IEC 60695-6-1:2021

IEC 60695-6-1 ®
Edition 3.0 2021-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
HORIZONTAL PUBLICATION
Fire hazard testing –
Part 6-1: Smoke obscuration – General guidance

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IEC 60695-6-1 ®
Edition 3.0 2021-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
HORIZONTAL PUBLICATION
Fire hazard testing –
Part 6-1: Smoke obscuration – General guidance
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.220.99; 29.020 ISBN 978-2-8322-4443-2

– 2 – IEC 60695-6-1:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
1 Scope . 8
2 Normative references. 8
3 Terms, definitions and symbols . 9
3.1 Terms and definitions . 9
3.2 Symbols . 9
4 General aspects of smoke test methods . 14
4.1 Fire scenarios and physical fire models . 14
4.2 Factors affecting smoke production . 15
4.2.1 General . 15
4.2.2 Modes of decomposition . 16
4.2.3 Ventilation and the burning environment . 19
4.2.4 Time and temperature . 19
4.2.5 Removal mechanisms for smoke particles. 19
5 Principles of smoke measurement . 19
5.1 General . 19
5.2 Bouguer's law . 19
5.3 Extinction area . 20
5.4 Log units . 21
5.5 Light sources . 21
5.6 Specific extinction area of smoke. 21
5.7 Mass optical density of smoke . 22
5.8 Visibility . 23
6 Static and dynamic methods . 23
6.1 Static methods . 23
6.1.1 Principles . 23
6.1.2 Extinction area of smoke . 23
6.1.3 Specific optical density of smoke . 24
6.1.4 Prediction of visibility . 24
6.2 Dynamic methods . 24
6.2.1 Principles . 24
6.2.2 Smoke production rate . 24
6.2.3 Total smoke production . 25
6.2.4 SMOGRA index . 25
7 Test methods . 26
7.1 Consideration of test methods . 26
7.2 Selection of test specimen . 27
8 Presentation of data . 27
9 Relevance of data to hazard assessment . 27
Annex A (informative) Calculation of visibility . 30
A.1 General . 30
A.2 Example. 30
Annex B (informative) Relationships between D and some other smoke parameters
s
as measured in IEC 60695-6-30 and IEC 60695-6-31 ISO 5659-2 [4] . 32

Annex C (informative) Relationships between per cent transmission, as measured in a
"three metre cube" enclosure, and extinction area . 34
Bibliography . 36

Figure 1 – Different phases in the development of a fire within a compartment . 15
Figure 2 – Attenuation of light by smoke . 20
Figure 3 – Extinction area . 21
Figure 4 – Dynamic smoke measurement . 24
Figure 5 – Example SPRav versus t curve . 26
Figure 6 – SMOGRA curve derived from Figure 5 . 26
Figure 7 – Evaluation and consideration of smoke test methods . 29
Figure A.1 – Visibility (ω) versus extinction coefficient (k) . 30
Figure B.1 – Smoke parameters related to D as measured in IEC 60695-6-30 and
s
IEC 60695-6-31 ISO 5659-2 . 33
Figure C.1 – Extinction area (amount of smoke) related to per cent transmission as
measured in the "three metre cube" . 35

Table 1 – Characteristics of fire stages (from Table 1 in ISO 19706:2011) . 17
Table B.1 – Conversion from D to some other smoke parameters as measured in
s
IEC 60695-6-30 and IEC 60695-6-31 ISO 5659-2 . 32
Table C.1 – Conversions from per cent transmission, as measured in the "three metre
cube" to amount of smoke (extinction area) . 34

– 4 – IEC 60695-6-1:2021 RLV © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIRE HAZARD TESTING –
Part 6-1: Smoke obscuration –
General guidance
FOREWORD
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This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 60695-6-1:2005+AMD1:2010 CSV. A vertical bar appears in the margin
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International Standard IEC 60695-6-1 has been prepared by IEC technical committee 89: Fire
hazard testing.
This third edition cancels and replaces the second edition of IEC 60695-6-1 published in
...