oSIST prEN 1366-8:2019

SLOVENSKI STANDARD
01-maj-2019
Preskusi požarne odpornosti servisnih inštalacij - 8. del: Kanali za odvod dima
Fire resistance tests for service installations - Part 8: Smoke extraction ducts
Feuerwiderstandsprüfungen für Installationen - Teil 8: Entrauchungsleitungen
Essais de résistance au feu des installations de service - Partie 8 : Conduits d’extraction
de fumées
Ta slovenski standard je istoveten z: prEN 1366-8
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
91.060.40 Dimniki, jaški, kanali Chimneys, shafts, ducts
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2019
ICS 13.220.20; 13.220.50 Will supersede EN 1366-8:2004
English Version
Fire resistance tests for service installations - Part 8:
Smoke extraction ducts
Essais de résistance au feu des installations de service - Feuerwiderstandsprüfungen für Installationen - Teil 8:
Partie 8 : Conduits d'extraction de fumées Entrauchungsleitungen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 127.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1366-8:2019 E
worldwide for CEN national Members.

Contents Page
European foreword 4
Introduction 5
1 Scope 6
2 Normative references 6
3 Terms and Definitions 7
4 Caution 8
5 Test equipment 8
5.1 General 8
5.2 Furnace 8
5.3 Perforated plate 8
5.4 Inlet nozzles 9
5.5 Ambient temperature leakage measuring device 10
5.6 Pressure sensors for differential pressure control 10
5.7 Welded connecting duct 10
5.8 Extraction fan 10
5.9 Thermocouples 10
5.10 Surface thermocouples 10
5.11 Oxygen measuring equipment 10
5.12 Oxygen measurement probes 10
5.13 Restraining equipment 11
5.14 Deflection measurements 11
6 Test conditions 11
7 Test specimen 11
7.1 Size 11
7.1.1 General 11
7.1.2 Length 11
7.1.3 Cross-section 11
7.2 Number 12
7.3 Design 12
7.3.1 General 12
7.3.2 Openings in duct 12
7.3.3 Joints in horizontal ducts 12
7.3.4 Joints in vertical ducts 12
7.3.5 Support for vertical ducts 13
7.3.6 Compensators 13
7.3.7 Access panels 13
8 Installation of test specimen 13
8.1 General 13
8.2 Standard supporting construction 14
8.3 Restraint of ducts 14
8.3.1 Inside the furnace 14
8.3.2 Outside the furnace 14
9 Conditioning 14
9.1 General 14
9.2 Water-based sealing materials 14
10 Application of instrumentation 14
10.1 Thermocouples 14
10.1.1 Furnace thermocouples (plate thermometers) 14
10.1.2 Unexposed surface thermocouples 15
10.1.3 Gas temperature adjacent to nozzles 15
10.2 Pressure 15
10.2.1 Furnace pressure 15
10.2.2 Differential under-pressure in duct 15
10.3 Oxygen measurements 15
10.4 Deflection measurement for determination of reduction in internal cross section area15
11 Test procedure 17
11.1 General 17
11.2 Pre-test calibration of the perforated plate 17
11.3 Test at ambient temperature 17
11.4 Pre-fire test procedures 18
11.5 Fire test 18
12 Performance criteria 19
12.1 General requirements 19
12.2 Criteria at ambient temperature 20
12.2.1 Ambient leakage 20
12.2.2 Reduction in internal cross-section area under ambient conditions outside the
furnace 20
12.3 Criteria under fire conditions 20
12.3.1 General 20
12.3.2 Leakage (Integrity) 20
12.3.3 Integrity 20
12.3.4 Insulation 20
12.3.5 Smoke-Leakage 20
12.3.6 Reduction in internal cross-section area under fire conditions 20
12.3.7 Mechanical stability 21
13 Test report 21
14 Field of direct application of test results 22
14.1 General 22
14.2 Vertical and horizontal ducts 22
14.3 Sizes of ducts 22
14.4 Supporting construction 22
Annex A (informative) Measurement of volume/mass flow 38
Annex B (informative) Measurement of oxygen content Details on measuring oxygen content
with parametric cell analysers 43
Annex C (informative) The usage of correction factors for the consideration of different
parameters 46
Bibliography 51
European foreword
This document (prEN 1366-8:2019) has been prepared by Technical Committee CEN/TC 127
“Fire safety in buildings”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 1366-8:2004.
This European Standard has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association.
