SIST IEC 60479-1:2020
Effects of current on human beings and livestock - Part 1: General aspects
Effects of current on human beings and livestock - Part 1: General aspects
IEC 60479-1 provides basic guidance on the effects of shock current on human beings and livestock. For a given current path through the human body, the danger to persons depends mainly on the magnitude and duration of the current flow. However, the time/current zones specified in the following clauses are, in many cases, not directly applicable in practice for designing measures of protection against electrical shock. The necessary criterion is the admissible limit of touch voltage (i.e. the product of the current through the body called touch current and the body impedance) as a function of time. The relationship between current and voltage is not linear because the impedance of the human body varies with the touch voltage, and data on this relationship is therefore required. The different parts of the human body (such as the skin, blood, muscles, other tissues and joints) present to the electric current a certain impedance composed of resistive and capacitive components. The values of body impedance depend on a number of factors and, in particular, on current path, on touch voltage, duration of current flow, frequency, degree of moisture of the skin, surface area of contact, pressure exerted and temperature. The impedance values indicated in this document result from a close examination of the experimental results available from measurements carried out principally on corpses and on some living persons. Knowledge of the effects of alternating current is primarily based on the findings related to the effects of current at frequencies of 50 Hz or 60 Hz which are the most common in electrical installations. The values given are, however, deemed applicable over the frequency range from 15 Hz to 100 Hz, threshold values at the limits of this range being higher than those at 50 Hz or 60 Hz. Principally the risk of ventricular fibrillation is considered to be the main mechanism of death of fatal electrical accidents. Accidents with direct current are much less frequent than would be expected from the number of DC applications, and fatal electrical accidents occur only under very unfavourable conditions, for example, in mines. This is partly due to the fact that with direct current, the letgo of parts gripped is less difficult and that for shock durations longer than the period of the cardiac cycle, the threshold of ventricular fibrillation is considerably higher than for alternating current. This basic safety publication is primarily intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and lSO/lEC Guide 51. It is not intended for use by manufacturers or certification bodies. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the relevant publications.
Vplivi električnega toka na ljudi in živali – 1. del: Splošno
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2020
Vplivi električnega toka na ljudi in živali – 1. del: Splošno
Effects of current on human beings and livestock - Part 1: General aspects
Ta slovenski standard je istoveten z:
ICS:
13.200 Preprečevanje nesreč in Accident and disaster control
katastrof
29.020 Elektrotehnika na splošno Electrical engineering in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
IEC 60479-1 ®
Edition 1.0 2018-12
INTERNATIONAL
STANDARD
BASIC SAFETY PUBLICATION
Effects of current on human beings and livestock –
Part 1: General aspects
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.200; 29.020 ISBN 978-2-8322-6295-5
– 2 – IEC 60479-1:2018 IEC 2018
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 10
3 Terms and definitions . 10
3.1 General definitions . 10
3.2 Effects of sinusoidal alternating current in the range 15 Hz to 100 Hz . 11
3.3 Effects of direct current . 12
4 Electrical impedance of the human body and livestock . 13
4.1 General . 13
4.2 Internal impedance of the human body (Z ) . 13
i
4.3 Impedance of the skin (Z ) . 13
s
4.4 Total impedance of the human body (Z ) . 13
T
4.5 Factors affecting initial resistance of the human body (R ) . 14
4.6 Values of the total impedance of the human body (Z ) . 14
T
4.6.1 Total body impedance dependence for large, medium and small surface
areas of contact . 14
4.6.2 Sinusoidal alternating current 50/60 Hz for large surface areas of contact . 14
4.6.3 Sinusoidal alternating current 50/60 Hz for medium and small surface
areas of contact . 17
4.6.4 Sinusoidal alternating current with frequencies up to 20 kHz and above . 20
4.6.5 Direct current . 21
4.7 Value of the initial resistance of the human body (R ) . 22
4.8 Characteristics of the impedance of the body of livestock . 22
5 Effects of sinusoidal alternating current in the range of 15 Hz to 150 Hz . 22
5.1 General . 22
5.2 Threshold of perception . 22
5.3 Threshold of reaction . 22
5.4 Immobilization . 22
5.5 Threshold of let-go . 23
5.6 Threshold of ventricular fibrillation . 23
5.7 Other effects related to electric shocks . 23
5.8 Effects of current on the skin . 24
5.9 Description of time/current zones (see Figure 20) . 24
5.10 Application of heart-current factor (F). 25
6 Effects of direct current . 26
6.1 General . 26
6.2 Threshold of perception and threshold of reaction . 26
6.3 Threshold of immobilization and threshold of let-go . 26
6.4 Threshold of ventricular fibrillation . 26
6.5 Other effects of current . 27
6.6 Description of time/current zones (see Figure 22) . 27
6.7 Heart factor . 28
6.8 Effects of anodic versus cathodic DC currents . 45
Annex A (normative) Measurements of the total body impedances Z made on living
T
human beings and on corpses and statistical analysis of the results . 48
Annex B (normative) Influence of frequency on the total body impedance (Z ) . 51
T
IEC 60479-1:2018 IEC 2018 – 3 –
Annex C (normative) Total body resistance (R ) for direct current . 52
T
Annex D (informative) Examples of calculations of ZT . 53
Annex E (informative) Theories of ventricular fibrillation . 56
Annex F (informative) Quantities of upper limit of vulnerability (ULV)and lower limit of
vulnerability (LLV) . 57
Annex G (informative) Circuit simulation methods in electric shock evaluation . 58
Annex H (normative) Effects of currents passing through the body of livestock . 61
H.1 General . 61
H.2 Principal consideration of the risk of ventricular fibrillation for livestock . 61
H.3 Characteristics of the impedance of the body of livestock . 62
H.4 Internal impedance of animals (Z ) . 62
i
H.5 Impedance of the hide and skin (Z ) . 63
P
H.6 Impedance (resistance) of the hoof (Z , R ) . 63
h h
H.7 Total body impedance (Z ) . 63
T
H.8 Initial body resistance (R ) . 64
H.9 Values of the total body impedance (Z ) . 64
T
H.10 Values of the initial resistance of the body (R ) . 65
H.11 Effects on livestock of sinusoidal alternating current in the range from 15 Hz
to 100 Hz . 65
H.11.1 General . 65
H.11.2 Threshold of reaction . 66
H.11.3 Threshold of ventricular fibrillation . 66
Bibliography . 69
Figure 1 – Impedances of the human body . 28
Figure 2 – Internal partial impedances Z of the human body . 29
ip
Figure 3 – Simplified schematic diagram for the internal impedances of the human
body . 30
Figure 4 – Total body impedance Z (50 %) for a current path hand to hand, for large
T
surface areas of contact in dry, water-wet and saltwater-wet conditions for a percentile
rank of 50 % of the population for touch voltages U = 25 V to 700 V, AC 50/60 Hz . 31
T
Figure 5 – Dependence of the total impedance Z of one living person on the surface
T
area of contact in dry conditions and at touch voltage (50 Hz) . 32
Figure 6 – Dependence of the total body impedance Z on the touch voltage U for a current
T T
path from the tips of the right to the left forefinger compared with large surfaceareas of
contact from the right to the left hand in dry conditions measured on one living person, touch
voltage range U = 25 V to 200 V, AC 50 Hz, duration of current flow max. 25 ms . 33
T
th
Figure 7 – Dependence of the total body impedance Z for the 50 percentile rank of
T
a population of living human beings for large, medium and small surface areas of
2 2 2
contact (order of magnitude 10 000 mm , 1 000 mm and 100 mm respectively) in
dry conditions at touch voltages U = 25 V to 200 V AC 50/60 Hz . 34
T
th
Figure 8 – Dependence of the total body impedance Z for the 50 percentile rank of
T
a population of living human beings for large, medium and small surface areas of
2 2 2
contact (order of magnitude 10 000 mm , 1 000 mm and 100 mm respectively) in
water-wet conditions at touch voltages U = 25 V to 200 V, AC 50/60 Hz . 35
T
th
Figure 9 – Dependence of the total body impedance Z for the 50 percentile rank of
T
a population of living human beings for large, medium and small surface areas of
2 2 2
contact (order of magnitude 10 000 mm , 1 000 mm and 100 mm respectively) in
saltwater-wet conditions at touch voltages U = 25 V to 200 V, AC 50/60 Hz . 36
T
– 4 – IEC 60479-1:2018 IEC 2018
Figure 10 – Values for the total body impedance Z measured on 10 living human
T
beings with a current path hand to hand and large surface areas of contact in dry
conditions at a touch voltage of 10 V and frequencies from 25 Hz to 20 kHz . 37
Figure 11 – Values for the total body impedance Z measured on one living human
T
being with a current path hand to hand and large surface areas of contact in dry
