External exposure of roofs to fire

ISO 12468-1:2013 specifies a test method to determine the resistance of roofs to external exposure to fire. This method evaluates the behaviour of the roof when exposed to three types of burning brands combined with wind and with or without heat radiation, concerning the fire spread across the external surface of the roof, the fire spread within the roof, the fire penetration, and the production of flaming droplets or debris falling through the roof, from the underside of the roof, or from the exposed surface.

Exposition des toitures à un feu extérieur

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Status
Published
Publication Date
15-Oct-2013
Current Stage
6060 - International Standard published
Start Date
10-Oct-2013
Completion Date
16-Oct-2013
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INTERNATIONAL ISO
STANDARD 12468-1
Second edition
2013-11-01
External exposure of roofs to fire —
Part 1:
Test method
Exposition des toitures à un feu extérieur —
Partie 1: Méthode d’essais
Reference number
ISO 12468-1:2013(E)
ISO 2013
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ISO 12468-1:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

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Published in Switzerland
ii © ISO 2013 – All rights reserved
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ISO 12468-1:2013(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 3

5 Selection of test specimen pitch ........................................................................................................................................................... 3

6 Test specimens........................................................................................................................................................................................................ 3

6.1 General requirements ....................................................................................................................................................................... 3

6.2 Selection of standard supporting elements ................................................................................................................... 5

6.3 Positioning of joints ............................................................................................................................................................................ 6

6.4 Edge detailing .......................................................................................................................................................................................... 7

7 Test equipment....................................................................................................................................................................................................... 7

7.1 Exposure levels ....................................................................................................................................................................................... 7

7.2 Brands ............................................................................................................................................................................................................. 8

7.3 Wind ..............................................................................................................................................................................................................10

7.4 Radiation ...................................................................................................................................................................................................11

7.5 Timing device ........................................................................................................................................................................................11

7.6 Calibration element..........................................................................................................................................................................11

7.7 Specimen holder .................................................................................................................................................................................11

7.8 Gas burner ......... .......................................................................................................................................................................................15

7.9 Stand .............................................................................................................................................................................................................17

8 Test conditions ....................................................................................................................................................................................................17

8.1 Test environment ...............................................................................................................................................................................17

8.2 Calibration procedure ....................................................................................................................................................................18

9 Conditioning and test preparation .................................................................................................................................................18

9.1 Conditioning ...........................................................................................................................................................................................18

9.2 Protection of the edges .................................................................................................................................................................19

10 Test procedure .....................................................................................................................................................................................................19

10.1 General ........................................................................................................................................................................................................19

10.2 Commencement of the test ........................................................................................................................................................19

10.3 Ignition and positioning of the brands ............................................................................................................................20

10.4 End of the test .......................................................................................................................................................................................21

10.5 Post-test examination ....................................................................................................................................................................21

11 Observations and measurements ....................................................................................................................................................21

11.1 General ........................................................................................................................................................................................................21

11.2 External fire spread .........................................................................................................................................................................21

11.3 Fire penetration ..................................................................................................................................................................................21

11.4 Opening ......................................................................................................................................................................................................21

11.5 Damage .......................................................................................................................................................................................................22

12 Expression of test results..........................................................................................................................................................................22

13 Test report ................................................................................................................................................................................................................22

Annex A (normative) Direct field of application ...................................................................................................................................24

© ISO 2013 – All rights reserved iii
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ISO 12468-1:2013(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT) see the following URL: Foreword - Supplementary information

The committee responsible for this document is ISO/TC 92, Fire Safety, Subcommittee SC 2, Fire Containment.

This second edition cancels and replaces the first edition (ISO 12468–1:2003), of which it constitutes a

minor revision.

ISO 12468 consists of the following parts, under the general title External exposure of roofs to fire:

— Part 1: Test method
— Part 2: Classification of roofs
— Part 3: Commentary
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ISO 12468-1:2013(E)
Introduction

This part of ISO 12468 specifies a test method that relates to the effects of fires on roofs. The test method

described in this part of ISO 12468 represents the effect of three levels of fire exposure.

— Level A: A large burning brand coming from an adjacent building and falling onto the roof. Level A

considers the effects of wind and additional radiant heat.

— Level B: A medium burning brand coming from a fire in a neighbourhood and falling onto the roof.

Level B considers the effect of wind but without additional radiant heat.

— Level C: A small burning brand transported by the wind from a remote fire and falling onto the roof.