EN 1366 “Fire resistance tests for service installations” consists of the following:
— Part 1: Ventilation ducts;
— Part 2: Fire dampers;
— Part 3: Penetration seals;
— Part 4: Linear joint seals;
— Part 5: Service ducts and shafts;
— Part 6: Raised floors;
— Part 7: Closures for conveyors and trackbound transportation systems;
— Part 8: Smoke extraction ducts;
— Part 9: Single compartment smoke extraction ducts;
— Part 10: Smoke control dampers (in course of preparation);
— Part 11: Protective Systems for Essential Services (in course of preparation);
— Part 12: Non-mechanical fire barrier for ventilation ductwork;
— Part 13: Chimneys.
Introduction
This document has been prepared because a method of test for fire resisting smoke extraction
ducts has become necessary to evaluate the ability of fire resisting ducts already tested to
EN 1366-1 to function adequately as smoke extraction ducts.
Leakage is measured at both ambient and elevated temperatures. During the tests, air/gases are
drawn through the duct at a differential pressure between the inside and outside of the duct.
Leakage is determined at ambient temperature by sealing the openings in the duct located in the
furnace and taking flow measurements through a flow-measuring device located just before the
extraction fan. With respect to determining leakage at elevated temperatures, oxygen measuring
techniques are used.
The method described in this test is complex and requires sophisticated instrumentation. It is
not recommended therefore to try to test multiple assemblies in this test.

1 Scope
This document specifies a test method for determining the fire resistance of smoke extraction
ducts. It is applicable only to smoke extraction ducts that pass through another fire
compartment from the fire compartment to be extracted in case of fire. It represents fire
exposure of a fully developed fire.
This method of test is only applicable to ventilation ducts with the following classification
according to EN 13501-3:
— fire from inside and outside i ↔ o;
— applicable to a pressure difference up to 500 Pa;
NOTE 1 Requires that the duct A test(s) has been preformed with an under-pressure of minimum
500 Pa.
— with integrity (E) and insulation (I) criteria equal to or higher than the intended
classification for the smoke extraction duct.
NOTE 2 According to: EN 13501–4:2009/A1:2009 Multi-compartment smoke extraction duct can only
be classified as EI.
For the purposes of the test described in this document, the duct is referred to as duct C.
This test method has been designed to cover both vertical and horizontal smoke extraction
ducts. A vertical system need not be evaluated to this method provided that:
— both horizontal (ho) and vertical (ve) classification according to EN 13501-3 has been
obtained for the ventilation duct, and
— it has been tested in a horizontal orientation to this method.
If the ventilation duct in practice is only used for vertical applications in smoke extraction
systems, only vertical (ve) classification is bound to be used and tested in a vertical orientation
to this method according to EN 13501-3.
This test method is suitable for ducts constructed from non-combustible materials (Euroclass
A1 and A2).
NOTE 3 Using combustible material could lead to an incorrect calculation of the leakage based on the
oxygen measurement. E.g. galvanisation could lead to some negative effects for the measurements.
It is applicable only to four sided ducts; one, two and three sided ducts are not covered.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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.
EN 1363-1, Fire resistance tests - Part 1: General Requirements
EN 1366-1, Fire resistance tests for service installations - Part 1: Ventilation ducts
EN 1507, Ventilation for buildings - Sheet metal air ducts with rectangular section - Requirements
for strength and leakage
EN 60584-1, Thermocouples - Part 1: EMF specifications and tolerances (IEC 60584 1)
EN ISO 13943, Fire safety - Vocabulary (ISO 13943)

3 Terms and Definitions
For the purposes of this document, the terms and definitions given in EN 1363-1 and
EN ISO 13943 and the following, apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
smoke extraction duct
duct used for the extraction of smoke in case of fire and designed to provide a degree of fire
resistance
3.2
fire-resistant ventilation duct
duct used for the distribution or extraction of air and designed to provide a degree of fire
resistance
3.3
self-supporting duct
duct constructed, e.g., from fire-protective boards, without encasing a steel duct
3.4
suspension devices
components used for suspending and fixing a duct from a floor or supporting a duct from a wall
3.5
supporting construction
wall, partition or floor through which the duct passes in the test
3.7
compensator
device used to prevent damage from the forces generated by expansion
3.8
access panel
cover for an inspection opening within the duct
3.9
fire protected steel duct
steel duct with an external insulation to provide fire resistance
3.10
internal surface area with under-pressure
surface area of the duct from the perforated plate to the end of the duct by the inlet nozzles
including the endplate where the nozzles is positioned and excluding the surface of the
perforated plate
3.11
total internal surface area
full internal area of the duct including both end plates

4 Caution
The attention of all persons concerned with managing and carrying out this fire resistance test is
drawn to the fact that fire testing can be hazardous and that there is a possibility that toxic
and/or harmful smoke and gases might be evolved during the test. Mechanical and operational
hazards might 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.
