ISO 21925-1:2018

INTERNATIONAL ISO
STANDARD 21925-1
First edition
2018-11
Fire resistance tests — Fire dampers
for air distribution systems —
Part 1:
Mechanical dampers
Reference number
©
ISO 2018
© ISO 2018
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Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles of the test . 2
5 Apparatus . 3
6 Test construction .12
6.1 General .12
6.1.1 Side to be tested.12
6.1.2 Dampers installed in both walls and floors .13
6.1.3 Dampers installed within a structural opening .13
6.1.4 Dampers mounted onto face of wall or floor. .13
6.1.5 Dampers remote from wall or floor .13
6.1.6 Minimum separation between dampers .13
6.2 Size of specimen .13
6.3 Thermal release mechanism .15
6.4 Specimen installation .15
6.5 Supporting construction .16
6.5.1 Principles .16
6.5.2 Recommended supporting constructions .16
6.6 Conditioning .17
7 Determination of leakage of connecting duct and measuring station.17
8 Determination of leakage at ambient temperature .18
9 Fire test .18
10 Classification and criteria .19
10.1 Number of tests required .20
11 Test report .21
12 Direct field of application of the test results .22
12.1 Size of fire damper .22
12.2 Fire dampers installed within structural openings .22
12.3 Fire dampers mounted onto the face of a wall .22
12.4 Fire dampers remote from a wall or floor .22
12.5 Separation between fire dampers and between fire dampers and construction
elements .22
12.6 Supporting constructions .22
Annex A (informative) Historical background of the test methods .24
Annex B (informative) Alternative thermal release mechanisms .27
Annex C (informative) Test of thermal release mechanisms .28
Annex D (informative) Reliability tests for thermal release mechanisms .37
Bibliography .39
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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 2, Fire
containment.
This first edition of ISO 21925-1 cancels and replaces ISO 10294-1:1996, ISO 10294-2:1999,
ISO 10294-3:1999 and ISO 10294-4:2001, which have been technically revised.
The main changes are as follows:
— integration of the requirements for mechanical dampers, which were published as four separate
parts in the former ISO 10294-series, into a single document.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved

Introduction
The material in the former ISO 10294-series was used to assess the fire resistance of mechanical fire
dampers. The separate publications required multiple maintenance work and resources to keep them
current and up-to-date. By having the requirements in a single volume, ISO 21925-1 is intended to
improve efficiency and to be more user friendly. It is also anticipated that a single volume will serve
the continued efforts to promote the alignment of the requirements contained in regional and national
standards for testing fire dampers against this document.
ISO 10294-1:1996 addressed the spread of fire and smoke in buildings through ventilation ducts and
other openings in fire-separating walls and floors.
ISO 10294-2:1999 provided classification, criteria and field of application for the test method given in
ISO 10294-1:1996.
ISO 10294-3:1999 provided a background to the test method and a rationale to the procedures and the
criteria selected with respect to the testing of fire dampers, as given in ISO 10294-1:1996.
ISO 10294-4:2001 provided a test method to evaluate the performance of fire damper-operating
mechanisms.
A list of all parts in the ISO 21925-series can be found on the ISO website.
INTERNATIONAL STANDARD ISO 21925-1:2018(E)
Fire resistance tests — Fire dampers for air distribution
systems —
Part 1:
Mechanical dampers
SAFETY WARNING — For suitable health precautions to be taken, the attention is drawn to the
possibility that toxic or harmful gases can be released while the test is being conducted.
1 Scope
This document specifies a test method for the determination of the resistance of fire dampers to heat,
and for the evaluation of their ability to prevent fire and smoke spreading from one fire compartment
to another through an air distribution system.
It is applicable to mechanical fire dampers. It is not intended to be used for dampers used only in smoke
control systems, for testing fire protection devices which only deal with air transfer applications, or
for dampers used in suspended ceilings, as the installation of the damper and duct can have an adverse
effect on the performance of the suspended ceiling, requiring other methods of evaluation.
NOTE "Air transfer" is a low-pressure application through a fire separation door (or wall, floor) without any
connection to an air duct.
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.
ISO 834-1, Fire resistance tests — Elements of building construction — Part 1: General requirements
ISO 5167-7, Measurement of fluid flow by means of pressure differential devices — Part 7: Orifice plates,
nozzles and Venturi tubes inserted in circular cross-section conduits running full
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 https: //www .iso .org/obp
3.1
test construction
complete test assembly, consisting of the separating element, damper and duct sections and penetration
seals (if any)
3.2
supporting construction
wall partition or floor into which the damper and duct section are installed for the test
3.3
separating element
wall, partition or floor into which the damper and duct are installed in the building
3.4
connecting duct
duct section between the damper or separating element and the measuring station
3.5
measuring station
equipment consisting of pipe system with an orifice plate or venturi and an air flow straightener (if
any), installed between the connecting duct and the exhaust equipment to determine the volume flow
rate of gases passing through the damper under test
3.6
exhaust equipment
equipment consisting of a fan and balancing or dilution dampers (if any), to apply and maintain the
underpressure in the connecting duct
3.7
fire damper
mobile closure within a duct which is operated automatically or manually and is designed to prevent
the spread of fire
3.8
actuating mechanism
mechanism, integral or directly associated with the damper which, when initiated by the
damper triggering device, causes the movable component of the damper to change from the "open" to
the "closed" position
3.9
insulated damper
damper which satisfies the integrity, leakage and insulation requirements of this document
3.10
uninsulated damper
damper which satisfies the integrity and leakage requirements of this document
3.11
thermal release mechanism
system which evaluates the parameters of temperature in the airflow of the ventilation duct and
initiates the closing of the fire damper before a predicted threshold limit is reached
Note 1 to entry: The sensing element may be, for example, a fusible link, memory metal, frangible bulb or
electrical sensor.
3.12
threshold limit
maximum operational temperature of the thermal release mechanism
4 Principles of the test
The damper with its fixing device is built into, or attached directly, or remotely via a section of ducting,
to a fire-separating building element in a manner representative of good practice. Tests are performed
starting with the damper in the open position so as to expose the actuating mechanism of the damper
to furnace conditions. Temperature and integrity measurements are carried out in various parts of
the test construction during the test. The tightness of the damper system is measured by direct flow
measurements whilst maintaining a constant pressure differential across the closed damper of 300 Pa.
For special applications, higher underpressures may be employed. The tightness of the damper in the
closed position is also measured at ambient temperature prior to the start of the furnace test.
2 © ISO 2018 – All rights reserved

