Amendment 1 - Fire hazard testing - Part 6-1: Smoke obscuration - General guidance

Applies to capacitors and resistors with unidirectional terminations intended for use in electronic equipment.

Amendement 1 - Essais relatifs aux risques du feu - Partie 6-1: Opacité des fumées - Lignes directrices générales

S'applique aux condensateurs et résistances à sorties unilatérales destinés à être utilisés dans les équipements électroniques. Fournit une méthode pour déterminer l'encombrement.

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Publication Date
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IEC 60695-6-1
Edition 2.0 2010-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
AMENDMENT 1
AMENDEMENT 1
Fire hazard testing –
Part 6-1: Smoke obscuration – General guidance
Essais relatifs aux risques du feu –
Partie 6-1: Opacité des fumées – Lignes directrices générales
IEC 60695-6-1:2005/A1:2010
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
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---------------------- Page: 2 ----------------------
IEC 60695-6-1
Edition 2.0 2010-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
AMENDMENT 1
AMENDEMENT 1
Fire hazard testing –
Part 6-1: Smoke obscuration – General guidance
Essais relatifs aux risques du feu –
Partie 6-1: Opacité des fumées – Lignes directrices générales
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX
ICS 13.220.99; 29.020 ISBN 978-2-88910-939-5
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – 60695-6-1 Amend. 1 © IEC:2010
FOREWORD

This amendment has been prepared by IEC technical committee 89: Fire hazard testing.

The text of this amendment is based on the following documents:
CDV Report on voting
89/905/CDV 89/946A/RVC

Full information on the voting for the approval of this amendment can be found in the report

on voting indicated in the above table.

The committee has decided that the contents of this amendment and the base publication will

remain unchanged until the stability date indicated on the IEC web site under

"http://webstore.iec.ch" in the data related to the specific publication. At this date, the

publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
_____________
2 Normative references
Replace the text of this clause with the following:

The following referenced documents are indispensable for the application 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 60695-1-10, Fire hazard testing – Part 1-10: Guidance for assessing the fire hazard of

electrotechnical products – General guidelines

IEC 60695-1-11 , Fire hazard testing – Part 1-11: Guidance for assessing the fire hazard of

electrotechnical products – Fire hazard assessment

IEC 60695-4:2005, Fire hazard testing – Part 4: Terminology concerning fire tests for

electrotechnical products
, Fire hazard testing – Part 6-2: Smoke obscuration – Summary and relevance
IEC 60695-6-2
of test methods

IEC 60695-6-30:1996, Fire hazard testing – Part 6: Guidance and test methods on the

assessment of obscuration hazard of vision caused by smoke opacity from electrotechnical

products involved in fires – Section 30: Small-scale static method – Determination of smoke

opacity – Description of the apparatus
___________
To be published.
To be published.
---------------------- Page: 4 ----------------------
60695-6-1 Amend. 1 © IEC:2010 – 3 –

IEC 60695-6-31:1999, Fire hazard testing – Part 6-31: Smoke obscuration – Small-scale static

test – Materials

IEC Guide 104:1997, The preparation of safety publications and the use of basic safety

publications and group safety publications
ISO/IEC Guide 51:1999. Safety aspects – Guidelines for inclusion in standards

ISO 5659-2:2006, Plastics – Smoke generation – Part 2: Determination of optical density by a

single-chamber test

ISO 5660-2:2002, Reaction-to-fire tests – Heat release, smoke production and mass loss rate

– Part 2: Smoke production rate (dynamic measurement)
ISO 13943:2008, Fire safety – Vocabulary
ISO 19706:2007, Guidelines for assessing the fire threat to people

NOTE ISO 9122-1:1989, Toxicity testing of fire effluents – Part 1: General, has been withdrawn and replaced by

ISO 19706:2007.