5 Test equipment
5.1 General
In addition to the test equipment specified in EN 1363-1 the following is required:
5.2 Furnace
This shall be capable of subjecting smoke extraction ducts to the standard heating and pressure
conditions specified in EN 1363-1 and be suitable for testing ducts in the horizontal (see
Figure 1) or vertical (see Figure 2) orientation.
It is required that the construction of furnace shall allow observation of at least 75 % of the test
specimen.
5.3 Perforated plate
The perforated plate controls the flow through the duct so the required differential pressure, see
Table 1, can be achieved. Depending on the end-use conditions, a pressure level from Table 1
shall be selected; these levels correspond to typical values used in smoke extraction design. The
plate shall be positioned (250 ± 50) mm from where the duct passes through the furnace wall or
roof, see Figures 1 and 2.
The plate shall be made from austenitic heat-resisting steel (grade number 1.4835) in
accordance with EN 10095 Heat resisting steels and nickel alloys. The number of holes and
dimensions are given in Tables 2 and 3. The thickness of the plates shall be 2,5 ± 0,5 mm.
NOTE 1 Table 2 gives details of perforated plates for standard rectangular ducts of size 1000 mm x
250 mm. For smaller sizes the number of holes will be reduced proportional to the smaller cross section.
NOTE 2 Table 3 gives details of perforated plates for standard circular ducts of diameter 560 mm. For
smaller sizes the number of holes will be reduced proportional to the cross section (a change to larger
sizes is not permitted; see 7.1.2 and Table 5).
Further details of the plate are shown in Figures 3, 4 and 5.

Table 1 — Differential pressures between inside and outside the duct for smoke
extraction ductwork
Differential pressure for fire
Operating differential pressure
at ambient temperature
Pressure level test and pre-test calibration
Pa
Pa
1 −500 −150
2 −1000 −300
3 −1500 −500
Table 2 — Details of perforated plates for testing rectangular ducts (see Figure 3)
Pressure level
Specification for perforations
1 2 3
Total number of holes 550 407 324
Number of holes – horizontally 50 37 36
Number of holes – vertically 11 11 9
Diameter of hole (mm) 10 10 10
Horizontal distance from rim e (mm) 15 15 20
Vertical distance from rim c (mm) 15 15 20
Mounting hole separation a (mm) 19,8 26,9 27,4
Mounting hole separation b (mm) 21,8 22 26,3
Table 3 — Details of perforated plate for testing circular ducts (see Figure 4)
Pressure level
Specification for perforations
1 2 3
Total number of holes 541 403 319
Diameter of hole (mm) 10 10 10
Distance from rim e (mm) 30 35 35
Mounting hole separation a (mm) 20,8 22,2 27,5
Mounting hole separation b (mm) 20,8 22,2 27,5
5.4 Inlet nozzles
The measuring device shall be capable of measuring to an accuracy of + 5 % when used in cold
conditions and shall be suitably mounted to the end of the duct with its piezometric ring
connected to appropriate differential pressure measuring equipment
NOTE 1 For the standard size standard sizes of ducts specified in 7.1, an internal dimension of
diameter = 160 mm of each nozzle is suitable (cf. Figure 7). Descriptions of similar nozzles are given in
EN ISO 5167-3, EN ISO 5167-4 and ISO 5221.
NOTE 2 Suggestion to an inlet nozzles system for standard size ducts is shown on Figure 6 and 7. The
calculation procedure is given in Annex A.

5.5 Ambient temperature leakage measuring device
The measuring device shall be capable of measuring to an accuracy of + 5 % and suitably
mounted at the end of the duct, connected to appropriate differential pressure measuring
equipment. Descriptions of possible measuring device are given in EN ISO 5167 series and
ISO 5221.
5.6 Pressure sensors for differential pressure control
A tube sensor as specified in EN 1363-1 shall be located at the end of the duct, inside the duct, at
the level of its centre line. A second sensor (e.g. an open end of a measuring tube) shall be
located on the same level outside the duct. This is shown on Figure 6 and 7 as probe D1.
5.7 Welded connecting duct
A duct tightly welded, which is designed to provide a suitable gas tight connection between the
inlet nozzles and the oxygen measuring probes, shall be provided.
