1、 IEC TS 62996 Edition 1.0 2017-09 TECHNICAL SPECIFICATION Industrial electroheating and electromagnetic processing equipment Requirements on touch currents, voltages and electric fields from 1 kHz to 6 MHz IEC TS 62996:2017-09(en) colour inside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2017
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11、etic processing equipment Requirements on touch currents, voltages and electric fields from 1 kHz to 6 MHz INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 25.180.10 ISBN 978-2-8322-4798-3 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this pu
12、blication from an authorized distributor. colour inside 2 IEC TS 62996:2017 IEC 2017 CONTENTS FOREWORD . 5 INTRODUCTION . 7 1 Scope 9 2 Normative references 9 3 Terms and definitions 9 4 Organization and use of this document 11 5 Prospective source voltage limits . 12 6 Assessment of the source impe
13、dance 12 7 Touching and access considerations . 13 7.1 General . 13 7.2 Primary contact areas . 13 7.3 Special protective gloves, footwear and clothing . 13 7.4 External metallic objects and tools 14 7.5 Considerations for the secondary contact area assessment 14 8 Impedances of parts of the body, a
14、nd touch current densities 14 8.1 General . 14 8.2 The equivalent circuit of skin and parts of the body . 15 8.3 Touch current density consideration for large contact areas 16 9 Capacitively coupled currents in the body due to an external electric field or insulated live part 16 9.1 General and meas
15、urement frequency 16 9.2 Determination of the capacitance 16 9.3 Assessment of the electric field and use of reference level data 17 9.4 Measurement methods and limiting values 17 9.4.1 Simplified measurement of the prospective current in the parts of the body 17 9.4.2 More accurate method for deter
16、mination of currents in the parts of the body 17 9.4.3 Limiting touch current values . 17 10 Electric shock immediate nerve and muscle reactions. 17 10.1 General . 17 10.2 Touch current limits immediate nerve and muscle reactions . 17 11 Electric shock local overheating and burns of parts of the bod
17、y 18 11.1 General and initial thermal conditions . 18 11.2 Awareness, perception and withdrawal . 19 11.2.2 Heat sensing nerves exist only in the skin region, and thus not in the interior of for example fingers. Conditions where such interior heating occurs while the skin sensing is insufficient for
18、 perception are dealt with in 11.3. 19 11.2.3 The perception conditions for hazard calculations are skin temperature rises of at least 3 K over 5 s to 10 s and 5 K over 20 s or less. These times then include the time for withdrawal. The high alternative value 10 s applies if the touching part of the
19、 body is large and less easy to withdraw (i.e. the upper arm, leg or torso) than a hand or finger for which 5 s applies. 19 11.3 Long-term tissue overheating 19 12 Requirements and risk group classification 20 12.1 General . 20 IEC TS 62996:2017 IEC 2017 3 12.2 Conditions for the touch current limit
20、s up to 100 kHz 20 12.3 Requirements related to skin temperature rises and times of awareness, perception and withdrawal 21 12.3.1 Skin heat capacity considerations 21 12.3.2 Skin temperature considerations 21 12.4 Risk level categorisation as function of the prospective contact voltage 22 12.5 Addi
21、tional protection: residual current protective devices (RCDs) 22 13 Non-sinusoidal touch currents . 22 14 Warning marking and risk group classifications 23 Annex A (informative) Examples of calculations . 24 A.1 General . 24 A.2 Skin heating 24 A.3 Examples of tissue heating conditions . 29 A.3.1 Wi
22、th 1 500 mm 2fingerskin area, i.e. gripping 29 A.3.2 With the maximal fingerskin area 230 mm 229 Annex B (informative) Rationales, references and volunteer studies in the non-thermal case 31 B.1 Background and observations . 31 B.2 Discussion of Figure B.1 . 31 B.3 A volunteer study at 11 kHz sinuso