ASTM E 1354:2008, Standard Test Method for Heat and Visible Smoke Release Rates for

Materials and Products Using an Oxygen Consumption Calorimeter

EN 13823:2002, Reaction to fire tests for building products – Building products, excluding

floorings, exposed to thermal attack by a single burning item
3 Terms, definitions and symbols
3.1 Terms and definitions
Replace the text of this subclause with the following:

For the purposes of this document, the terms and definitions given in ISO/IEC 13943, some of

which are reproduced below for the uses’ convenience, as well as the following apply.

3.1.1
combustion
exothermic reaction of a substance with an oxidizing agent

NOTE Combustion generally emits fire effluent accompanied by flames and/or glowing.

[ISO/IEC 13943, definition 4.46]
3.1.2
extinction area of smoke

product of the volume occupied by smoke and the extinction coefficient of the smoke

NOTE It is a measure of the amount of smoke, and the typical units are square metres (m ).

[ISO /IEC 13943, definition 4.92]
3.1.3
extinction coefficient

natural logarithm of the ratio of incident light intensity to transmitted light intensity, per unit

light path length
NOTE Typical units are reciprocal metres (m ).
---------------------- Page: 5 ----------------------
– 4 – 60695-6-1 Amend. 1 © IEC:2010
[ISO/IEC 13943, definition 4.93]
3.1.4
fire

〈general〉 process of combustion characterized by the emission of heat and fire effluent and

usually accompanied by smoke, flame or glowing or a combination thereof

NOTE In the English language the term "fire" is used to designate three concepts, two of which, fire (3.1.5) and

fire (3.1.6), relate to specific types of self-supporting combustion with different meanings and two of them are

designated using two different terms in both French and German.
[ISO/IEC 13943, definition 4.96]
3.1.5
fire

〈controlled〉 self-supporting combustion that has been deliberately arranged to provide useful

effects and is limited in its extent in time and space
[ISO/IEC 13943, definition 4.97]
3.1.6
fire

〈uncontrolled〉 self-supporting combustion that has not been deliberately arranged to provide

useful effects and is not limited in its extent in time and space
[ISO/IEC 13943, definition 4.98]
3.1.7
fire effluent

totality of gases and aerosols, including suspended particles, created by combustion or

pyrolysis in a fire
[ISO/IEC 13943, definition 4.105]
3.1.8
fire hazard

physical object or condition with a potential for an undesirable consequence from fire

[ISO/IEC 13943, definition 4.112]
3.1.9
fire model
fire simulation

calculation method that describes a system or process related to fire development, including

fire dynamics and the effects of fire
[ISO/IEC 13943, definition 4.116]
3.1.10
fire scenario

qualitative description of the course of a fire with respect to time, identifying key events that

characterise the studied fire and differentiate it from other possible fires

NOTE It typically defines the ignition and fire growth processes, the fully developed fire stage, the fire decay

stage, and the environment and systems that impact on the course of the fire.
[ISO/IEC 13943, definition 4.129]
---------------------- Page: 6 ----------------------
60695-6-1 Amend. 1 © IEC:2010 – 5 –
3.1.11
flashover

〈stage of fire〉 transition to a state of total surface involvement in a fire of combustible

materials within an enclosure
[ISO/IEC 13943, definition 4.156]
3.1.12
heat flux

amount of thermal energy emitted, transmitted or received per unit area and per unit time

NOTE The typical units are watts per square metre (W·m ).
[ISO/IEC 13943, definition 4.173]
3.1.13
ignition
sustained ignition (deprecated)
〈general〉 initiation of combustion
[ISO/IEC 13943, definition 4.187]
3.1.14
ignition
sustained ignition (deprecated)
〈flaming combustion〉 initiation of sustained flame
[ISO/IEC 13943, definition 4.188]
3.1.15
large-scale fire test

fire test, that cannot be carried out in a typical laboratory chamber, performed on a test

specimen of large dimensions

NOTE A fire test performed on a test specimen of which the maximum dimension is greater than 3 m is usually

called a large-scale fire test.
[ISO/IEC 13943, definition 4.205]
3.1.16
mass optical density of smoke

optical density of smoke multiplied by a factor, V/(Δm L), where V is the volume of the test

chamber, Δm is the mass lost from the test specimen, and L is the light path length

2 -1
NOTE The typical units are square metres per gram (m ⋅g ).
[ISO/IEC 13943, definition 4.225]
3.1.17
obscuration by smoke
reduction in the intensity of light due to its passage through smoke

cf. extinction area of smoke (3.1.2) and specific extinction area of smoke (3.1.26).