As the test conditions and tolerances for the beginning of the fire test are not specified in detail, the fire
test enables only a limited assessment of the actuating mechanism to be carried out.
Annex A gives the historical background of the test.
5 Apparatus
The test apparatus specified in 5.1 to 5.8, including the instrumentation, shall be in accordance with
ISO 834-1 except where specifically stated otherwise.
An example of a test arrangement is shown in Figure 1.
5.1 Furnace, capable of achieving the heating and pressure conditions specified in ISO 834-1.
5.2 Damper under test, attached to the connecting duct in accordance with the manufacturer’s
instructions.
5.3 Connecting duct, of all welded construction fabricated from (1,5 ± 0,1) mm thick steel with a
width and height appropriate to the size of the damper under test. The duct shall have a length of 2× the
diagonal dimension of the damper, up to a maximum of 2 m. The connecting duct shall be provided with
a gas-tight observation port.
5.4 Measuring station, consisting of an orifice plate, venturi, or other suitable device, an air flow
straightener (if required) and straight lengths of pipe sized in accordance with ISO 5167-1 installed
between the connecting duct and the exhaust fan to determine the volume flow rate of gases passing
through the damper under test. When testing dampers installed in floors, it is still possible to use the
measuring station horizontally. A suitable mounting detail is shown in Figure 2.
5.5 Exhaust fan system, capable of controlling flow rates and maintaining a pressure difference
between the connecting duct and the furnace, as required, when the damper is closed.
Regardless of what test pressure is chosen, the fan should be capable of achieving a 200 Pa pressure
difference higher than the test pressure difference chosen for the test.
Regulation of the 300 Pa (or higher pressure differential) may be by means of a dilution damper installed
just before the fan inlet. The pressure shall be controlled to within ±5 % of the required pressure. A
balancing damper shall be fitted at the outlet of the fan to adjust the pressure range of the systems to
suit the damper under test. A variable speed fan may be used instead of the dilution damper.
5.6 Instrumentation for measuring and recording the furnace temperature, in accordance with
ISO 834-1. Locations of the furnace thermocouples for a number of different test arrangements are
shown in Figures 3, 4, 5, 6, 7 and 8.
The gas temperature adjacent to the flow measuring device shall be measured by a 0,25 mm bare
wire thermocouple enclosed in a 6 mm diameter porcelain twin wall tube with its measuring junction
located at the centreline of the measuring duct and at a distance equal to twice the diameter of the
measuring duct downstream from the flow measuring device. A similar thermocouple shall be located
at the exit from the connecting duct plenum (see Figures 1 and 2). Alternative thermocouples may be
used provided it can be shown that they have equivalent response time.
5.7 Instrumentation for measuring and recording surface temperature, in accordance with
ISO 834-1.
It shall be located, depending on the method of mounting the damper selected, in the positions shown in
Figures 3, 4, 5, 6, 7 or 8.
5.8 Instrumentation for measuring pressure differential between the furnace and the
connecting duct.
A pressure tapping shall be located on the centreline of one vertical side wall of the connecting duct.
Instrumentation shall have a 300 Pa measurement capacity higher than the test pressure chosen for the
test. Instrumentation shall also be provided for measuring the pressure difference between inside and
outside (ambient) of the furnace.
5.9 Timing device, capable of running throughout the test period.
5.10 Gap gauges and cotton pad, according to ISO 834-1, to judge the integrity of the joints between
the damper and its connecting duct and the damper assembly and the supporting construction of the test
arrangement.
4 © ISO 2018 – All rights reserved