conditions at a touch voltage of 25 V and frequencies from 25 Hz to 2 kHz . 37
Figure 12 – Frequency dependence of the total body impedance Z of a population for
T
a percentile rank of 50 % for touch voltages from 10 V to 1 000 V and a frequency
range from 50 Hz to 150 kHz for a current path hand to hand or hand to foot, large
surface areas of contact in dry conditions . 38
Figure 13 – Statistical value of total body impedances Z and body resistances R for
T T
a percentile rank of 50 % of a population of living human beings for the current path
hand to hand, large surface areas of contact, dry conditions, for touch voltages up to
700 V, for AC 50/60 Hz and DC . 38
Figure 14 – Dependence of the alteration of human skin condition on current density
i and duration of current flow . 39
T
Figure 15 – Electrodes used for the measurement of the dependence of the
impedance of the human body Z on the surface area of contact . 40
T
Figure 16 – Oscillograms of touch voltages U and touch currents I for AC, current
T T
path hand to hand, large surface areas of contact in dry conditions taken from
measurements . 41
Figure 17 – Occurrence of the vulnerable period of ventricles during the cardiac cycle . 42
Figure 18 – Triggering of ventricular fibrillation in the vulnerable period – Effects on
electro-cardiogram (ECG) and blood pressure . 42
Figure 19 – Fibrillation data for dogs, pigs and sheep from experiments and for
persons calculated from statistics of electrical accidents with transversal direction of
current flow hand to hand and touch voltages U = 220 V and 380 V AC with body
T
impedances Z (5 %) . 43
T
Figure 20 – Conventional time/current zones of effects of AC currents (15 Hz to
100 Hz) on persons for a current path corresponding to left hand to feet (see Table 11) . 44
Figure 21 – Oscillogram of touch voltages U and touch current I for DC, current path
T T
hand to hand, large surface areas of contact in dry conditions . 44
Figure 22 – Conventional time/current zones of effects of DC currents on persons for
a longitudinal upward current path (see Table 13) . 45
Figure 23 – Let-go currents for 60 Hz sinusoidal current . 45
Figure 24 – Effects of anodic versus cathodic DC currents . 46
Figure 25 – Pulsed DC stimulation of single heart cells . 47
Figure G.1 – Electric shock in electrical model by Hart [33] including startle reaction
effect . 59
Figure H.1 – Current flow and impedances of the relevant parts of the body of a cow
for current path from the nose to the legs. 62
Figure H.2 – Diagrams for an animal, for a current path from the nose to the four legs
(path A) and from the forelegs to the hindlegs (path B) . 62
Figure H.3 – Diagram for the total body impedance for cattle for a percentage of 5 %
of the population . 65
Figure H.4 – Ventricular fibrillation for sheep . 66
Figure H.5 – Minimum fibrillating currents of sheep as a function of weight for a shock
duration of 3 s [55] . 67
Figure H.6 – Minimum fibrillating currents (averages) of various species of livestock as
a function of weight for a shock duration of 3 s [53] . 68
Table 1 – Total body impedances Z for a current path hand to hand AC 50/60 Hz, for
T
large surface areas of contact in dry conditions . 15
IEC 60479-1:2018 IEC 2018 – 5 –
Table 2 – Total body impedances Z for a current path hand to hand AC 50/60 Hz, for
T
large surface areas of contact in water-wet conditions . 16
Table 3 – Total body impedances Z for a current path hand to hand AC 50/60 Hz, for
T
large surface areas of contact in saltwater-wet conditions . 17
Table 4 –Total body impedances Z for a current path hand to hand for medium
T
surface areas of contact in dry conditions at touch voltages U = 25 V to 200 V AC
T
50/60 Hz (values rounded to 25 Ω) . 18
Table 5 – Total body impedances Z for a current path hand to hand for medium
T
surface areas of contact in water-wet conditions at touch voltages U = 25 V to 200 V
T
AC 50/60 Hz (values rounded to 25 Ω) . 19
Table 6 – Total body impedances Z for a current path hand to hand for medium
T
surface areas of contact in saltwater-wet conditions at touch voltages U = 25 V to
T
200 V AC 50/60 Hz (values rounded to 5 Ω) . 19
Table 7 – Total body impedances Z for a current path hand to hand for small surface
T
areas of contact in dry conditions at touch voltages U = 25 V to 200 V AC 50/60 Hz
T
(values rounded to 25 Ω) . 19
Table 8 – Total body impedances Z for a current path hand to hand for small surface
T
areas of contact in water-wet conditions at touch voltages U = 25 V to 200 V AC
T
50/60 Hz (values rounded to 25 Ω) . 20
Table 9 – Total body impedances Z for a current path hand to hand for small surface
T
areas of contact in saltwater-wet conditions at touch voltages U = 25 V to 200 V AC
T
50/60 Hz (values rounded to 5 Ω) . 20
Table 10 – Total body resistances R for a current path hand to hand, direct current,
T
for large surface areas of contact in dry conditions . 21
Table 11 – Time/current zones for AC 15 Hz to 100 Hz for hand to feet pathway –
Summary of zones of Figure 20 . 25
Table 12 – Heart-current factor F for different current paths . 26
Table 13 – Time/current zones for direct current for hand to feet pathway – Summary
of zones of Figure 22 . 28
Table A.1 – Total body impedances Z , electrodes type A for dry conditions and
T
deviation factors F (5 % and 95 %) . 48
D
Table A.2 – Total body impedances Z , electrodes type B for dry, water-wet and
T
saltwater-wet conditions and deviation factors F (5 % and 95 %) . 48
D
Table A.3 – Total body impedances Z for dry, water-wet and saltwater-wet conditions
T
and deviation factors F (5 % and 95 %) . 48
D
Table A.4 – Deviation factors F (5 %) and F (95 %) for dry and water-wet conditions
D D
in the touch voltage range U = 25 V up to 400 V for large, medium and small surface
T
areas of contact . 50
th
Table D.1 – 50 percentile values for the total body impedance for a current path
hands-feet, medium surface area of contact for hands, large for feet, reduction factor
0,8, dry conditions, touch currents I and electrophysiological effects . 54
T
Table G.1 – Body impedance examples (uncompensated) . 59
Table H.1 – Impedance (resistance) of the hooves of cattle (Z , R ) for AC voltages up
h h
to 230 V, 50/60 Hz . 63
Table H.2 – Total body impedances Z for AC 50/60 Hz for cattle for touch voltages up
T
to 230 V . 64
Table H.3 – Initial body resistance R for cattle . 65
Table H.4 – Threshold of ventricular fibrillation for AC 50/60 Hz [53] [54] for different
species of livestock, for a shock duration of 3 s . 67
– 6 – IEC 60479-1:2018 IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EFFECTS OF CURRENT ON HUMAN BEINGS
AND LIVESTOCK –
Part 1: General aspects
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
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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governmental organizations liaising with the IEC also participate in this preparation. 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 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 IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 60479-1 has been prepared by IEC technical committee 64:
Electrical installations and protection against electric shock.
This first edition cancels and replaces IEC TS 60479-1:2005, Amendment 1:2016 and
IEC TR 60479-3:1998. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to
IEC TS 60479-1 and IEC TR 60479-3:
• The contents of IEC TR 60479-3 relating to aspects unique to the effects of current
passing through the bodies of livestock have been incorporated into a new Annex H
(normative).
It has the status of a basic safety publication in accordance with IEC Guide 104.
IEC 60479-1:2018 IEC 2018 – 7 –
The text of this International Standard is based on the following documents:
CDV Report on voting
64/2275/CDV 64/2343/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60479 series, published under the general title Effects of current
on human beings and livestock, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
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.
– 8 – IEC 60479-1:2018 IEC 2018
INTRODUCTION
In order to avoid errors in the interpretation of this document, it should be emphasized that
the data given herein is mainly based on experiments with animals as well as on information
available from clinical observations. Only a few experiments with shock currents of short
duration have been carried out on living human beings.
On the evidence available, mostly from animal research, the values are so conservative that
this document applies to persons of normal physiological conditions including children,
irrespective of age and weight.
There are, however, other aspects which should be taken into account, such as probability of
faults, probability of contact with live or faulty parts, ratio between touch voltage and fault
voltage, experience gained, technical feasibilities, and economics. These parameters should
be considered carefully when establishing safety requirements, for example, operating
characteristics of protective devices for electrical installations.
The form of the document, as has been adopted, summarizes results so far achieved which
are being used by technical committee 64 as a basis for establishing requirements for
protection against shock. These results are considered important enough to justify an IEC
publication which may serve as a guide to other IEC committees and countries having need of
such information.