NOTE 1 In practice, obscuration by smoke is usually measured as the transmittance, which is normally expressed

as a percentage.
NOTE 2 Obscuration by smoke causes a reduction in visibility.
[ISO/IEC 13943, definition 4.242]
---------------------- Page: 7 ----------------------
– 6 – 60695-6-1 Amend. 1 © IEC:2010
3.1.18
opacity of smoke

ratio of incident light intensity to transmitted light intensity through smoke, under specified

conditions
cf. obscuration by smoke (3.1.17)
NOTE 1 Opacity of smoke is the reciprocal of transmittance.
NOTE 2 The opacity of smoke is dimensionless.
[ISO/IEC 13943, definition 4.243]
3.1.19
optical density of smoke

measure of the attenuation of a light beam passing through smoke expressed as the logarithm

to the base 10 of the opacity of smoke
cf. specific optical density of smoke (3.1.26)
NOTE The optical density of smoke is dimensionless.
[ISO/IEC 13943, definition 4.244]
3.1.20
real-scale fire test

fire test that simulates a given application, taking into account the real scale, the real way the

item is installed and used, and the environment

NOTE Such a fire test normally assumes that the products are used in accordance with the conditions laid down

by the specifier and/or in accordance with normal practice.
[ISO/IEC 13943, definition 4.273]
3.1.21
small-scale fire test
fire test performed on a test specimen of small dimensions

NOTE A fire test performed on a test specimen of which the maximum dimension is less than 1 m is usually called

a small-scale fire test.
[ISO/IEC 13943, definition 4.292]
3.1.22
SMOGRA

smoke growth rate parameter that is a function of the rate of smoke production and the time of

smoke production
NOTE Further details are given in 6.2.4.
3.1.23
SMOGRA index
maximum value of SMOGRA during a defined test period
NOTE Further details are given in 6.2.4.
3.1.24
smoke
visible part of fire effluent
[ISO/IEC 13943, definition 4.293]
---------------------- Page: 8 ----------------------
60695-6-1 Amend. 1 © IEC:2010 – 7 –
3.1.25
smoke production rate
amount of smoke produced per unit time in a fire or fire test

NOTE 1 It is calculated as the product of the volumetric flow rate of smoke and the extinction coefficient of the

smoke at the point of measurement.
2 -1
NOTE 2 The typical units are square metres per second (m ⋅s ).
[ISO/IEC 13943, definition 4.295]
3.1.26
specific extinction area of smoke

extinction area of smoke produced by a test specimen in a given time period divided by the

mass lost from the test specimen in the same time period
2 -1
NOTE The typical units are square metres per gram (m ·g ).
[ISO/IEC 13943, definition 4.301]
3.1.27
specific optical density of smoke
optical density of smoke multiplied by a geometric factor

NOTE 1 The geometric factor is equal to V /(A⋅L), where V is the volume of the test chamber, A is the area of the

exposed surface of the test specimen, and L is the light path length.

NOTE 2 The use of the term “specific” does not denote “per unit mass” but rather denotes a quantity associated

with a particular test apparatus and area of the exposed surface of the test specimen.

NOTE 3 The specific optical density of smoke is dimensionless.
[ISO/IEC 13943, definition 4.303]
3.1.28
visibility

maximum distance at which an object of defined size, brightness and contrast can be seen

and recognized
[ISO/IEC 13943, definition 4.350]
4 General aspect of smoke test methods
4.1 Fire scenarios and fire models
Replace, in the first paragraph, the text of the third line with the following:

Table 1 shows how the different types of fire relate to the changing atmosphere.

