should be made at all positions on the matrix.
When the position of maximum exposure has been identified then detailed measurements should be made. The
distances between different measurement points will depend e.g. on the kind of chosen measurement method and on
frequency.
5.2.2.2 Low frequency range
5.2.2.2.1 General
The electric field to be measured shall be the unperturbed field (without presence of a person). The magnetic field
may be measured in presence of a person, because the magnetic field is not perturbed by the presence of a person.
5.2.2.2.2 AC magnetic field
Measurements in an approximately uniform magnetic field correspond to exposure of the whole human body if present
at the measurement location at the time of the measurements. This is the case under power lines (see EN 62110).
In some cases the concept of spatial averaging may be applicable. Whether or not averaging is applicable highly
depends on the spatial field characteristic caused by the source and the distance of the exposed person to the source.
If averaging is applied in a case where one or more of the measured values is above the reference levels or action
levels, it is necessary to provide sound evidence that the assessment based on the averaged values does not lead to
a violation of the underlying basic restrictions or exposure limit values, respectively. It is more likely to be possible to
use the concept of average exposure levels when the distance between the source and the body is greater than 20 cm,
depending on the characteristics of the field source.
In order to determine the average exposure levels, the field shall be measured at different heights and positions, taking
into account the position of the human body, and the results averaged. EN 62110 gives a protocol for measuring public
exposure to magnetic field emitted by electric installations, which defines 3 heights of measurements.
The measurement protocol shall specify the measurement distances between the measurement point and the sources
(or the walls or fences or surfaces). Some standards define distances of measurement in specific situations (see
IEC 61786-2:2014).
As part of the process for developing a measurement protocol for determining human exposure to magnetic fields, the
measurement goals and methods for achieving them shall be clearly indicated. A clear definition of the goals is needed
to determine instrumentation and calibration requirements, e.g. instrumentation pass-band, magnitude range, and
frequency calibration points. The measurement protocol should indicate which field parameter(s) shall be measured,
where the measurements shall be performed, and how the measurements shall be performed. It is important to note
that, in general, a single measurement protocol will not be suitable for all measurement situations.
The magnetic field is proportional to the current and so may vary during the measurements. So, this variation shall be
known in order to interpret the results. This could be done by recording the current in the load or by recording the
magnetic field at a fixed place during the measurements.
5.2.2.2.3 DC magnetic field
The main difference between measuring AC and DC magnetic fields is the influence of the geomagnetic field.
In the case of DC electric networks, the protocol should be derived from EN 62110. If the DC line is undergrounded,
the DC field at the location of the body should be considered as uniform (in the sense of EN 62110), so that a
measurement at 1 m height should be sufficient.
The geomagnetic field shall be measured at the beginning and at the end of the measurements, on each side on the
cable. As the geomagnetic field and the DC field emitted by the cables are vectors, it is not possible to simply subtract
the geomagnetic field component. The measured magnetic field shall be reported, as it is. The geomagnetic field
component shall also be reported.
5.2.2.2.4 AC electric field
Unperturbed field measurements shall be made with three-axis instruments and shall be of the resultant electric field.
NOTE Using single-axis instruments is possible in some case, e.g. when the direction of the field is already known.
The pass-band of the instrument shall be appropriate to the frequency content of the field being measured. Where the
field is such that the pass-band of the instrument could significantly affect the reading (i.e. where more than one
frequency is present in the field), the pass-band shall be recorded and included in the report.
When electric fields are produced by electric power systems, i.e. power lines, transformers, and so forth, the
predominant frequency is the power frequency 50 Hz or 60 Hz. An instrument with a narrow pass-band centred about
the power frequency will be suitable in such cases for measuring the RMS value of the electric field.
When measuring electric fields from other sources, e.g. on commercial aeroplanes, ships, and some electric trains,
the fundamental frequency can differ significantly from 50 Hz/60 Hz, and the pass-band shall be chosen appropriately.
During electric field measurements, particular attention should be given to avoiding proximity effects of the observer
as well as other people who may be in the vicinity of the field probe. Significant perturbation of the field can occur,
capable of introducing unacceptable errors in the measurement. So a minimum distance of 2 m shall be respected
between operator and probe.
Electric fields are very easily perturbed by the presence of conductive objects, even if these objects are poor electrical
conductors (trees, fences, vegetation, buildings, etc.). All movable objects should be removed whenever possible. If
not, then the distance between the probe and the object should be equal to at least three times the height of the object
(non-permanent object) or to 1 m (permanent object), if possible. Objects that cannot be removed shall be listed,
indicating their dimensions and location.
The probe shall be put on an insulated tripod (see EN 61786-1:2014, 5.8.4).
Electric field measurements may be in error if the relative humidity is more than 70 % (see EN 61786-1:2014, 5.5).
It should be recognized that measurements in an approximately uniform electric field correspond to exposure of the
whole human body if present at the measurement location at the time of measurements. Electric field measurements
in non-uniform fields have a more restrictive interpretation when determining human exposure, i.e. the field
measurement represents human exposure only for that portion of the human anatomy which would coincide with the
measurement location.
As part of the process for developing a measurement protocol to determine human exposure to electric fields, the
measurement goals and methods for achieving them shall be clearly indicated. A clear definition of the goals is needed
to determine instrumentation and calibration requirements, e.g. instrumentation pass-band, magnitude range, and
frequency calibration points. The measurement protocol shall indicate which field parameter(s) should be measured,
where the measurements shall be performed, and how the measurements shall be performed. It is important to note
that, in general, a single measurement protocol will
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