This document applies to the threshold of ventricular fibrillation which is the main cause of
deaths by electric current. The analysis of results of recent research work on cardiac
physiology and on the fibrillation threshold, taken together, has made it possible to better
appreciate the influence of the main physical parameters and, especially, of the duration of
the current flow.
This document contains information about body impedance and body current thresholds for
various physiological effects. This information can be combined to derive estimates of AC and
DC touch voltage thresholds for certain body current pathways, contact moisture conditions,
and skin contact areas.
This document refers specifically to the effects of electric current. When an assessment of the
harmful effects of any event on human beings and livestock is being made, other non-electric
phenomena, including falls, heat, fire, or others should be taken into account. These matters
are beyond the scope of this document, but may be extremely serious in their own right.
Further experimental data are under consideration, such as recent ongoing experimental work
on "current induced heart fibrillation by excitation with discrete Fourier spectra" which is
intended to contribute to frequency factor data.
The characteristics of the impedance of the body of livestock and the effects of sinusoidal
alternating currents are described in Annex H.
IEC 60479-1:2018 IEC 2018 – 9 –
EFFECTS OF CURRENT ON HUMAN BEINGS
AND LIVESTOCK –
Part 1: General aspects
1 Scope
This part of IEC 60479 provides basic guidance on the effects of shock current on human
beings and livestock.
For a given current path through the human body, the danger to persons depends mainly on
the magnitude and duration of the current flow. However, the time/current zones specified in
the following clauses are, in many cases, not directly applicable in practice for designing
measures of protection against electrical shock. The necessary criterion is the admissible limit
of touch voltage (i.e. the product of the current through the body called touch current and the
body impedance) as a function of time. The relationship between current and voltage is not
linear because the impedance of the human body varies with the touch voltage, and data on
this relationship is therefore required. The different parts of the human body (such as the skin,
blood, muscles, other tissues and joints) present to the electric current a certain impedance
composed of resistive and capacitive components.
The values of body impedance depend on a number of factors and, in particular, on current
path, on touch voltage, duration of current flow, frequency, degree of moisture of the skin,
surface area of contact, pressure exerted and temperature.
The impedance values indicated in this document result from a close examination of the
experimental results available from measurements carried out principally on corpses and on
some living persons.
Knowledge of the effects of alternating current is primarily based on the findings related to the
effects of current at frequencies of 50 Hz or 60 Hz which are the most common in electrical
installations. The values given are, however, deemed applicable over the frequency range
from 15 Hz to 100 Hz, threshold values at the limits of this range being higher than those at
50 Hz or 60 Hz. Principally the risk of ventricular fibrillation is considered to be the main
mechanism of death of fatal electrical accidents.
Accidents with direct current are much less frequent than would be expected from the number
of DC applications, and fatal electrical accidents occur only under very unfavourable
conditions, for example, in mines. This is partly due to the fact that with direct current, the let-
go of parts gripped is less difficult and that for shock durations longer than the period of the
cardiac cycle, the threshold of ventricular fibrillation is considerably higher than for alternating
current.
This basic safety publication is primarily intended for use by technical committees in the
preparation of standards in accordance with the principles laid down in IEC Guide 104 and
lSO/lEC Guide 51. It is not intended for use by manufacturers or certification bodies.
One of the responsibilities of a technical committee is, wherever applicable, to make use of
basic safety publications in the preparation of its publications. The requirements, test
methods or test conditions of this basic safety publication will not apply unless specifically
referred to or included in the relevant publications.
– 10 – IEC 60479-1:2018 IEC 2018
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.
IEC Guide 104:2010, The preparation of safety publications and the use of basic safety
publications and group safety publications
ISO/IEC Guide 51:2014, Safety aspects – Guidelines for their inclusion in standards
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 General definitions
3.1.1
longitudinal current
current flowing lengthwise through the trunk of the human body such as from hand to feet
3.1.2
transverse current
current flowing across the trunk of the human body such as from hand to hand
3.1.3
internal impedance of the human body
Z
i
impedance between two electrodes in contact with two parts of the human body, neglecting
skin impedances
Note 1 to entry: For the body of livestock, the impedance of the hooves, if any, are also neglected.
3.1.4
impedance of the skin
Z
s
impedance between an electrode on the skin and the conductive tissues underneath
3.1.5
total impedance of the human body
Z
T
vectorial sum of the internal impedance and the impedances of the skin
Note 1 to entry: For the body of livestock, Z is the vectorial sum of the internal impedance and the impedances
T
of the hide, skin and hooves, if any (see Figure H.1).
SEE: Figure 1.
IEC 60479-1:2018 IEC 2018 – 11 –
3.1.6
impedance of the hide and skin
Z
P
impedance between an electrode on the hide and/or skin and the conductive tissues
underneath
3.1.7
impedance of the hoof
Z
h
impedance between an electrode under the hoof and the conductive tissues above it
3.1.8
initial resistance of the human body
R
resistance limiting the peak value of the current at the moment when the touch voltage occurs
Note 1 to entry: For the body of livestock the resistance of the hide, if any, is neglected, but the resistance of the
hooves, if any, are included.
3.1.9
dry condition
condition of the skin of a surface area of contact with regard to humidity of a living person
being at rest under normal indoor environmental conditions
3.1.10
water-wet condition
condition of the skin of a surface area of contact being exposed for 1 min to water of public
water supplies (average resistivity ρ = 3 500 Ωcm, pH = 7 to 9)
3.1.11
saltwater-wet condition
condition of the skin of a surface area of contact being exposed for 1 min to a 3 % solution of
NaCl in water (average resistivity ρ = 30 Ωcm, pH = 7 to 9)
Note 1 to entry: It is assumed that saltwater-wet condition simulates the condition of the skin of a sweating person
or a person after immersion in seawater. Further investigations are necessary.
3.1.12
deviation factor
F
D
total body impedance Z for a given percentile rank of a population divided by the total body
T
impedance Z for a percentile rank of 50 % of a population at a given touch voltage
T
Z (X%, U )
T T
F (X%, U ) =
D T
Z (50%, U )
T T
3.2 Effects of sinusoidal alternating current in the range 15 Hz to 100 Hz
3.2.1
threshold of perception
minimum value of touch current which causes any sensation for the person through which it is
flowing
3.2.2
threshold of reaction
minimum value of touch current which causes involuntary muscular contraction
– 12 – IEC 60479-1:2018 IEC 2018
3.2.3
threshold of let-go
maximum value of touch current at which a person holding electrodes can let go of the
electrodes
3.2.4
threshold of immobilization
minimum value of current through the body of the influenced human being or livestock (or part
of the human body or livestock) which causes such muscular reaction that the person or
livestock cannot move voluntarily, as long as the current flows
3.2.5
threshold of ventricular fibrillation
minimum value of touch current through the body of the human being or livestock which
causes ventricular fibrillation
3.2.6
heart-current factor
F
factor which relates the electric field strength (current density) in the heart for a given current
path to the electric field strength (current density) in the heart for a touch current of equal
magnitude flowing from left hand to feet
Note 1 to entry: In the heart, the current density is proportional to the electric field strength.
3.2.7
vulnerable period
comparatively small part of the cardiac cycle during which the heart fibres are in an
inhomogeneous state of excitability and ventricular fibrillation occurs if they are excited by an
electric current of sufficient magnitude
Note 1 to entry: The vulnerable period corresponds to the first part of the T-wave in the electrocardiogram which
is approximately 10 % of the cardiac cycle (see Figures 17 and 18).
3.3 Effects of direct current
3.3.1
total body resistance
R
T
sum of the internal resistance of the human body and the resistances of the skin
3.3.2
DC/AC equivalence factor
k
ratio of direct current to its equivalent RMS value of alternating current having the same
probability of inducing ventricular fibrillation
Note 1 to entry: As an example for shock durations longer than the period of one cardiac cycle and 50 %
probability for ventricular fibrillation, the equivalence factor for 10 s is approximately:
I
300 mA
DC-fibrillation
3, 75
k = (see Figures 20 and 22).
I 80 mA
AC-fibrillation (RMS)
3.3.3
upward current
direct touch current through the human body for which the feet represent the positive polarity
==
IEC 60479-1:2018 IEC 2018 – 13 –
3.3.4
downward current
direct touch current through the human body for which the feet represent the negative polarity
4 Electrical impedance of the human body and livestock
4.1 General
The values of body impedance depend on a number of factors and, in particular, on current
path, on touch voltage, duration of current flow, frequency, degree of moisture of the skin,
surface area of contact, pressure exerted and temperature.
A schematic diagram for the impedance of the human body is shown in Figure 1.