Replace the text of the third paragraph of this subclause with the following:

General guidance for the fire hazard assessment of electrotechnical products is given in

IEC 60695-1-10.
Table 1 – General classification of fires (ISO/TR 9122-1)
Replace the existing title and table with the following:
---------------------- Page: 9 ----------------------
– 8 – 60695-6-1 Amend. 1 © IEC:2010
Table 1 – Characteristics of fire stages (ISO 19706)
Max. temperature Oxygen
Heat flux [CO] 100×[CO2]
Fuel/air
°C volume %
to fuel
Fire stage equivalence
[CO2] ([CO2] + [CO])
surface
ratio (plume)
Fuel surface Upper layer Entrained Exhausted
kW/m
v/v % efficiency
1. Non-flaming
a) self-sustaining not d
450 to 800 25 to 85 20 20 ⎯ 0,1 to 1 50 to 90
(smouldering) applicable
b) oxidative pyrolysis from a b c c
⎯ 300 to 600 20 20 < 1
externally applied radiation
c) anaerobic pyrolysis from b c c
⎯ 100 to 500 0 0
>> 1
externally applied radiation
d e

2. Well-ventilated flaming 0 to 60 350 to 650 50 to 500 ≈ 20 ≈ 20 < 1 < 0,05 > 95

3. Under-ventilated flaming
a) small, localized fire,

generally in a poorly 0 to 30 300 to 600 50 to 500 15 to 20 5 to 10 0,2 to 0,4 70 to 80

> 1
ventilated compartment
g i
b) post-flashover fire 50 to 150 350 to 650 0,1 to 0,4 70 to 90
> 600 < 15 < 5 > 1

The upper limit is lower than for well-ventilated flaming combustion of a given combustible.

The temperature in the upper layer of the fire room is most likely determined by the source of the externally applied radiation and room geometry.

There are few data; but for pyrolysis, this ratio is expected to vary widely depending on the material chemistry and the local ventilation and thermal conditions.

The fire’s oxygen consumption is small compared to that in the room or the inflow, the flame tip is below the hot gas upper layer or the upper layer is not yet

significantly vitiated to increase the CO yield significantly, the flames are not truncated by contact with another object, and the burning rate is controlled by the

availability of fuel.

The ratio may be up to an order of magnitude higher for materials that are fire-resistant. There is no significant increase in this ratio for equivalence ratios up

to ≈ 0,75. Between ≈ 0,75 and 1, some increase in this ratio may occur.

The fire’s oxygen demand is limited by the ventilation opening(s); the flames extend into the upper layer.

Assumed to be similar to well-ventilated flaming.

The plume equivalence ratio has not been measured; the use of a global equivalence ratio is inappropriate.

Instances of lower ratios have been measured. Generally, these result from secondary combustion outside the room vent.

---------------------- Page: 10 ----------------------
60695-6-1 Amend. 1 © IEC:2010 – 9 –

Figure 1 – Chart of different phases in the development of a fire within a compartment

Replace the Figure 1 and the title with the following:
Stage 3
Stage 2
Developing fire
Stage 1
Decay stage
Well-ventilated Fully developed fire
Non-flaming
flaming
Fire types 1a), Fire type 3b)
Fire type 2
1b) and 1c)
Time
Ignition Flash-over
IEC 1111/10
Figure 1 – Different phases in the development of a fire within a compartment
6 Static and dynamic methods
Replace the text of the existing Clause 6 with the following new text:
6.1 Static methods
6.1.1 Principles

In a static smoke test, the test specimen burns in a closed chamber and the smoke produced

builds up over time. In some tests, a fan stirs the smoke to prevent layering and to make it

homogeneous. The amount of smoke is measured by monitoring the attenuation of a light

beam shining through the smoke.
6.1.2 Extinction area

The extinction area of the smoke is a useful measure of the amount of smoke produced, and

is a function of the opacity of the smoke, ( I / T ), the volume of the chamber, V, and the light

path length, L.
S = (V / L) In (I / T ) (17)