Level C considers the effect of wind but without additional radiant heat.
© ISO 2013 – All rights reserved v
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INTERNATIONAL STANDARD ISO 12468-1:2013(E)
External exposure of roofs to fire —
Part 1:
Test method
1 Scope

CAUTION — The attention of all persons concerned with managing and carrying out this fire test

is drawn to the fact that fire testing may be hazardous and that there is a possibility that toxic

and/or harmful smoke and gases may be evolved during the test. Mechanical and operational

hazards may also arise during the construction of the test elements or structures, their testing,

and disposal of test residues. An assessment of all potential hazards and risks to health shall be

made and safety precautions shall be identified and provided. Written safety instructions shall

be issued. Appropriate training shall be given to relevant personnel. Laboratory personnel shall

ensure that they follow written safety instructions at all times.

This part of ISO 12468 specifies a test method to determine the resistance of roofs to external exposure

to fire. This method evaluates the behaviour of the roof when exposed to three types of burning brands

combined with wind and with or without heat radiation, concerning
a) the fire spread across the external surface of the roof,
b) the fire spread within the roof,
c) the fire penetration, and

d) the production of flaming droplets or debris falling through the roof, from the underside of the roof,

or from the exposed surface.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 13943, Fire safety — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13943 and the following apply.

3.1
assembly
fabrication of materials and/or composites
EXAMPLE Sandwich panels.
3.2
burned material
material that has been destroyed by combustion or pyrolysis
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ISO 12468-1:2013(E)
3.3
composite

combination of materials which are generally recognized in building construction as discrete entities

EXAMPLE Coated or laminated product such as roofing felt.
3.4
continuous deck

deck supporting the roof covering in which the gap between adjacent elements is not greater than

0,5 mm (5,0 mm in the case of wooden planks with plain edges)
3.5
damaged material

material that has been burned, melted, or otherwise visually changed by heat but does not include

discoloration and soot deposits
3.6
exposed surface

external surface of the calibration element or of the specimen which is subject to the heat conditions

3.7
external fire spread

progression and extent of sustained flaming across the exposed surface of the specimen

3.8
fire penetration

any opening, sustained flaming, or glowing due to combustion on the underside that appears during the test

and/or the occurrence of any flaming droplets or debris falling through the specimen or from the underside

Note 1 to entry: Charring or discoloration is not to be regarded as fire penetration.

3.9
fire spread within the roof
extent of burned material in each functional layer inside the specimen
3.10
flaming droplets or debris

burning material falling from or through the specimen that continues to burn on the floor for at least 5 s

3.11
internal damage
extent of damaged material in each functional layer inside the specimen
3.12
material
basic single substance or a uniformly dispersed mixture of substances
EXAMPLE Metal, stone, wood, bitumen, concrete, or mineral wool.
3.13
measuring zone
area of the specimen within which measurements are made
3.14
opening

any hole greater than 10 mm × 10 mm that appears during the test which penetrates completely

through the specimen
3.15
product

material (3.12), composite (3.3), or assembly (3.1) about which information is required

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ISO 12468-1:2013(E)
3.16
profile pitch

repeating length between sections of a uniformly corrugated or undulating roof deck

3.17
roof system

covering and sealing systems including any insulating layers or vapour barriers with their supporting

elements and roof lights or other closures for roof apertures that are intended to provide a

weatherproof surface

Note 1 to entry: Elements with a slope greater than 70° are not considered as roofs in this part of ISO 12468.

3.18
roof covering
material (3.12) attached to the deck
3.19
specimen
representative section of the roof system prepared for the purpose of test
3.20
sustained flaming
flaming arising from an observed location, which persists for 5 s or longer
3.21
underside
bottom surface of the specimen
4 Symbols
Symbol Description Unit

v , v , v , v , v , v v Velocity of the air at the measuring points metres per second (m/s)

1 2 3 4 5 6, 7
α Pitch (slope) degrees (°)
5 Selection of test specimen pitch

Roof systems designed for only one pitch shall be tested at the actual design pitch.

Roof systems designed for more than one pitch shall be tested as follows:
a) for pitch (α) less than 5°, test at zero pitch;
b) for pitch (α) from 5° to 20°, test at 15°;
c) for pitch (α) greater than 20°, test at 30°.
6 Test specimens
6.1 General requirements

For each level of fire exposure, two specimens shall be tested with dimensions measuring

1 200 mm ± 10 mm in width × 2 000 mm ± 10 mm in length for each test pitch. (See Figures 1 and 2.)

When this is not possible due to the size of the roof light or other closure, a larger specimen shall be used.

NOTE Roof lights cause difficulties due to their size, shape, composition, and fire behaviour. Further guidance

on the testing of roof lights will be presented in the next revision of this part of ISO 12468.