NOTE A modelling circuit for the human body is given in Annex G.
4.2 Internal impedance of the human body (Z )
i
The internal impedance of the human body can be considered as mostly resistive. Its value
depends primarily on the current path and, to a lesser extent, on the surface area of contact.
NOTE 1 Measurements indicate that a small capacitive component exists (dashed lines in Figure 1).
Figure 2 shows the internal impedance of the human body for its different parts expressed as
percentages of that related to the path hand to foot.
For current paths hand to hand or hand to feet, the impedances are mainly located in the
limbs (arms and legs). If the impedance of the trunk of the body is neglected, a simplified
circuit diagram can be established which is shown in Figure 3.
NOTE 2 In order to simplify the circuit diagram, it is assumed that the impedance of arms and legs have the same
values.
4.3 Impedance of the skin (Z )
s
The impedance of the skin can be considered as a network of resistances and capacitances.
Its structure is made up of a semi-insulating layer and small conductive elements (pores). The
skin impedance falls when the current is increased. Sometimes current marks are observed
(see 4.7).
The value of the impedance of the skin depends on voltage, frequency, duration of the current
flow, surface area of contact, pressure of contact, the degree of moisture of the skin,
temperature and type of skin.
For lower touch voltages the value of the impedance of the skin varies widely, even for one
person, with surface area of contact and condition (dry, wet, perspiration), temperature, rapid
respiration, etc. For higher touch voltages the skin impedance decreases considerably and
becomes negligible when the skin breaks down.
As regards the influence of frequency, the impedance of the skin decreases when the
frequency increases.
)
4.4 Total impedance of the human body (Z
T
The total impedance of the human body consists of resistive and capacitive components.
For lower touch voltages, there are considerable variations in the impedance of the skin Z
S
and the total impedance of the human body Z similarly varies widely. For higher touch
T
voltages, the total impedance depends less and less on the impedance of the skin and its
value approaches that of the internal impedance Z . See Figures 4 to 9.
i
– 14 – IEC 60479-1:2018 IEC 2018
As regards the influence of frequency, taking into account the frequency dependence of the
skin impedance, the total impedance of the human body is higher for direct current and
decreases when the frequency increases.
4.5 Factors affecting initial resistance of the human body (R )
At the moment when the touch voltage occurs, capacitances in the human body are not
charged. Therefore skin impedances Z and Z are negligible and the initial resistance R is
S1 S2 0
approximately equal to the internal impedance of the human body Z (see Figure 1). The initial
i
resistance R depends mainly on the current path and to a lesser extent on the surface area
of contact.
The initial resistance R limits the current peaks of short impulses (e.g. shocks from electric
fence controllers).
4.6 Values of the total impedance of the human body (Z )
T
4.6.1 Total body impedance dependence for large, medium and small surface areas
of contact
th
The dependence of the total body impedance Z for the 50 percentile of a population of
T
living human beings for large, medium and small surface areas of contact (order of magnitude
2 2 2
10 000 mm , 1 000 mm and 100 mm respectively) in dry, water-wet and saltwater-wet
conditions at touch voltages U = 25 V AC to 200 V AC is shown in Figures 7, 8 and 9.
T
4.6.2 Sinusoidal alternating current 50/60 Hz for large surface areas of contact
The values of the total body impedances in
...
SL O V EN S K I SIST IEC 60479-1
S T ANDAR D junij 2020
Vplivi električnega toka na ljudi in živali – 1. del: Splošno
Effects of current on human beings and livestock – Part 1: General aspects
Referenčna oznaka
ICS 13.200; 29.020 SIST IEC 60479-1:2020 (sl)
Nadaljevanje na straneh od 2 do 70
© 2023-10. Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno.
SIST IEC 60479-1 : 2020
NACIONALNI UVOD
Standard SIST IEC 60479-1 (sl), Vplivi električnega toka na ljudi in živali – 1. del: Splošno, 2020, ima
status slovenskega standarda in je istoveten mednarodnemu standardu IEC 60479-1 (en), Effects of
current on human beings and livestock – Part 1: General aspects, 2018.
NACIONALNI PREDGOVOR
Mednarodni standard IEC 60479-1:2018 je pripravil tehnični odbor IEC/TC 64 Električne inštalacije in
zaščita pred električnim šokom.
Slovenski standard SIST IEC 60479-1:2020 je prevod mednarodnega standarda IEC 60479-1:2018. V
primeru spora glede besedila slovenskega prevoda v tem standardu je odločilen izvirni mednarodni
standard v angleškem jeziku. Slovensko izdajo standarda je potrdil tehnični odbor SIST/TC ELI
Nizkonapetostne in komunikacijske električne inštalacije.
Odločitev za privzem tega standarda je junija 2020 sprejel tehnični odbor SIST/TC ELI Nizkonapetostne
in komunikacijske električne inštalacije.
OSNOVA ZA IZDAJO STANDARDA
– privzem standarda IEC 60479-1:2018
OPOMBI
– Povsod, kjer se v besedilu standarda uporablja izraz “mednarodni standard”, v SIST IEC 60479-
1:2020 to pomeni “slovenski standard”.
– Nacionalni uvod in nacionalni predgovor nista sestavna dela standarda.
SIST IEC 60479-1 : 2020
VSEBINA Stran
Predgovor . 7
Uvod . 9
1 Področje uporabe .10
2 Zveze s standardi .10
3 Izrazi in definicije .11
3.1 Splošne definicije .11
3.2 Učinki sinusnega izmeničnega toka v območju 15 Hz do 100 Hz .12
3.3 Učinki enosmernega toka .13
4 Električna impedanca telesa človeka in živali .13
4.1 Splošno .13
4.2 Notranja impedanca človeškega telesa (Z ) .13
i
4.3 Impedanca kože (ZS) .14
4.4 Celotna impedanca človeškega telesa (ZT) .14
4.5 Dejavniki, ki vplivajo na začetno upornost človeškega telesa (R ) .14
4.6 Vrednosti celotne impedance človeškega telesa (ZT) .14
4.6.1 Odvisnost celotne impedance za velike, srednje in majhne stične površine .14
4.6.2 Sinusni izmenični tok, 50/60 Hz, za velike stične površine .15
4.6.3 Sinusni izmenični tok, 50/60 Hz, za srednje in majhne stične površine .17
4.6.4 Sinusni izmenični tok s frekvencami do 20 kHz in več .20
4.6.5 Enosmerni tok .21
4.7 Vrednost začetne upornosti človeškega telesa (R0) .21
4.8 Karakteristika impedance telesa živali .22
5 Učinki sinusnega izmeničnega toka v območju 15 Hz do 150 Hz .22
5.1 Splošno .22
5.2 Prag zaznavanja .22
5.3 Prag odziva .22
5.4 Otrpnjenje .22
5.5 Prag sprostitve .22
5.6 Prag ventrikularne fibrilacije .23
5.7 Drugi učinki v povezavi z električnimi udari .23
5.8 Učinek toka na kožo .24
5.9 Opis con čas/tok (glej sliko 20) .24
5.10 Uporaba faktorja toka skozi srce (F) .24
6 Učinki enosmernega toka .25
6.1 Splošno .25
6.2 Prag zaznavanja in prag odziva .25
6.3 Prag otrpnjenja in prag sprostitve .26
6.4 Prag ventrikularne fibrilacije .26
6.5 Drugi učinki toka .26
SIST IEC 60479-1 : 2020
6.6 Opis con čas/tok (glej sliko 22) .26
6.7 Faktor srca .27
6.8 Učinki anodnih enosmernih tokov proti katodnim .45
Dodatek A (normativni): Meritve celotnih impedanc telesa Z , izvedene na živih ljudeh in truplih,
T
ter statistična analiza rezultatov .47