This equation only applies if the smoke is homogeneous. The units of extinction area are

typically square metres (m ).
6.1.3 Specific optical density

In some tests, including IEC 60695-6-30 and ISO 5659-2, the amount of smoke is calculated

from the optical density of the smoke, and it is normalised to the surface area of the test

specimen, A. The quantity calculated is D , the specific optical density.
D =[]V /(AL) log (I /T ) (18)
s 10
Compartment temperature
---------------------- Page: 11 ----------------------
– 10 – 60695-6-1 Amend. 1 © IEC:2010

The thickness of the test specimen will affect the amount of smoke produced. D values

should not be directly compared for test specimens of different thicknesses. Conversely, if

comparisons are made, then the test specimen thickness should be kept constant.
6.1.4 Prediction of visibility

The purpose of measuring D (or S) is to enable the prediction of visibility. However, the

visibility within the test chamber is not usually what is required to be known. What is required

is an estimation of visibility in a given scenario. It is possible to make such estimations based

on data obtained in static tests such as IEC 60695-6-30 but it must be appreciated that such

calculations are only estimates, as changing the fire model will probably change both the

smoke production process and the way in which the smoke will age.
6.2 Dynamic methods
6.2.1 Principles

In dynamic tests, the smoke from the test specimen is drawn through an exhaust system at a

measured flow rate and the opacity of the smoke stream is measured at regular intervals by

monitoring the transmitted intensity of a light beam shining through the smoke (see Figure 4).

The flow rate of the smoke is measured at a position close to where the opacity is measured.

& &
Smoke with extinction
V L V
coefficient = k
IEC 011/01
Figure 4 – Dynamic smoke measurement
6.2.2 Smoke production rate

The smoke production rate at any given moment ( S ) is calculated using the equation:

• •
S = kV (19)
where
V is the volume flow rate of the exhaust gases.
2 –1
S has units of area/time, e.g. m ⋅s .

The smoke production rate is readily ascertained in dynamic systems. It expresses the

extinction area of smoke produced per unit time.
& & &
S = kV = (1 / L ) In (I / T )V (20)

When the exposed test specimen area involved is known, as in the cone calorimeter

ASTM E 1354 and ISO 5660, or furniture calorimeters, the smoke production rate can be

normalized per unit area of the exposed test specimen. The units then become reciprocal time,

2 2 –1
e.g. (m /s)/m , i.e. s .
---------------------- Page: 12 ----------------------
60695-6-1 Amend. 1 © IEC:2010 – 11 –
6.2.3 Total smoke production

Integrated data on total smoke production is also of interest, especially when comparing

materials or scenarios that may produce smoke for unequal periods of time. Total smoke

production is measured as the extinction area produced in the defined time interval and is

given by:
S = S dt (21)
where
S is the total smoke production, i.e. the total extinction area;
t is the time.

The time over which the summation is performed should be specified. In the cone calorimeter,

this is to the end of the test, which, in simple cases, is when the mass loss rate per unit area

–2 –1

of the test specimen has reached a specified value (for example 25 g⋅m ⋅s ). The total

smoke production may be expressed per unit of burning area if this is known.

The total smoke production from a burning test specimen, measured in a closed system, will

often be substantially less than the total smoke production from a similar burning test

measured in a dynamic system. This is because measurements in static systems are more

influenced by losses due to ageing and deposition or interaction at the chamber walls.

6.2.4 SMOGRA index

SMOGRA is an abbreviation for Smoke Growth Rate. SMOGRA values are affected by both

the rate of smoke production and the time at which the smoke is being produced, and are

calculated using the following formula:
SMOGRA = 10 000 × [SPR (t) / (t-t )] (22)
av 0
where
SPR (t) is the smoke production rate at time t, and
t is the time at which the test specimen is first exposed to the test flame.

The SMOGRA index is defined as the maximum value of the function during the time period of

the test.

The SMOGRA index was devised in the development of EN 13823, which is an intermediate

scale corner test used for the regulation of building products in Europe. As a single value

parameter for regulatory purposes, some consider that the SMOGRA index gives a better

indication of the severity of smoke production than either total smoke production or the

average rate of smoke production.