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ISO 12468-1:2013(E)
The specimens shall be representative in all details of the roof in practice.
Dimensions in millimetres with tolerances of ±10 mm
Key
1 radiant panel position
2 A brands
3 measuring zone
Figure 1 — Measuring zone and position of brands for Level A
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ISO 12468-1:2013(E)
Key
1 measuring zone
2 B brands or C brands
Figure 2 — Measuring zone and position of the brands for Level B or Level C
6.2 Selection of standard supporting elements
6.2.1 For continuous decks
6.2.1.1 General
The test deck shall be selected in accordance with the following:

a) In the case of roof coverings intended to be installed over a continuous deck other than a profiled

metal deck, a roof deck in accordance with 6.2.1.2 or 6.2.1.4 shall be used;
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ISO 12468-1:2013(E)

b) If the materials will only be laid over a profiled metal deck, then a trapezoidal profiled metal deck,

in accordance with 6.2.1.3, shall be used as the deck.
6.2.1.2 Wood particleboard decks

6.2.1.2.1 The wood particleboard shall consist of wood particles bonded with polymer adhesive (e.g.

3 3

urea formaldehyde). This particleboard shall have a density of 680 kg/m ± 50 kg/m and shall not be

treated with fire retardants.

6.2.1.2.2 A wood particleboard deck shall be constructed from planks 250 mm wide × 13 mm ± 1 mm

thick running parallel to the eaves with plain edges and tightly butt jointed so that the gaps between

planks do not exceed 0,5 mm.

6.2.1.2.3 If it is intended also to cover the case of decks made from wooden planks with plain edges,

then these gaps shall be 5 mm ± 0,5 mm.
6.2.1.3 Metal decks

The trapezoidal profiled metal deck shall be made of aluminium or steel (subject to the expected field of

application) and have the width of the crown approximately equal to 50 % of the profile pitch and a trough

depth of approximately 100 mm. The corrugations shall run parallel to the eaves and be open at the ends.

6.2.1.4 Other non-combustible decks

If roofing materials are intended to be laid only on continuous, non-combustible decks with a minimum

thickness of 10 mm, then the test roof deck shall consist of 12 mm ± 2 mm thick reinforced calcium

3 3
silicate board (oven dry density 900 kg/m ± 100 kg/m ).
6.2.2 For non-continuous decks

The spacing of roof supports of any type shall be in accordance with the maximum permissible spans

proposed by the manufacturer for the particular application but not exceeding the minimum dimensions

specified for the specimen in 6.1.
6.3 Positioning of joints
6.3.1 General

The joints shall be representative of practical application. In the case of overlapping layers, the position

of the joints shall be considered to be the edge of the upper layer.
6.3.2 Description of specimen types with respect to joints

Where the dimensions of the elements of any of the layers are such that it requires more than four pieces

to cover the specimen, or if any of the layers are without joints, then the specimens shall be fabricated

such that those layers are representative of actual field practice (see Figures 3 and 4).

Specimens are categorized by the following types:

— Type 1: Single central vertical joint in the top layer. Single horizontal joint in the top layer under

position of the left brand. Single vertical joint in layer next to top layer under position of the right

brand. Single vertical joint in insulation under position of the left brand [see Figure 4 a), Type 1];

— Type 2: Single vertical joint in the top layer under position of the right brand. Single vertical joint in

layer next to insulation under position of the left brand [see Figure 4 b), Type 2];

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ISO 12468-1:2013(E)

— Type 3: One cross joint of the top layer under position of the right brand and, where possible

according to the design of the product, a vertical joint in layer under top under the left brand [see

Figure 4 c), Type 3];

— Type 4: Centre of one element of the top layer and, where possible according to the design of the

product, a vertical joint of supporting deck, under position of the right brand and in insulation under

the left brand [see Figure 4 d), Type 4].
6.3.3 Selection of the specimen types

Either specimen types, Types 1 and 2 or Types 3 and 4, shall be used for each test pitch and for each level

of fire exposure.
6.4 Edge detailing

No special measures shall be taken by the sponsor to protect the edges of the specimen.

Key
1 vertical joint in top layer 6 vertical joint in supporting deck
2 horizontal joint in top layer 7 weathering layer
3 joint in layer next to insulation 8 insulation
4 joint in layer next to top layer 9 roof deck
5 joint in insulation
Figure 3 — Identification of joints in a multilayer roof
7 Test equipment
7.1 Exposure levels
Three levels are defined:
a) Level A consists of Brand A combined with wind and additional radiant heat;

b) Level B consists of Brand B combined with wind and without any additional radiant heat;

c) Level C consists of Brand C combined with wind and without any additional radiant heat.