Dodatek B (normativni): Vpliv frekvence na celotno impedanco telesa (Z ) .50
T
Dodatek C (normativni): Celotna upornost telesa (R ) za enosmerni tok .51
T
Dodatek D (informativni): Primeri izračunov ZT .52
Dodatek E (informativni): Teorije ventrikularne fibrilacije .55
Dodatek F (informativni): Veličine za zgornjo mejo ranljivosti (ULV) in
spodnjo mejo ranljivosti (LLV) .56
Dodatek G (informativni) Metode simulacije tokokrogov pri oceni električnega udara .57
Dodatek H (normativni) Učinki tokov, ki tečejo skozi telo živali .60
H.1 Splošno .60
H.2 Glavni dejavnik tveganja ventrikularne fibrilacije za živali .60
H.3 Karakteristika impedance telesa živali .61
H.4 Notranja impedanca živali (Z ) .61
i
H.5 Impedanca dlakave in gole kože (Z ) .62
P
H.6 Impedanca (upornost) kopit/parkljev (Z , R ) .62
h h
H.7 Celotna impedanca telesa (Z ) .62
T
H.8 Začetna upornost telesa (R ) .62
H.9 Vrednosti celotne impedance telesa (Z .63
T
H.10 Vrednosti začetne upornosti telesa (R ) .64
H.11 Učinki sinusnega izmeničnega toka v območju od 15 Hz do 100 Hz na živali .64
H.11.1 Splošno .64
H.11.2 Prag odziva .64
H.11.3 Prag ventrikularne fibrilacije .64
Literatura .67
Slika 1: Impedance človeškega telesa .27
Slika 2: Notranje delne impedance Z človeškega telesa .28
ip
Slika 3: Poenostavljena shema notranjih impedanc človeškega telesa .29
Slika 4: Celotna impedanca telesa Z (50 %) za pot toka roka–roka za velike suhe, mokre in
T
slano-mokre stične površine za 50 % populacije za napetosti dotika U = 25 V do 700 V,
T
izmenični tok, 50/60 Hz .30
Slika 5: Odvisnost celotne impedance Z ene žive osebe od suhe stične površine in pri napetosti
T
dotika (50 Hz) .31
Slika 6: Odvisnost celotne impedance telesa Z od napetosti dotika U za pot toka od konice
T T
desnega kazalca do konice levega kazalca v primerjavi z velikimi suhimi stičnimi površinami pri
poti toka od leve roke do desne roke, merjeno na eni živi osebi, napetost dotika v območju
UT = 25 V do 200 V, izmenični tok, 50 Hz, trajanje toka največ 25 ms .32
Slika 7: Odvisnost celotne impedance telesa Z za 50-odstotkovni nivo populacije živih ljudi
T
2 2
za velike, srednje in majhne suhe stične površine (red velikosti 10 000 mm , 1 000 mm oziroma
100 mm ) pri napetostih dotika U = 25 V do 200 V, izmenični tok, 50/60 Hz .33
T
SIST IEC 60479-1 : 2020
Slika 8: Odvisnost celotne impedance telesa Z za 50-odstotkovni nivo populacije živih ljudi za
T
2 2
velike, srednje in majhne mokre stične površine (red velikosti 10 000 mm , 1 000 mm oziroma
100 mm ) pri napetostih dotika U = 25 V do 200 V, izmenični tok, 50/60 Hz .34
T
za 50-odstotkovni nivo populacije živih ljudi za
Slika 9: Odvisnost celotne impedance telesa ZT
2 2
velike, srednje in majhne slano-mokre stične površine (red velikosti 10 000 mm , 1 000 mm in
100 mm ) pri napetostih dotika UT = 25 V do 200 V, izmenični tok, 50/60 Hz .35
Slika 10: Vrednosti celotne impedance telesa Z , merjeno na 10 živih ljudeh s potjo toka
T
roka–roka in velikimi suhimi stičnimi površinami pri napetosti dotika 10 V in
frekvencah od 25 Hz do 20 kHz .36
Slika 11: Vrednosti celotne impedance telesa Z , merjeno na enem živem človeku s potjo toka
T
roka–roka in velikimi suhimi stičnimi površinami ter pri napetosti dotika 25 V in
frekvencah od 25 Hz do 2 kHz .36
Slika 12: Frekvenčna odvisnost celotne impedance telesa Z za 50-odstotkovni nivo populacije
T
pri napetostih dotika od 10 V do 1 000 V in frekvenčnem območju od 50 Hz do 150 kHz za
pot toka roka–roka ali roka–stopalo, za velike suhe stične površine .37
Slika 13: Statistična vrednost celotne impedance telesa Z in upornosti telesa R za
T T
50-odstotkovni nivo populacije živih ljudi za pot toka roka–roka, velike suhe stične površine,
pri napetostih dotika do vključno 700 V, za izmenični tok, 50/60 Hz, in enosmerni tok .37
Slika 14: Odvisnost spreminjanja stanja človeške kože od gostote toka i in trajanja toka .38
T
Slika 15: Elektrode, uporabljene za meritev odvisnosti impedance človeškega telesa Z
T
od stične površine .39
Slika 16: Oscilogrami napetosti U in tokov dotika I za izmenični tok, pot toka roka–roka, velike suhe
T T
stične površine, dobljeno z meritvami .40
Slika 17: Pojav obdobja ranljivosti prekatov v srčnem ciklu .41
Slika 18: Proženje ventrikularne fibrilacije v obdobju ranljivosti – učinki na elektrokardiogramu
(EKG) in krvnem tlaku .41
Slika 19: Podatki fibrilacije za pse, prašiče in ovce iz poskusov in za osebe, izračunani iz statistik
nesreč z elektriko s tokom v prečni smeri roka–roka in napetostma dotika UT = 220 V in 380 V
izmenično z impedancami telesa Z (5 %) .42
T
Slika 20: Splošno sprejete cone čas/tok za učinke izmeničnih tokov (15 Hz do 100 Hz) na osebe
za pot toka, ki ustreza poti leva roka–stopala (glej preglednico 11) .43
Slika 21: Oscilogram napetosti dotika U in toka dotika I za enosmerni tok,
T T
pot toka roka–roka, velike suhe stične površine .43
Slika 22: Splošno sprejete cone čas/tok za učinke enosmernih tokov na osebe za vzdolžno
pot toka navzgor (glej preglednico 13) .44
Slika 23: Toki sprostitve za sinusni tok, 60 Hz .44
Slika 24: Učinki anodnih enosmernih tokov proti katodnim .45
Slika 25: Stimulacija udarov enosmernega toka posameznih srčnih celic .46
Slika G.1: Električni udar v električnem modelu po Hartu [33], vključno z učinkom odziva na strah .58
Slika H.1: Potek toka in impedanc ustreznih delov telesa krave za pot toka od gobca do nog .61
Slika H.2: Shemi za žival, za pot toka od gobca do štirih nog (pot A) in od sprednjih nog
do zadnjih (pot B) .61
Slika H.3: Shema celotne impedance telesa goveda za 5 % populacije .63
Slika H.4: Ventrikularna fibrilacija pri ovcah .65
Slika H.5: Najmanjši tok fibrilacije pri ovcah kot funkcija mase za trajanje udara 3 s [55] .66
Slika H.6: Najmanjši toki fibrilacije (povprečja) različnih vrst živali kot funkcija mase za čas trajanja
udara 3 s [53] .66
SIST IEC 60479-1 : 2020
Preglednica 1: Celotne impedance telesa ZT za pot toka roka–roka, izmenični tok, 50/60 Hz,
za velike suhe stične površine .15
Preglednica 2: Celotne impedance telesa Z za pot toka roka–roka, izmenični tok, 50/60 Hz,
T
za velike mokre stične površine .16
Preglednica 3: Celotne impedance telesa ZT za pot toka roka–roka, izmenični tok, 50/60 Hz,
za velike slano-mokre stične površine .17
Preglednica 4: Celotne impedance telesa Z za pot toka roka–roka za srednje suhe stične
T
površine pri napetostih dotika UT = 25 V do 200 V, izmenični tok, 50/60 Hz (vrednosti so
zaokrožene na 25 Ω) .18
Preglednica 5: Celotne impedance telesa ZT za pot toka roka–roka za srednje mokre stične
površine pri napetostih dotika U = 25 V do 200 V, izmenični tok, 50/60 Hz (vrednosti so
T
zaokrožene na 25 Ω) .19
Preglednica 6: Celotne impedance telesa ZT za pot toka roka–roka za srednje slano-mokre
stične površine pri napetostih dotika U = 25 V do 200 V, izmenični tok, 50/60 Hz
T
(vrednosti so zaokrožene na 5 Ω) .19
Preglednica 7: Celotne impedance telesa ZT za pot toka roka–roka za majhne suhe stične površine
pri napetostih dotika U = 25 V do 200 V, izmenični tok, 50/60 Hz (vrednosti so zaokrožene
T
na 25 Ω) .19
Preglednica 8: Celotne impedance telesa ZT za pot toka roka–roka za majhne mokre stične površine
pri napetostih dotika U = 25 V do 200 V, izmenični tok, 50/60 Hz (vrednosti so zaokrožene
T