One end of the duct is designed to connect between the test specimen and the extraction fan. An
inlet opening may be provided if a flow control damper is used for fine control of the differential
pressure (see 5.6). This is shown on Figure 7, item 7.
5.8 Extraction fan
A fan for extracting gas under the fire test with a suggested capacity of at least 2 x Vn where Vn
is the required capacity calculated by multiplying the air speed (2 m/s) by the height and width
of the duct, e.g. for the rectangular duct described in 7.1.2 with cross section of 1 m x 0,25 m:
Vn = 2 m/s x 1,0 m x 0,25 m = 0,5 m /s
The characteristic curves of the fan shall be horizontal for the actual air flow. The capacity of the
fan shall not change by more than 10 % in the event of a drop in the pressure of up to 50 Pa.
5.9 Thermocouples
Sheathed thermocouples shall be provided for measuring the gas temperature adjacent to the
nozzles of nickel chromium/nickel aluminium type K wire as defined in EN 60584-1, with a
nominal diameter of 1,5 mm to 3 mm. The thermocouples shall measure with an accuracy
of ± 15 K. The position is shown on Figure 6 and 7, item 6.
5.10 Surface thermocouples
Surface thermocouples for measuring surface temperature of the type specified in EN 1363-1
and at the locations specified in EN 1366-1 shall be used.
5.11 Oxygen measuring equipment
Equipment for measuring the oxygen content of gases shall be provided. This system shall
consist of paramagnetic cell oxygen analysers together with appropriate equipment for cooling,
filtering and drying the gases. Appropriate connecting tubes and probes shall be provided. The
90 % response time of the complete system shall be 20 s maximum. The accuracy shall be equal
to or better than + 0,1 %.
5.12 Oxygen measurement probes
Steel probes shall be provided for extracting the furnace gas from the inside of the duct at the
locations G1 and G2 on Figure 6. The end of the probe shall be located in the centre point of the
duct cross section.
5.13 Restraining equipment
Restraining equipment shall be applied as for duct B in EN 1366-1.
5.14 Deflection measurements
Deflection measurements shall be taken for determining the reduction of internal cross-section
area at ambient temperature and during the fire test. The measurement shall be done with an
accuracy of ± 1mm.
The interval between a complete set of measurements shall not exceed 15 min, in any case near
prior to any classification time period.
6 Test conditions
The heating conditions and the furnace atmosphere shall conform to those given in EN 1363-1.
The furnace pressure shall be controlled to Δ P = 15 Pa throughout the test at the mid-height
position of the horizontal ducts. For vertical ducts the furnace pressure shall be controlled to
ΔP = 20 Pa at a distance of 100 mm below the ceiling. The tolerance of the pressure differential
is given in EN 1363-1.
Details of test conditions within the ducts during the test are given in Clause 11.
7 Test specimen
7.1 Size
7.1.1 General
For duct specimens of sizes other than those given in Table 5, the field of direct application is
restricted (see Clause 14).
7.1.2 Length
The minimum lengths of the parts of the test specimen inside and outside the furnace shall be as
given in Table 4 (see also Figures 3 and 9).
Table 4 — Minimum length of test specimen
Orientation Minimum length (m)
Inside furnace Outside furnace
Horizontal 3,0 4,2
Vertical 2,0 4,25
7.1.3 Cross-section
The standard sizes of ducts given in Table 5 shall be tested unless only smaller cross-sections
are used:
Table 5 — Internal cross-section of test specimen (dimension of the open cross-section)
Rectangular Circular
Width (mm) Height (mm) Diameter (mm)
1000 ± 10 250 ± 10 560 ± 10
7.2 Number
A minimum of one test specimen shall be tested. For horizontal and vertical installation see 14.2.
7.3 Design
7.3.1 General
The test shall be made on a test specimen representative of the complete duct assembly,
including integral or intended insulation on which information is required. Each type of duct
requires a different approach and the laboratory shall as far as practical reproduce the edge
conditions and the method of fixing or support inside and outside the furnace to that
representative of that used in practice. The distance between hangers or supports shall also be
representative.
7.3.2 Openings in duct
Two openings equal in size shall be provided, one on each vertical side of the duct inside the
furnace. For horizontal ducts the openings shall be positioned (500 ± 25) mm from the end of
the duct inside the furnace (see Figures 1). For vertical ducts the openings shall be positioned
(200 ± 10) mm below the furnace roof (see Figure 2).