23、idal conditions . 33 B.3.1 Experimental setup and data . 33 B.3.2 Discussion and analysis of the experimental data 33 B.4 Contact/touch current data from standards and other published documents 34 B.5 Reference levels for the external electric field . 35 B.6 Prospective touch voltage limits 35 B.7 P
24、erception and pain in relation to risk levels . 35 B.8 Remarks on the slope of the curves for frequencies higher than 10 kHz 36 B.9 Remarks on the touch current levels above 100 kHz in ICNIRP and IEEE specifications 36 Annex C (informative) Additional information and rationales skin data and impedan
25、ces of parts of the body . 37 C.1 Skin anatomy 37 C.2 Comparative calculation procedure for wet skin impedances . 38 C.3 Some data for dry skin 38 C.4 Frequency dependence of the body tissue electrical conductivities . 39 C.5 Calculations for Table 1 39 Bibliography 41 Figure 1 Complex impedances of
26、 various parts of the body, 1 kHz to 6 MHz 15 Figure 2 Maximum allowed touch and touch currents, 1 kHz to 100 kHz, immediate nerve and muscle electric shock . 18 Figure 3 Warning markings 23 Figure B.1 Maximum allowed touch and touch currents in various standards, 1 kHz to 100 kHz, immediate nerve a
27、nd muscle electric shock 32 Figure B.2 Setup for touch current and voltage measurements with index and middle fingers on 50 mm 2flat conductors 33 Figure B.3 Current measuring circuit for unweighed touch current, from IEC 60990:2016 35 Figure C.1 Human skin anatomy (from Wikipedia) 37 4 IEC TS 62996
28、:2017 IEC 2017 Figure C.2 Average electrical conductivities for homogeneous body modelling from 10 Hz to 10 MHz (from EN 50444:2008) 39 Table 1 Maximally allowed skin power density per surface area, under various conditions of withdrawal 22 Table A.1 Comparison of impedances of parts of the body, us
29、ing the equivalent circuits in IEC 60990:2016 and in this document . 25 Table A.2 Moist skin, finger and overall heating rate at 50 V overall effective voltage, using equivalent circuits in IEC 60990:2016 and this document 25 Table A.3 Wet skin, finger and overall heating rate at 50 V overall effect
30、ive voltage, using this document, with halved skin impedances compared with Table A.2 26 Table A.4 Effective contact voltage limits for the moist skin examples in Table A.2 27 Table A.5 Effective contact voltage limits for the wet skin examples in Table A.3 . 28 Table C.1 Comparison of complex imped
31、ances of moist and wet fingers 39 IEC TS 62996:2017 IEC 2017 5 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ INDUSTRIAL ELECTROHEATING AND ELECTROMAGNETIC PROCESSING EQUIPMENT REQUIREMENTS ON TOUCH CURRENTS, VOLTAGES AND ELECTRIC FIELDS FROM 1 kHz TO 6 MHz FOREWORD 1) The International Electrotechnica
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44、ational Standard. Technical specifications are subject to review within three years of publication to decide whether they can be transformed into International Standards. IEC TS 62996, which is a technical specification, has been prepared by IEC technical committee 27: Industrial electroheating and
45、electromagnetic processing. 6 IEC TS 62996:2017 IEC 2017 The text of this document is based on the following documents: Draft TS Report on voting 27/1005/DTS 27/1010/RVDTS Full information on the voting for the approval of this document can be found in the report on voting indicated in the above tab
46、le. This document has been drafted in accordance with the ISO/IEC Directives, Part 2. In this document, the following print types are used: terms defined in Clause 3: in bold type. in Table A.4 and Table A.5, the resulting voltage limits are bolded, for clarity. The committee has decided that the co
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49、d therefore print this document using a colour printer. IEC TS 62996:2017 IEC 2017 7 INTRODUCTION Touch and touch currents and voltages constitute a very important category of electrical safety issues particularly for electroheating (EH) equipment and equipment for electro- magnetic processing of materials (EPM). The equipment manufacturer is mandated to adequately reduce any hazard from touching live equipment parts. For being able to do so, assessments and verificat