na 25 Ω) .20
Preglednica 9: Celotne impedance telesa Z za pot toka roka–roka za majhne slano-mokre
T
stične površine pri napetostih dotika UT = 25 V do 200 V, izmenični tok, 50/60 Hz
(vrednosti so zaokrožene na 5 Ω) . 20
Preglednica 10: Celotne upornosti telesa R za pot toka roka–roka, enosmerni tok, za velike
T
suhe stične površine .21
Preglednica 11: Cone čas/tok za izmenični tok, 15 Hz do 100 Hz, za pot roka–stopala –
povzetek con s slike 20 .24
Preglednica 12: Faktor toka skozi srce F za različne poti toka .25
Preglednica 13: Cone čas/tok za enosmerni tok za pot roka–stopala – povzetek con s slike 22 .27
Preglednica A.1: Celotne impedance telesa Z , elektrode tipa A za suhe pogoje in faktorja
T
odstopanja F (5 % in 95 %) .47
D
Preglednica A.2: Celotna impedanca telesa Z , elektrode tipa B za suhe, mokre in slano-mokre
T
pogoje ter faktorja odstopanja F (5 % in 95 %) .47
D
Preglednica A.3: Celotne impedance telesa Z za suhe, mokre in slano-mokre pogoje ter
T
faktorja odstopanja F (5 % in 95 %) .48
D
Preglednica A.4: Faktorja odstopanja F (5 %) in F (95 %) pri napetostih dotika v območju
T D
U = 25 V do vključno 400 V za velike, srednje in majhne suhe in mokre stične površin .49
T
Preglednica D.1: 50-odstotkovne vrednosti za celotno impedanco telesa za pot toka
roke–stopala, srednja suha stična površina za roke, velika suha stična površina za stopala,
faktor znižanja 0,8, toki dotika I in elektrofiziološki učinki .53
T
Preglednica G.1: Primeri impedance telesa (nekompenzirani) .58
Preglednica H.1: Impedanca (upornost) parkljev govedi (Z , R ) za izmenične napetosti do vključno
h h
230 V, 50/60 Hz .62
Preglednica H.2: Celotne impedance telesa Z za izmenični tok, 50/60 Hz, za govedo pri
T
napetostih dotika do vključno 230 V .63
Preglednica H.3: Začetna upornost telesa R za govedo .64
Preglednica H.4: Prag ventrikularne fibrilacije pri izmeničnem toku, 50/60 Hz [53] [54],
za različne vrste živali in trajanje udara 3 s .65
SIST IEC 60479-1 : 2020
MEDNARODNA ELEKTROTEHNIŠKA KOMISIJA
VPLIVI TOKA NA LJUDI IN ŽIVALI –
1. del: Splošni vidiki
Predgovor
1. Mednarodna elektrotehniška komisija (IEC) je svetovna organizacija za standardizacijo, ki združuje vse nacionalne
elektrotehnične komiteje (nacionalni komiteji IEC). Cilj IEC je pospeševati mednarodno sodelovanje v vseh vprašanjih
standardizacije s področja elektrotehnike in elektronike. V ta namen poleg drugih aktivnosti izdaja mednarodne standarde,
tehnične specifikacije, tehnična poročila, javno dostopne specifikacije (PAS) in vodila (v nadaljevanju: publikacije IEC). Za
njihovo pripravo so odgovorni tehnični odbori; vsak nacionalni komite IEC, ki ga zanima obravnavana tema, lahko sodeluje
v tem pripravljalnem delu. Prav tako lahko v pripravi sodelujejo mednarodne organizacije ter vladne in nevladne ustanove,
ki so povezane z IEC. IEC deluje v tesni povezavi z mednarodno organizacijo za standardizacijo ISO skladno s pogoji,
določenimi v soglasju med obema organizacijama.
2. Uradne odločitve ali sporazumi IEC o tehničnih vprašanjih, pripravljeni v tehničnih odborih, kjer so prisotni vsi nacionalni
komiteji, ki jih tema zanima, izražajo, kolikor je mogoče, mednarodno soglasje o obravnavani temi.
3. Publikacije IEC imajo obliko priporočil za mednarodno uporabo ter jih kot takšne sprejmejo nacionalni komiteji IEC. Čeprav
IEC skuša zagotavljati natančnost tehničnih vsebin v publikacijah IEC, IEC ni odgovoren za način uporabe ali za možne
napačne interpretacije končnih uporabnikov.
4. Da bi se pospeševalo mednarodno poenotenje, so nacionalni komiteji IEC v svojih nacionalnih in regionalnih standardih
dolžni čim pregledneje uporabljati mednarodne standarde. Vsako odstopanje med standardom IEC in ustreznim
nacionalnim ali regionalnim standardom je treba v slednjem jasno označiti.
5. IEC sam ne izvaja potrjevanja skladnosti. Storitve ugotavljanja skladnosti in na nekaterih območjih tudi dostop do znakov
skladnosti IEC izvajajo neodvisni certifikacijski organi. IEC ni določil nobenega postopka v zvezi z označevanjem kot znakom
strinjanja in ne prevzema nikakršne odgovornosti za storitve, ki jih izvajajo neodvisni certifikacijski organi.
6. Vsi uporabniki naj bi si zagotovili zadnjo izdajo teh publikacij.
7. IEC ali njegovi direktorji, zaposleni, uslužbenci ali agenti, vključno s samostojnimi strokovnjaki ter člani tehničnih odborov
in nacionalnih komitejev IEC, ne prevzemajo nobene odgovornosti za kakršnokoli osebno poškodbo, škodo na premoženju
ali katerokoli drugo škodo kakršnekoli vrste, bodisi posredne ali neposredne, ali za stroške (vključno z zakonitim lastništvom)
in izdatke, povezane s publikacijo, njeno uporabo ali zanašanjem na to publikacijo IEC ali katerokoli drugo publikacijo IEC.
8. Posebno pozornost je treba posvetiti normativnim virom, na katere se sklicuje ta publikacija. Uporaba navedenih publikacij
je nujna za pravilno uporabo te publikacije.
9. Opozoriti je treba na možnost, da bi lahko bil kateri od elementov tega mednarodnega standarda predmet patentnih pravic.
IEC ne odgovarja za identifikacijo nobene od teh patentnih pravic.
Mednarodni standard IEC 60479-1 je pripravil tehnični odbor IEC/TC 64 Električne inštalacije in zaščita
pred električnim udarom.
Ta prva izdaja razveljavlja in nadomešča IEC/TS 60479-1:2005, Dopolnilo 1:2016 in IEC/TR 60479-
3:1998. Ta izdaja predstavlja tehnično spremembo.
Ta izdaja vključuje naslednje pomembne tehnične spremembe glede na IEC/TS 60479-1 in IEC/TR
60479-3:
– vsebina IEC/TR 60479-3 v zvezi z vidiki, ki so edinstveni glede učinkov toka skozi telesa živali, je
vključena v novi dodatek H (normativni).
Dokument ima status osnovne varnostne publikacije v skladu z IEC Vodilom 104.
SIST IEC 60479-1 : 2020
Besedilo tega mednarodnega standarda temelji na naslednjih dokumentih:
CDV Poročilo o glasovanju
64/2275/CDV 64/2343/RVC
Vse informacije o glasovanju za potrditev tega mednarodnega standarda so v poročilu o glasovanju,
navedenem v gornji preglednici.
Ta dokument je bil pripravljen v skladu z 2. delom Direktiv ISO/IEC.
Na spletnih straneh IEC je na voljo seznam vseh delov v skupini IEC 60479, objavljeni pod splošnim
naslovom Učinki električnega toka na ljudi in živali.
Odbor se je odločil, da bo vsebina tega dokumenta ostala nespremenjena do datuma stabilnosti, ki je
določen na spletni strani IEC "http://webstore.iec.ch" pri podatkih, vezanih na ta dokument. Po tem
datumu bo dokument:
– ponovno potrjen,
– razveljavljen,
– zamenjan z novo izdajo ali
– dopolnjen.
Dvojezična različica te publikacije je lahko izdana pozneje.
POMEMBNO: Logotip "v barvah" na platnicah te publikacije opozarja, da vsebuje barve, ki so potrebne
za pravilno razumevanje njene vsebine. Uporabniki naj zato tiskajo ta dokument z barvnim tiskalnikom.
SIST IEC 60479-1 : 2020
Uvod
Da bi se izognili napačnim interpretacijam tega dokumenta, je treba poudariti, da so podatki v njem
pridobljeni večinoma s poskusi na živalih in z razpoložljivimi informacijami iz kliničnih opazovanj. Le
nekaj preskusov udarov s kratkotrajnimi toki je bilo izvedenih na živih ljudeh.
Na podlagi razpoložljivih dokazov, v glavnem iz raziskav na živalih, so vrednosti tako konzervativne, da
velja ta dokument za osebe v normalnem fiziološkem stanju, vključno z otroki, ne glede na starost in
maso.