In both vertical and horizontal ducts, clear openings shall have the same width/height ratio as
the cross-section of the duct. For circular ducts, the openings shall be rectangular with a
width/height ration of 4:1. The total area of the openings shall be 50 % ± 10 % of the internal
cross sectional area of the duct. Framing of the openings shall be as in practise (to avoid
weakening the duct walls in the area around the openings).
7.3.3 Joints in horizontal ducts
The test configuration shall include at least one joint inside the furnace and at least one joint
outside it. There shall be at least one joint in every layer of fire protection material (if
applicable), both inside and outside the furnace and in any steel duct.
Outside the furnace, the joint in the outer layer of the fire protection material shall be no further
than 700 mm from the supporting construction and no nearer than 100 mm to thermocouples
T2. Inside the furnace, the joint in the outer layer of fire protection material shall be located at
approximately mid-span.
The distance between joints and suspension devices shall not be less than that used in practice.
If the minimum distance has not been specified, suspension devices shall be arranged so that the
joint of the outermost layer at the bottom of the insulation material (if no insulation material is
present: joint of the steel duct) lies midway between them. Centres of the suspension devices
shall be specified by the manufacturer and shall be representative of practice.
7.3.4 Joints in vertical ducts
The test configuration shall include at least one joint inside and one joint outside it.
There shall be at least one joint for every layer of fire protection material, both inside and
outside the furnace and in any steel duct.
Outside the furnace, the joint in the outer layer of the fire protection material shall be no further
than 700 mm from the supporting construction and no nearer than 100 mm to thermocouples
T2. Inside the furnace, the joint in the outer layer of fire protection material shall be located at
approximately mid-span.
7.3.5 Support for vertical ducts
Vertical ducts shall be supported on the furnace floor and penetrate through the supporting
construction (see Figure 2); the ducts shall be fixed at the level of the supporting construction as
they would be fixed in practice when penetrating a floor. This shall be as specified by the
sponsor.
7.3.6 Compensators
Where compensators are used in practice then they shall be incorporated in the test specimen.
In this case the compensator shall be located outside the furnace approximately 500 mm from
the perforated plate.
7.3.7 Access panels
Where access panels are used in practice then they shall be incorporated in the test specimen. In
this case the access panels shall be located outside the furnace approximately 500 mm
downstream from the perforated plate. In cases where compensator and access panel are
included in one test specimen, the placement of the compensator takes precedence (access
panel shall be located (300 ± 50) mm from the end of the compensator or in the next section
downstream).
In cases where access panel are included in the test specimen causing conflicts with the joints in
the different layers of the duct, the placement of the joints takes precedence. In that case move
the access panel further downstream.
8 Installation of test specimen
8.1 General
The test specimen shall be installed, as far as possible, in a manner representative of its use in
practice.
The supporting construction selected shall be a wall, partition or floor either selected from the
standard supporting constructions in chapter 8.2 or of the type to be used in practice which
shall have a classified fire resistance equal or greater than the intended fire resistance of the
duct being tested.
Where the duct passes through an opening in the furnace wall or roof, then the opening shall be
of sufficient dimensions to allow for the supporting construction to surround all faces of the
duct by at least 200 mm in case of rigid supporting constructions.
In case of flexible supporting walls, the flexible walls shall have minimum dimensions of
2500 mm x 2500 mm and have one fixed and one free vertical edge (for free edge cf.
EN 1364-1:2015, 6.3.2). The horizontal clear spacing between the outer edge of the penetration
and the free edge of the flexible supporting construction shall be (500 ± 50) mm. The clear
vertical spacing between the top of the flexible supporting construction and the top of the outer
edge of the penetration shall be at least 500 mm.
Ducts shall be arranged as shown in Figures 1 and 2. The end of the duct within the furnace shall
be closed independently of any furnace enclosure by materials and construction similar to the
remainder of the duct.
8.2 Standard supporting construction
A standard supporting construction shall be selected from the specifications detailed in
EN 1366-1. Where the duct passes through an opening in the furnace wall, then the opening
shall be of sufficient dimensions to allow for the supporting construction to surround all faces of
the duct by at least 200 mm from the duct or the outside edge of any fire stopping.
To ensure that leaking furnace gas does not affect the duct leakage measurement it is important
that the all gaps between test specimen, supporting construction and all parts of the furnace are
well sealed.
8.3 Restraint of ducts
8.3.1 Inside the furnace
All ducts shall be fully restrained in all directions at the furnace wall or floor remote from the
penetration point. Where there is the possibility of the furnace wall moving then the fixings shall
be made independently of the furnace structure.