NOTE In EN 13823, the SPR value is a 60 s moving average, and the start of exposure of the test specimen to

the test flame is at t = 300 s.

Figure 5 shows an example SPR versus t curve, and Figure 6 shows the SMOGRA curve

2 –1

derived from these data. The peak smoke production rate is 0,5 m ⋅s at t = 960 s, and the

2 –2
SMOGRA index is 8,2 m ⋅s at t = 857 s.
The SMOGRA index may be a useful parameter for assessing smoke hazard because it

combines the smoke production rate with the time elapsed to reach it. Note that the SMOGRA

index always refers to a time shorter than the time of maximum smoke production (in the

given curves, 857 s compared to 960 s).
---------------------- Page: 13 ----------------------
– 12 – 60695-6-1 Amend. 1 © IEC:2010

However, the SMOGRA index should be treated with extreme caution in cases where there is

an early rapid but low smoke production. In such cases, the SMOGRA value at small t-t

values may be larger than values calculated from the significant part of the curve and the

obtained SMOGRA index may be both irrelevant and misleading.
2 -1
Peak SPR = 0,5 m ⋅ s at t = 960 s
0,6
0,5
0,4
0,3
0,2
0,1
1 200 1 500
0 300 600 900
Time/s
IEC 1112/10
Figure 6 – Example SPR versus t curve
2 -2
SMOGRA index = 8,2 m ⋅ s at t = 857 s
0 300 600 900 1 200 1 500
Time/s
IEC 1113/10
Figure 7 – SMOGRA curve derived from Figure 6
2 -2
SMOGRA/m ⋅ s
2 -1
SPR /m ⋅ s
---------------------- Page: 14 ----------------------
60695-6-1 Amend. 1 © IEC:2010 – 13 –
Annex A – Calculation of visibility

Replace, in the first line of first paragraph, the bibliographical reference [3] by [2].

Replace, in the last line of the second paragraph, the bibliographical reference [4] by [3].

Replace, in the last line of this annex, the bibliographical reference [5] by [4].

Annex C – Relationships between per cent transmission, as measured in a “three metre

cube” enclosure, and extinction area

Replace, in the first line of second paragraph, the bibliographical references [6] and [7] by [5]

and [6] respectively.
Bibliography
Change reference [1] as follows:

[1] Mulholland, G. W., Smoke Production and Properties, in the SFPE Handbook of Fire

Protection Engineering, 3 edn., DiNenno, P. J. et al. (Editors), NFPA, Quincy, MA,

USA, 2002
Delete the reference [2] .
Renumber the subsequent bibliographical references.accordingly.
___________
---------------------- Page: 15 ----------------------
– 14 – 60695-6-1 Amend. 1 © CEI:2010
AVANT-PROPOS

Le présent amendement a été établi par le comité d’études 89 de la CEI: Essais relatifs aux

risques du feu.
Le texte de cet amendement est issu des documents suivants:
CDV Rapport de vote
89/905/CDV 89/946A/RVC

Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant

abouti à l’approbation de cet amendement.

Le comité a décidé que le contenu de cet amendement et de la publication de base ne sera

pas modifié avant la date de stabilité indiquée sur le site web de la CEI sous

"http://webstore.iec.ch" dans les données relatives à la publication recherchée. A cette date,

la publication sera
• reconduite;
• supprimée,
• remplacée par une édition révisée, ou
• amendée.
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2 Références normatives
Remplacer le texte de cet article par ce qui suit:

Les documents de référence suivants sont indispensables pour l'application du présent

document. Pour les références datées, seule l’édition citée s’applique. Pour les références

non datées, la dernière édition du document de référence s'applique (y compris les éventuels

amendements).

CEI 60695-1-10, Essais relatifs aux risques du feu – Partie 1-10: Lignes directrices pour

l’évaluation des risques du feu des produits électrotechniques – Lignes directrices générales

CEI 60695-1-11 , Essais relatifs aux risques du feu – Partie 1-11: Lignes directrices pour

l’évaluation des risques du feu des produits électrotechniques – Evaluation des risque

...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.