Tu so seveda tudi drugi vidiki, ki naj bi se upoštevali, kot so verjetnost okvar, verjetnost stika z deli pod
napetostjo ali okvarjenimi deli, razmerje med napetostjo dotika in okvarno napetostjo, pridobljene
izkušnje, tehnične možnosti in gospodarnost. Ti parametri naj se skrbno upoštevajo pri določanju
varnostnih zahtev, na primer obratovalne karakteristike zaščitnih naprav za električne inštalacije.
Oblika dokumenta, kot je bila izbrana, povzema do sedaj pridobljene rezultate, ki jih uporablja tehnični
odbor IEC/TC 64 kot podlago za postavljanje zahtev za zaščito pred električnim udarom. Za te rezultate
se šteje, da so dovolj pomembni za utemeljitev publikacije IEC, ki lahko služi kot vodilo drugim odborom
IEC in državam, ki potrebujejo take informacije.
Ta dokument velja za prag ventrikularne fibrilacije, ki je glavni vzrok smrti zaradi električnega toka.
Skupna analiza rezultatov nedavnih raziskav fiziologije srca in praga fibrilacije je omogočila boljše
razumevanje vpliva glavnih fizioloških parametrov in še posebej trajanja toka.
Ta dokument vsebuje informacijo o impedanci telesa in pragih tokov skozi telo za različne fiziološke
učinke. To informacijo je mogoče kombinirati z namenom, da se pridobijo ocene pragov izmenične in
enosmerne napetosti dotika za določene poti toka skozi telo, pogoje vlažnosti stikov in stične površine
na koži.
Ta dokument se posebej nanaša na učinke električnega toka. Pri ocenjevanju škodljivih učinkov
vsakega primera, izvedenega na ljudeh in živalih, naj se upoštevajo drugi neelektrični pojavi, vključno s
padci, vročino, ognjem in drugimi. Te zadeve so zunaj področja uporabe tega dokumenta, vendar so
lahko same po sebi izjemno resne.
V obravnavi so nadaljnji podatki preskusov, npr. nedavno preskusno delo pri "tokovno vzbujeni fibrilaciji
srca z vzbujanjem z diskretnim Fourierovim spektrom", ki je namenjeno prispevanju podatkov za
frekvenčni faktor.
Karakteristike impedance telesa živali in učinki sinusnega izmeničnega toka so opisani v dodatku H.
SIST IEC 60479-1 : 2020
Učinki toka na ljudi in živali – 1. del: Splošni vidiki
1 Področje uporabe
Te del IEC 60479 zagotavlja osnovne napotke o učinkih udarnega toka na ljudi in živali.
Nevarnost za osebe je v glavnem odvisna od velikosti in trajanja toka za dano pot toka skozi človeško
telo. Vendar cone čas/tok, ki so podane v naslednjih poglavjih, v mnogih primerih niso neposredno
uporabne v praksi za zasnovo ukrepov za zaščito pred električnim udarom. Potrebno merilo je dopustna
meja za napetost dotika (tj. zmnožek toka skozi telo, imenovanega tok dotika, in impedance telesa) kot
funkcije časa. Razmerje med tokom in napetostjo ni linearno, ker se impedanca človeškega telesa
spreminja z napetostjo dotika, in so zato potrebni podatki o tem razmerju. Različni deli človeškega telesa
(kot so koža, kri, mišice, druga tkiva in sklepi) predstavljajo električnemu toku določeno impedanco,
sestavljeno iz uporovnih in kapacitivnih sestavin.
Vrednosti impedance telesa so odvisne od številnih dejavnikov in še posebej od poti toka, napetosti
dotika, trajanja toka, frekvence, stopnje vlažnosti kože, stične površine, uporabljenega pritiska in
temperature.
V tem dokumentu prikazane vrednosti impedanc izhajajo iz natančnih pregledov eksperimentnih
rezultatov, pridobljenih iz meritev, izvedenih v glavnem na truplih in nekatere na živih osebah.
Poznavanje učinkov izmeničnega toka najprej temelji na odkritjih v zvezi z učinki toka s frekvenco 50 Hz
ali 60 Hz, ki sta najbolj običajni pri električnih inštalacijah. Vendar se šteje, da so dane vrednosti
uporabne v frekvenčnem območju od 15 Hz do 100 Hz in da so vrednosti praga na mejah tega območja
višje kot pri 50 Hz ali 60 Hz. Načelno se tveganje za ventrikularno fibrilacijo obravnava kot glavni
mehanizem smrtnih nesreč pri delu z elektriko.
Nesreče z enosmernim tokom so mnogo redkejše, kot bi jih lahko pričakovali glede na število
enosmernih aplikacij, in usodne nesreče z elektriko se zgodijo samo v zelo neugodnih pogojih, na primer
v rudnikih. Delni razlog je dejstvo, da je pri enosmernem toku sprostitev oprijema manj zahtevna in da
je pri trajanju udara, ki je daljše od ene periode srčnega ciklusa, prag ventrikularne fibrilacije znatno višji
od praga za izmenični tok.
Ta osnovna varnostna publikacija je primarno namenjena tehničnim odborom za pripravo standardov
skladno z načeli, ki so podani v IEC Vodilu 104 in lSO/lEC Vodilu 51. Ni namenjena za uporabo pri
proizvajalcih ali certifikacijskih organih.
Ena od odgovornosti tehničnega odbora je, kjerkoli je uporabno, zagotoviti uporabo osnovnih publikacij
pri pripravi lastnih publikacij. Zahteve, preskusne metode ali preskusni pogoji te osnovne varnostne
publikacije pa veljajo samo v primeru sklicevanja nanje v ustreznih publikacijah.
2 Zveze s standardi
Za uporabo tega standarda so, delno ali v celoti, nujno potrebni spodaj navedeni dokumenti. Pri datiranih
sklicevanjih se uporablja le navedena izdaja. Pri nedatiranih sklicevanjih se uporablja zadnja izdaja
publikacije (vključno z dopolnili).
IEC Vodilo 104:2010 Priprava varnostnih publikacij in uporaba osnovnih varnostnih publikacij in
skupinskih varnostnih publikacij
ISO/IEC Vodilo 51:2014 Varnostni vidiki – Smernice za njihovo vključenost v standarde
SIST IEC 60479-1 : 2020
3 Izrazi in definicije
V tem dokumentu se uporabljajo naslednji izrazi in definicije.
ISO in IEC hranita terminološke zbirke podatkov za uporabo v standardizaciji na naslednjih naslovih:
– IEC Electropedia: na voljo na spletnem mestu http://www.electropedia.org/
– platforma za brskanje po spletu ISO: na voljo na spletnem mestu http://www.iso.org/obp
3.1 Splošne definicije
3.1.1
vzdolžni tok
tok, ki teče vzdolž trupa človeškega telesa, na primer smer roka–stopala
3.1.2
prečni tok
tok, ki teče prečno skozi trup človeškega telesa, na primer roka–roka
3.1.3
notranja impedanca človeškega telesa
Z
i
impedanca med dvema elektrodama v stiku z dvema deloma človeškega telesa, pri čemer so
zanemarjene impedance kože
Opomba 1: Pri telesu živali so impedance parkljev/kopit, če so, prav tako zanemarjene.
3.1.4
impedanca kože
Z
S
impedanca med elektrodo na koži in prevodnimi tkivi pod njo
3.1.5
celotna impedanca človeškega telesa
Z
T
vektorska vsota notranje impedance in impedanc kože
Opomba 1: Pri telesu živali je Z vektorska vsota notranje impedance in impedanc dlakave in gole kože ter parkljev/kopit, če
T
so (glej sliko H.1).
GLEJ: slika 1.
3.1.6
impedanca dlakave in gole kože
Z
P
impedanca med elektrodo na dlakavi in/ali goli koži in prevodnimi tkivi pod njo
3.1.7
impedanca parkljev/kopit (v nadaljevanju: parklji)
Z
h
impedanca med elektrodo pod parkljem in prevodnim tkivom nad njim
3.1.8
začetna upornost človeškega telesa
R
upornost, ki omeji temensko vrednost toka v trenutku, ko se pojavi napetost dotika
Opomba 1: Pri telesu živali se zanemari upornost dlakave kože, če je, vendar pa je vključena upornost parkljev, če so.
SIST IEC 60479-1 : 2020
3.1.9
suhi pogoji
stanje stične površine kože glede na vlažnost žive osebe, ki miruje pri normalnih notranjih okoljskih
pogojih
3.1.10
mokri pogoji
stanje stične površine kože, ki je bila za 1 min izpostavljena vodi iz javnega vodovoda (povprečna
specifična upornost ρ = 3 500 Ωcm, pH = 7 do 9)
3.1.11
slano-mokri pogoji
stanje stične površine kože, ki je bila za 1 min izpostavljena 3-odstotni raztopini NaCl v vodi (povprečna
specifična upornost ρ = 30 Ωcm, pH = 7 do 9)
Opomba 1: Predpostavlja se, da slano-mokri pogoji simulirajo stanje kože prepotene osebe ali osebe po potopu v morsko
vodo. Potrebne so dodatne preiskave.
