IEC TS 60079-39:2015

IEC TS 60079-39 ®
Edition 1.0 2015-06
TECHNICAL
SPECIFICATION
colour
inside
Explosive atmospheres –
Part 39: Intrinsically safe systems with electronically controlled spark duration
limitation
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IEC TS 60079-39 ®
Edition 1.0 2015-06
TECHNICAL
SPECIFICATION
colour
inside
Explosive atmospheres –
Part 39: Intrinsically safe systems with electronically controlled spark duration

limitation
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-2734-3

– 2 – IEC TS 60079-39:2015 © IEC 2015
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references. 8
3 Definitions . 9
4 Power-i architecture . 10
5 Requirements for Power-i devices . 11
5.1 General . 11
5.2 Power-i source . 11
5.3 Power-i field device . 13
5.4 Power-i wiring . 14
5.5 Power-i terminator . 15
5.6 Test instruments for Power-i loop check . 15
5.7 Power-i application classes . 15
6 System requirements . 16
6.1 Selection of the permissible Power- i current class of the Power-i source . 16
6.2 Verification of a Power-i system . 17
7 Assessment and testing . 19
7.1 Procedure to define safety-relevant parameters . 19
7.2 Type test . 20
7.3 Routine test . 20
8 Marking of Power-i devices . 20
8.1 General . 20
8.2 Examples of marking . 20
9 Instructions. 21
Annex A (normative) Assessment of Power-i safety parameters . 22
A.1 General . 22
A.2 Power-i specific test equipment . 22
A.2.1 Power-i universal test equipment . 22
A.2.2 Power-i dummy load . 23
A.3 Determination of the safety-relevant parameters for Power-i devices and
Power-i wiring . 24
A.3.1 General . 24
A.3.2 Safety-relevant parameters for the Power-i source . 24
A.3.3 Safety-relevant parameters for the Power-i field devices . 31
A.3.4 Safety-relevant parameters for Power-i wiring . 34
A.3.5 Safety-relevant parameters for the Power-i terminator . 36
Annex B (informative) Explanation and details of the Power-i basic concept . 37
B.1 Physical basics of an ignition . 37
B.2 Output characteristics of a Power-i source . 39
B.3 Measurement and scientific results as basis for Power- i minimum ignition
values . 41
B.3.1 Test setups for the determination of the ignition probability . 41
B.3.2 Result of the spark ignition tests and their implementation in Table 3 . 43

Annex C (informative) Examples of Power-i devices and systems . 46
C.1 Power-i application for a solenoid valve . 46
C.2 Example of a generally designed Power-i source . 47
C.3 Example of a Power-i field device . 47
C.4 Example of a Power-i dummy load . 48
C.5 Example of a Power-i terminator . 48
Annex D (informative) Example of interconnection of Power-i devices including
Power-i wiring to a Power-i system . 50
D.1 Specific aim and given values . 50
D.2 Solution example . 50

Figure 1 – The simplest Power-i architecture . 10
Figure 2 – Example of complex Power-i concept architecture . 11
Figure 3 – Elements of a Power-i source with voltage and current limitation . 12
Figure 4 – Example of a universal Power-i field device (basic structure) . 14
Figure 5 – Basic assessment procedure for a Power-i system . 19
Figure A.1 – Basic principle of the Power-i universal test equipment . 23
Figure A.2 – Pulse output between terminals 3 and 1 of Figure A.1 . 23
Figure A.3 – Basic principle of a Power-i dummy load . 24
Figure A.4 – Basic principle of the equipment for the determination of the response
time t . 25
resp-source
Figure A.5 – Example of an oscillogram to determine the response time t . 26
resp-source
Figure A.6 – Test equipment for the determination of the assessment factor AF
source
(basic principle) . 27
Figure A.7 – Test equipment for the assessment factor test for Power-i source . 28
Figure A.8 – Example of an oscillogram from a test of a Power-i source with an
assessment factor AF = 8,29 for a break spark . 29
Figure A.9 – Test equipment for transition pulse test of a Power-i source . 30
Figure A.10 – Test equipment for the determination of the assessment factor
AF for Power-i field devices (basic principle) . 32
field device
Figure A.11 – Test equipment for the transition pulse test of Power-i field devices . 33
Figure A.12 – Evaluation parameter of test pulse U for transition pulse test . 34
pulse
Figure A.13 – Test equipment for the determination of the response time of the Power-
i trunk t (basic principle) . 35
resp-trunk
Figure B.1 – Example of a typical trace of a break spark supplied with a linearly limited
source . 38
Figure B.2 – Example of a typical trace of a break spark limited by a Power-i source . 38
Figure B.3 – Example of output set of characteristic curves of a Power-i source during
load connection . 40
Figure B.4 – Basic principle of a Power-i power source for the voltage threshold return
mode . 41
Figure B.5 – Example of output set of characteristic curves of a Power-i source in the
case of a failure . 41
Figure B.6 – Test setup with STA for break sparks . 42
Figure B.7 – Test setup with STA for make sparks . 42
Figure B.8 – Power-i ignition values for voltage class 24V (24 VDC) . 43
Figure B.9 – Power-i ignition values for voltage class 32V (32 VDC) . 44

– 4 – IEC TS 60079-39:2015 © IEC 2015
Figure B.10 – Power-i ignition values for voltage class 40V (40 VDC) . 44
Figure B.11 – Ignition energy in relation to the used hydrogen percentage in the gas
mixtures . 45
Figure C.1 – Simple solenoid valve Power-i application (example) . 46
Figure C.2 – Example of a generally styled Power-i field device . 47
Figure C.3 – Example of a V-limitation unit (level of protection “ib”) . 48
Figure C.4 – Example of a Power-i dummy load . 48
Figure C.5 – Example of a Power-i terminator .
...