8.3.2 Outside the furnace
The horizontal duct shall be restrained outside the furnace. The restraining point shall be
located at a position (500 ± 50) mm from the end of the duct and shall provide restraint on
movement in horizontal directions but shall allow movement in vertical directions (see
Figure 8). The frame used to apply the restraint shall be rigid and have sufficient strength to
resist all horizontal forces.
Vertical ducts shall be unrestrained outside the furnace. For test purposes the horizontal
movement of the top edge of the vertical duct shall be prevented.
9 Conditioning
9.1 General
Conditioning of the test construction shall be in accordance with EN 1363-1.
9.2 Water-based sealing materials
Water-based materials (e.g. mortar, concrete …) used to seal the gap between the supporting
construction and the duct where the gap is ≤ 25 mm wide shall be conditioned for at least seven
days before fire testing.
Water-based materials used to seal the gap between the supporting construction and the duct
assembly where the gap is > 25 mm wide shall be conditioned for at least 28 days before fire
testing.
10 Application of instrumentation
10.1 Thermocouples
10.1.1 Furnace thermocouples (plate thermometers)
Plate thermometers shall be provided in accordance with EN 1363-1 and shall be positioned as
shown in Figures 9 (horizontal ducts) and 10 (vertical ducts).
For all ducts the plate thermometers shall be oriented so that side A faces the walls of the
furnace opposite the duct being evaluated.

10.1.2 Unexposed surface thermocouples
Guidance on thermocouples at the point of penetration of the duct through the wall or floor is
shown in EN 1366-1 for typical penetration details.
The application of the thermocouples is optional for the manufacturer to request them. They
will not be used for classification.
10.1.3 Gas temperature adjacent to nozzles
The gas temperature adjacent to the nozzles shall be measured with the thermocouples
arranged pointing downwards to allow for draining moisture. The thermocouple measuring
junction shall be located at the centre line of each nozzle and at a distance equal to twice the
diameter of the measuring duct downstream from the entrance to the flow measuring device
shown on Figure 6 and 7, item no. 6.
10.2 Pressure
10.2.1 Furnace pressure
Furnace pressure shall be measured in accordance with Clause 6.
10.2.2 Differential under-pressure in duct
For measurement of the differential pressure between the inside and outside the of duct, the
pressure probe shall be located horizontally 50 mm from the end of the duct in level with the
centre line of the inlet nozzles as shown in Figures 6 and 7 as item no. D1. (pressure sensor in
accordance with 5.6 or alternative a four-point-measurement –piezometric-ring).
10.3 Oxygen measurements
Oxygen measurements are made using a probe manufactured from stainless steel tube, having
approximate dimensions 6 mm outside diameter and 5 mm internal diameter. The open end
shall be located inside the duct 100 mm upstream from the perforated plate on the centre line of
the duct (first sensor). A second probe (second sensor) shall be located after the nozzles at a
distance of 100 mm on the centre line of the connecting duct (see Figures 6 and 7 for details).
Each probe is connected by suitable pipework to its own oxygen measuring system. The position
of the oxygen sensors is shown on Figures 6 and 7, item G1 and G2.
Each probe is connected by suitable pipework to its own oxygen measuring system.
Alternative the oxygen sensors can be manufactured from stainless steel tube, 1200 mm long,
having approximate dimensions 10 mm outside diameter and 8 mm internal diameter. In that
half opposite to the open end of the tube there are 20 wholes of 3 mm diameter and on the half
near to the open end of the tube 20 wholes of 2 mm diameter. The wholes are spaced 20 mm
(see Figure 14). The tube is installed into the wall with the wholes pointing downward the flow.
For mounting the tube inside the duct a block is fixed to the duct wall to support the closed end
of the tube. This second probe shall be located 150 mm upstream from the duct end at mid
height on the centre line.
10.4 Deflection measurement for determination of reduction in internal cross
section area
The reduction in internal cross-section area shall be determined in 3 locations outside the
furnace, during the test at ambient temperature and during the fire test.
The three selected cross-section locations shall not be effected by the perforated plate or the
end of the duct. The locations shall be selected where the largest reductions are anticipated.

If a compensator is included in the test the measurement as described above shall be performed
in addition on the compensator.
The surface deflection pattern seen during the test at ambient temperature should be used as
guideline for the selection of locations.
NOTE If the test specimen consists of a steel duct with an insulating cladding, the reduction of the
internal cross-sections is measured by using pins with fixed washers.
For rectangular and circular ducts four deflection measurements are taken at each cross-section,
midway on each of the sides as shown on Figure 15 and 16.