3.1.12
faktor odstopanja
F
D
celotna impedanca telesa ZT za dani odstotkovni nivo populacije, deljena s celotno impedanco telesa ZT
za odstotkovni nivo 50 % populacije pri dani napetosti dotika
3.2 Učinki sinusnega izmeničnega toka v območju 15 Hz do 100 Hz
3.2.1
prag zaznavanja
najmanjša vrednost toka dotika, ki ga še zazna oseba, skozi katero teče
3.2.2
prag odziva
najmanjša vrednost toka dotika, ki povzroči nenamerno krčenje mišic
3.2.3
prag sprostitve
največja vrednost toka dotika, pri kateri lahko oseba, ki drži elektrodi, še spusti ti elektrodi
3.2.4
prag otrpnjenja
najmanjša vrednost toka skozi telo človeka ali živali, na katero vpliva (ali skozi del človeškega telesa ali
živali), ki povzroči tak odziv mišic, da se oseba ali žival ne more prosto premikati, dokler teče tok
3.2.5
prag ventrikularne fibrilacije
najmanjša vrednost toka dotika skozi telo človeka ali živali, ki povzroči ventrikularno fibrilacijo
3.2.6
faktor toka skozi srce
F
faktor, ki se nanaša na električno poljsko jakost (tokovno gostoto) v srcu za dano tokovno pot glede na
električno poljsko jakost (tokovno gostoto) v srcu za tok dotika enake velikosti, ki teče iz leve roke v
stopala
SIST IEC 60479-1 : 2020
Opomba 1: V srcu je tokovna gostota sorazmerna z električno poljsko jakostjo.
3.2.7
obdobje ranljivosti
primerljivo majhen del srčnega ciklusa, v katerem so srčna mišična vlakna v nehomogenem stanju
vzdražljivosti in se pojavi ventrikularna fibrilacija, če se pojavi dovolj velik električni tok
Opomba 1: Obdobje ranljivosti ustreza prvemu delu T-vala v elektrokardiogramu, ki je približno 10 % srčnega cikla (glej sliki
17 in 18).
3.3 Učinki enosmernega toka
3.3.1
celotna upornost telesa
RT
vsota notranje upornosti človeškega telesa in upornosti kože
3.3.2
faktor ekvivalence DC/AC
k
razmerje enosmernega toka in ekvivalentne efektivne vrednosti izmeničnega toka, ki ima enako
verjetnost povzročitve ventrikularne fibrilacije
Opomba 1: Na primer, pri trajanjih šoka, daljših od enega srčnega cikla, in pri 50-odstotni verjetnosti ventrikularne fibrilacije
je faktor ekvivalence za 10 s približno:
𝐼𝐼
300 𝑚𝑚𝑚𝑚
𝐷𝐷𝐷𝐷−𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓
𝑘𝑘 = = = 3,75 (glej sliki 20 in 22)
𝐼𝐼 80 𝑚𝑚𝑚𝑚
𝐴𝐴𝐷𝐷−𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 (𝑅𝑅𝑅𝑅𝑅𝑅)
3.3.3
tok navzgor
enosmerni tok dotika skozi človeško telo, pri katerem stopala predstavljajo pozitivni pol
3.3.4
tok navzdol
enosmerni tok dotika skozi človeško telo, pri katerem stopala predstavljajo negativni pol
4 Električna impedanca telesa človeka in živali
4.1 Splošno
Vrednost impedance telesa je odvisna od številnih dejavnikov in še posebej od poti toka, napetosti
dotika, trajanja toka, frekvence, stopnje vlažnosti kože, stične površine, uporabljenega pritiska in
temperature.
Načrt za impedanco človeškega telesa ja prikazan na sliki 1.
OPOMBA: Modelno vezje za človeško telo je podano v dodatku G.
4.2 Notranja impedanca človeškega telesa (Z )
i
Notranja impedanca človeškega telesa se lahko obravnava predvsem kot uporovna. Njena vrednost je
najprej odvisna od poti toka in v manjši meri od površine.
OPOMBA 1: Meritve kažejo, da obstaja majhen kapacitivni delež (črtkane črte v sliki 1).
Slika 2 kaže notranjo impedanco za različne dele človeškega telesa, izraženo v odstotkih glede na pot
toka roka–stopalo.
SIST IEC 60479-1 : 2020
Pri poteh toka roka–roka ali roka–stopala so impedance v glavnem postavljene predvsem v okončine
(roke in noge). Če se zanemari impedanca trupa telesa, se lahko ustvari poenostavljena shema
tokokroga, ki je prikazana na sliki 3.
OPOMBA 2: Za poenostavitev sheme tokokroga je privzeto, da imajo impedance rok in nog enake vrednosti.
4.3 Impedanca kože (ZS)
Impedanca kože se lahko obravnava kot omrežje upornosti in kapacitivnosti. Koža je zgrajena iz
polizolirne plasti in malih prevodnih elementov (pore). Impedanca kože pada, ko se tok veča. Včasih se
opazijo sledi toka (glej 4.7).
Vrednost impedance kože je odvisna od napetosti, frekvence, trajanja toka, stične površine, pritiska na
stik, stopnje vlažnosti kože, temperature in vrste kože.
Pri nižjih napetostih dotika se vrednost impedance kože zelo spreminja, tudi pri eni sami osebi, s stično
površino in stanjem (suho, mokro, znoj), temperaturo, naglim dihanjem itd. Pri višjih napetostih dotika
se impedanca kože znatno niža in postane zanemarljiva ob preboju kože.
Glede na vpliv frekvence se impedanca kože niža z višanjem frekvence.
4.4 Celotna impedanca človeškega telesa (Z )
T
Celotno impedanco človeškega telesa sestavljajo uporovni in kapacitivni deli.
Pri nižjih napetostih dotika se impedanca kože Z znatno spreminja in podobno celotna impedanca
S
človeškega telesa ZT. Pri višjih napetostih dotika je celotna impedanca vse manj odvisna od impedance
kože in se njena vrednost približuje vrednosti notranje impedance Z . Glej slike 4 do 9.
i
Glede na vpliv frekvence in z upoštevanjem frekvenčne odvisnosti impedance kože je celotna
impedanca človeškega telesa višja pri enosmernem toku in se niža z višanjem frekvence.
4.5 Dejavniki, ki vplivajo na začetno upornost človeškega telesa (R0)
V trenutku, ko se pojavi napetost dotika, kapacitivnosti človeškega telesa niso napolnjene. Zato sta
impedanci kože Z in Z zanemarljivi in je začetna upornost R približno enaka notranji impedanci
S1 S2 0
človeškega telesa Zi (glej sliko 1). Začetna upornost R0 je v glavnem odvisna od poti toka in v manjšem
delu od stične površine.
Začetna upornost R omeji tokovne konice kratkih udarov (npr. udarov električnega pastirja).
4.6 Vrednosti celotne impedance človeškega telesa (Z )
T
4.6.1 Odvisnost celotne impedance telesa za velike, srednje in majhne stične površine
Odvisnost celotne impedance telesa Z za 50-odstotkovno populacijo živih ljudi za velike, srednje in
T
2 2
majhne suhe, mokre in slano-mokre stične površine (red velikosti 10 000 mm , 1 000 mm oziroma
100 mm ) pri napetostih dotika U = 25 V izmenično do 200 V izmenično je prikazana na slikah 7, 8 in
T
9.
SIST IEC 60479-1 : 2020
4.6.2 Sinusni izmenični tok, 50/60 Hz, za velike stične površine
Vrednosti celotne impedance telesa v preglednicah 1, 2 in 3 veljajo za žive ljudi in pot toka roka–roka
za velike suhe (preglednica 1), mokre (preglednica 2) in slano-mokre (preglednica 3) stične površine
(red velikosti 10 000 mm ).
Na sliki 4 je predstavljeno območje celotne impedance za napetosti dotika do vključno 700 V za velike
suhe, mokre in slano-mokre stične površine za odstotkovni nivo 50 % populacije.
Vrednosti v preglednicah 1, 2 in 3 predstavljajo najboljše poznavanje celotne impedance telesa Z za
T
žive odrasle osebe. Na podlagi trenutno razpoložljivega znanja je celotna impedanca telesa ZT otrok
nekol
...
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