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ISO 12468-1:2013(E)

The wind is identical for the Levels A, B, and C. The measuring zone, position of the brands, and position

of the radiant panel are shown in Figures 1 and 2.
a) Type 1 b) Type 2
c) Type 3 d) Type 4
Key
1 vertical joint in top layer 4 joint in layer next to top layer
2 horizontal joint in top layer 5 joint in insulation
3 joint in layer next to insulation 6 vertical joint in supporting deck
Figure 4 — Position of joints and types of specimens
7.2 Brands
7.2.1 General

Two brands are utilized for each specimen. The test brands shall be constructed from Beech (Fagus

3 3

salvatica or Fagus grandifolia) having an oven-dry density of 560 kg/m ± 50 kg/m .

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ISO 12468-1:2013(E)

The mass of the finished brand following conditioning in an oven at 40 °C to 50 °C for at least 24 h shall

be 33 g ± 5 g at the time of the test for Brand C, 155 g ± 10 g (less fasteners) at the time of the test for

Brand B, and 550 g ± 50 g (less fasteners) at the time of the test for Brand A.
7.2.2 Brand A

Brand A shall consist of a grid of approximately 150 mm square and 57 mm deep, using nominally

19 mm × 19 mm × 150 mm strips of lumber, placed in three layers of six strips each, placed at right angles

to adjacent layers and spaced equidistant from each other within the brand envelope. The strips shall be

fastened to this configuration using light nails or staples (see Figure 5).
Dimensions in millimetres with tolerances of ±2 mm
Figure 5 — Brand A
7.2.3 Brand B

Brand B shall consist of a grid of approximately 80 mm square and 57 mm deep, using nominally

19 mm × 19 mm × 80 mm strips of lumber, placed in three layers of three strips each, placed at right

angles to adjacent layers and spaced equidistant from each other within the brand envelope. The strips

shall be fastened to this configuration using light nails or staples (see Figure 6).

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ISO 12468-1:2013(E)
Dimensions in millimetres with tolerances of ±2 mm
Figure 6 — Brand B
7.2.4 Brand C

Brand C shall consist of a piece of lumber 40 mm × 40 mm × 40 mm with a saw cut 3 mm wide, half the

thickness of the brand across the centre of the top and bottom faces. The saw cuts on opposite face shall

be at right angles to each other (see Figure 7).
Dimensions in millimetres with tolerances of ±2 mm
Figure 7 — Brand C
7.3 Wind
7.3.1 Apparatus

A wind-generating apparatus capable of applying air across the surface of the calibration element at a

temperature of 20 °C ± 15 °C and a velocity as defined in 8.2.3 shall be used. The apparatus shall have

a control for the volume rate. The wind outlet section of the tube shall have a minimum dimension of

250 mm in height and 1 000 mm in width. The minimum length of the duct shall be 1 200 mm. Baffles

and flow smoothers shall be used to avoid turbulence of the flow pattern.
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ISO 12468-1:2013(E)
7.3.2 Air velocity

A vane anemometer with a diameter no greater than 25 mm shall be used to measure the air velocity.

The instrument shall integrate the average value of the air velocity for a period of 10 s to 30 s at the

respective positions (see Figure 8). The air velocity shall be established parallel to the surface and in the

direction of the longitudinal axis of the calibration element.

So as to minimize the disturbance of the flow pattern in the region of the measuring zone, a supporting

device shall be used.
7.3.3 Eave

A simulated eave shall be installed in front of the test specimen to prevent air from flowing underneath

the test specimen.

This shall be done in a way so as not to interfere with or obstruct material flowing or falling from the

roof surface (see Figures 9 and 10).
7.4 Radiation

A radiant panel of 600 mm ± 10 mm × 600 mm ± 10 mm capable of being mounted in a plane parallel to

the surface of the specimen and at a distance of 500 mm ± 10 mm above it shall be provided.

The radiant panel shall be capable of providing a heat flux distribution on the surface of the specimen as

defined in 8.2.4, with wind. A flux meter having accuracy equal to or better than 5 % of the target value

shall measure the total heat flux.
7.5 Timing device

A timing device with an accuracy better than or equal to 5 s over 1 h shall be provided for the recording

of the sequence of events during each test.
7.6 Calibration element

The calibration element consists of a smooth, flat 12 mm ± 2 mm thick sheet of calcium silicate material

3 3
having the dimension 1 200 mm × 2 000 mm and a density of 900 kg/m ± 100 kg/m .

A 25-mm-diameter Schmit Boelter heat flux meter, with a design range of (0 – 50) kW/m shall be used

to establish the heat flux distribution on the surface of the calibration element. The target receiving

radiation from the radiant panels shall be flat, circular, and coated with a durable matt black finish. The

target shall be water cooled. Radiation shall not pass through any window before reaching the target.

The instrument shall be robust, simple to set up and use, and stable in calibration. The instrument shall

have an accuracy of within ±3 % and a repeatability within 0.5
...

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