The internal cross-sections reduction is then for each section calculated in the following way:
Internal Cross Section Reduction (ICSR)
AA−
NR
ICSR ⋅ 100
A
N
where
A is the nominal area
N
A is the reduction area
R
A of a rectangular duct:
N
AW⋅ H
N norm norm
A of a circular duct:
N
A= ⋅π⋅ W ⋅ H
( )
N norm norm
A of a rectangular duct:
R
AW⋅⋅ H − H+ H ⋅⋅ W − W
( ) ( )
R norm norm x norm norm x
A of a circular duct:
R
A= ⋅π⋅ W ⋅ H − WH⋅
( )
R norm norm x x
Where
W W −−X X
x norm 13
H H −−XX
x norm 2 4
Four measurements shall also be used for reduction in internal cross-section area for circular
ducts. The measurements should be perpendicular to the duct surface for every 90° angle. The
shape of the duct is assumed to be parabolic when calculating the area reduction for circular
ducts.
To be able to measure any deflection an, initial reference value shall be determined before the
under-pressure is applied to the duct.
These values are defined as the initial deflection values.

=
=
=
=
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11 Test procedure
11.1 General
The test procedure is divided into the following steps:
1 pre-test calibration of the perforated plate;
2 test at ambient temperature;
3 pre-fire test procedures;
4 fire test.
11.2 Pre-test calibration of the perforated plate
The test is performed with the openings un-sealed.
Switch on the extraction fan. Check that both the required differential pressure and air velocity
of 2 m/s are obtained under ambient conditions. Ensure the air velocity is within ± 15 % and the
differential pressure is within ± 3 %. However, if these values cannot be achieved, switch off the
fan, remove the perforated plate and as appropriate, drill additional holes or seal some holes
using screws. Replace the perforated plate and repeat the procedure until the required values
have been achieved.
NOTE The initial check on the perforated plate can be undertaken on a duct section provided for the
purpose and not the test specimen where the removal of the plate could create problems.
If the duct is installed in the furnace make sure that the furnace is open so that no under-
pressure can be formed inside the furnace. The differential pressure between the laboratory and
furnace shall be zero.
11.3 Test at ambient temperature
11.3.1 Seal the two openings on the ducts exposed side
11.3.2 Locations for determination of reduction in internal cross-section area are selected and
the initial deflection values are measured.
11.3.3 Switch on the extraction fan, making any fine adjustments so that the differential
pressure reading is within ± 3 % of the prescribed value given in Table 1 throughout the time
over which the ambient leakage measurements are taken.
NOTE The pressure level can be selected by the sponsor, alternatively it is possible to progressively
work up from pressure level 1 to pressure level 3, subject to compliance with 12.2.
11.3.4 For a period of five minutes measure and record the differential pressure over the
ambient leakage measuring device at the selected pressure level. Determine the volume flow in
m /h Calculate the leakage at ambient temperature (L ) as:
amb
volume flow [m³/h] m³
L
amb
Total internal surface area [m²] m²⋅ h
11.3.5 Determine the internal reduction in cross-section area at each location outside the
furnace.
==
Where information is required on leakage and reduction internal in cross-section area at other
pressure levels, repeat the procedure from 11.3.3 at the other pressure.
11.4 Pre-fire test procedures
11.4.1 Remove the seals from the openings
11.4.2 Calibrate the oxygen measuring instrument(s) at maximum one hour prior to the fire
test.
11.4.3 Measure the initial deflection values for determination of reduction in internal cross-
section area.
11.4.4 Switch on the extraction fan and make any adjustments to the damper or fan to maintain
the differential pressure at the selected pressure level given in Table 1.
11.5 Fire test
11.5.1 Ignite the furnace and commence the test as described in EN 1363-1.
11.5.2 Throughout the test, maintain the furnace conditions to comply with the requirements of
EN 1363-1. Make any adjustments necessary to maintain the differential pressure readings
inside the duct to within ± 3 % of the appropriate value given in the third column of Table 1
after 5 min of the start of the test.
11.5.3 Record all temperatures and pressures at the intervals specified in EN 1363-1.
11.5.4 Measure the deflection for determination of reduction in internal cross-section area
outside the furnace, at intervals not exceeding 15 min, and calculated the reduction.
11.5.5 After the first fifteen minutes of the test, start recording the oxygen measurements.
11.5.6 Take observations on the general behaviour of the duct throughout the test, in particular
look for the collapse of any part of the duct that would affect its ability to maintain its intended
function.
11.5.7 Using the values recorded, calculate the leakage under fire conditions (L ) from the O
f 2
measurements as follows:
C ⋅⋅m c − c
( )
fG2 G2 G1
m =
L
21− c
G1
where
m is the leakage mass flow (kg/s)
L
m is the mass flow at point G2 near inlet nozzles (kg/s)
G2
c is the oxygen content of first sensor (vol-%)
G1
21 is the oxygen concentration of ambient standard atmosphere (vol-%)
c is the oxygen content of second sensor (vol-%)
G2
C
is the correction factor, is determined as follows:
f
C is the 0,94 for liquid fuel (oil)
f
C is the 0,91 for gas
f
NOTE Gaseous fuel (natural gas H = high and L = low) with approximately 85 to 100 vol-%
concentration of methane (CH4), see Annex B and C.
The leakage volume flow V shall be calculated as:
L
m
L
V =
L
ρ
where
V is the leakage volume flow (m3/s)
L
ρ is the density of dry air at 20 °C/1013 hPa (= 1,2 kg/m )
The leakage under fire conditions (L ) used to determine compliance with the leakage criteria
f
stated in 12.3 shall be calculated as:
V [m³/h]
m³
L
L
f
Internal surface area with underpressure [m²] m²⋅ h
Where internal surface area with under-pressure is defined as the surface area of the duct from
the perforated plate to the end of the duct by the inlet nozzles including the endplate where the
nozzles is positioned and excluding the surface of the perforated plate
11.5.8 Termination of test
The test may be terminated:
a) due to safety reasons;
b) at the request of the sponsor;
c) at end of classification period (or if a serious failure occurs);
d) when a failure criterion is exceeded:
— integrity at penetration point;
— leakage (but this may need to be calculated after the test);
— if the duct inside the furnace collapses
— reduction of cross-section (confirmed after test).
12 Performance criteria
12.1 General requirements
Under the specified pressure conditions given in Table 1, the fire resisting smoke extraction
duct shall satisfy the leakage requirements given in 12.2 and 12.3.
The fire resisting smoke extraction duct shall fulfil the test and classification requirement
according to EN 1366-1 and EN 13501-3 as stated in the Scope.

==
Three pressure levels are used for smoke extraction ductwork. In the course of testing smoke
extraction ductwork in accordance with Clause 11, one of the pressure levels defined in Table 1
shall be used.
In relation to classification according to EN 13501-4, all the criteria stated in 12.2 and 12.3, with
the exception the insulation (12.3.4) and smoke-leakage (12.3.5) criteria imply failure of
integrity.
12.2 Criteria at ambient temperature
12.2.1 Ambient leakage
Smoke extraction ductwork of all categories intended for installation outside the enclosed space
from which smoke is to be extracted, shall not have an ambient leakage (L ) exceeding
amb
3 2
10 m /h per 1 m of total internal surface area of the complete duct (inside and outside the
furnace) when tested in accordance with 11.3.
12.2.2 Reduction in internal cross-section area under ambient conditions outside the
furnace
The reduction in internal cross-section area under ambient conditions of the smoke extracting
ductwork shall not decrease by more than 10 % in any of the measured cross-sections when
tested in accordance with 11.3.
12.3 Criteria under fire conditions
12.3.1 General
When tested in accordance with 11.4 smoke extraction ductwork for use in combination with
smoke exhaust fans and which is intended for use outside the enclosed space from which smoke
is to be extracted, shall comply with 12.3.2 to 12.3.7.
12.3.2 Leakage (Integrity)
3 2
The duct shall not have a leakage under fire conditions (L ) exceeding 10 m /h per 1 m of
f
internal surface area. This shall be related to the surface area of the duct from the perforated
plate to the end of the duct by the inlet nozzles.
12.3.3 Integrity
The integrity at the seal/penetration between the duct and the supporting construction shall be
judged in accordance with EN 1363-1.
12.3.4 Insulation
Test results from EN 1366-1 shall demonstrate the insulation performance of the duct.
12.3.5 Smoke-Leakage
3 2
The duct shall not have a leakage under fire conditions (L ) exceeding 5 m /h per 1 m of
f
internal surface area. This shall be related to the surface area of the duct from the perforated
plate to the end of the duct by the inlet nozzles.
12.3.6 Reduction in internal cross-section area under fire conditions
The reduction in internal cross-section area under fire conditions of the smoke extracting
ductwork shall not decrease by more than 10 % in any of the measured cross-sections when
tested in accordance with 11.4.

oSIST prEN 1366-8
...