Key
1 supporting construction (wall)
2 2× diagonal (to a maximum of 2 m)
3 pressure sensor (on centreline)
4 observation port
5 orifice plate or venturi
6 pressure differential (300 Pa)
7 pressure differential control box
8 pressure sensor in laboratory
9 pressure control dilution damper
10 pneumatic actuator or manual control
11 balancing damper
12 fan
13 flexible connecting duct
14 support
15 thermocouple
16 support
17 flow straightener
18 flange
19 support
20 thermocouple at exit from plenum
21 connecting duct
22 test damper
23 furnace chamber
24 pressure sensor (on centreline of damper)
25 distance: thermocouple to orifice plate = 2 d
Figure 1 — Example of general test arrangement
Key
1 dimension equal to the diameter of the measuring station
2 pressure sensor
3 pressure differential (300 Pa)
4 pressure sensor in laboratory
5 pressure differential control box
6 pressure control dilution damper
7 balancing damper
8 fan
9 pneumatic actuator or manual control
10 flexible connecting duct
11 distance: thermocouple to orifice plate = 2 d
12 thermocouple
13 support
14 orifice plate or venturi
15 flange
16 connecting duct
17 thermocouple at exit from plenum
18 flow straightener
19 support
20 supporting construction {floor)
21 furnace chamber
22 test damper
23 pressure sensor
24 2× diagonal (to a maximum of 2 m)
Figure 2 — Example of an alternative arrangement when testing dampers in floors
6 © ISO 2018 – All rights reserved

Dimensions in millimetres
Key
1 furnace
2 supporting construction
3 support
4 connecting duct
5 connecting angle
6 length "L" to be specified by damper manufacturer
7 infill material, provided it is necessary
8 damper
9 insulated ductwork
10 furnace thermocouples, 4 places
T , T , T unexposed surface thermocouples (minimum of one each side)
s 1 2
Figure 3 — Position of surface thermocouples when damper is installed in an insulated duct
Dimensions in millimetres
Key
1 furnace
2 supporting construction
3 support
4 connecting duct
5 connecting angle
6 infill material, provided it is necessary
7 damper
8 furnace thermocouples, 4 places
L length to be specified by damper manufacturer
T , T , T unexposed surface thermocouples (minimum of one each side)
s 1 2
Figure 4 — Position of surface thermocouples when damper is installed in a non-insulated duct
8 © ISO 2018 – All rights reserved

Dimensions in millimetres
Key
1 furnace
2 supporting construction
3 support
4 connecting duct
5 damper
6 furnace thermocouples, 4 places
T , T , T unexposed surface thermocouples (minimum of one each side)
s 1 2
Figure 5 — Damper mounted onto face of supporting construction within the furnace
Dimensions in millimetres
Key
1 supporting construction
2 support
3 connecting duct
4 damper
5 connecting angle
6 furnace
7 furnace thermocouples, 4 places
L length to be specified by damper manufacturer
T , T , T unexposed surface thermocouples (minimum of one each side)
s 1 2
Figure 6 — Damper mounted onto face of supporting construction outside the furnace
10 © ISO 2018 – All rights reserved

Dimensions in millimetres
Key
1 furnace
2 floor for example
3 suitable attachment as in practice
4 insulation, provided it is necessary
5 insulated duct
6 supporting construction
7 support
8 connecting duct
9 connecting angle
10 damper
11 furnace thermocouples, 4 places
T , T , T unexposed surface thermocouples (minimum of one each side)
s 1 2
Figure 7 — Damper mounted remote from the supporting construction and within the
furnace chamber
Dimensions in millimetres
Key
1 furnace
2 supporting construction
3 damper insulation, provided it is necessary
4 damper
5 support
6 connecting duct
7 connecting angle
8 connecting angle
9 insulated duct
10 furnace thermocouples, 4 places
L length to be specified by damper manufacturer
L length of insulation where insulation is necessary
i
T , T , T unexposed surface thermocouples (minimum of one each side)
s 1 2
Figure 8 — Damper mounted remote from the supporting construction and outside the
furnace chamber
6 Test construction
6.1 General
The test construction shall contain all construction details relevant for test results. Only a maximum of
two dampers may be tested at one time.
6.1.1 Side to be tested
Where dampers are asymmetrical, they shall be tested from both sides, as it is probably not possible to
determine which side will give the worse result. Symmetrical dampers need only be tested from one
12 © ISO 2018 – All rights reserved

side. For the purposes of determining whether a damper is symmetrical, the presence of the actuating
mechanism can be ignored. However, in such a case, the damper shall be installed so that the actuating
mechanism is on the side away from the furnace, as this is considered to be the more onerous condition
because, as it will be further from the furnace, the time to its operation will be consequently longer.
If testing is carried out from one side only (i.e. one specimen) the reason for this shall be clearly stated
in the report.
6.1.2 Dampers installed in both walls and floors
Dampers which are to be employed in both walls and floors shall be tested in both orientations, unless
it can be demonstrated that one is more onerous.
6.1.3 Dampers installed within a structural opening
Dampers to be positioned within a structural opening shall be tested as shown in Figure 1 when
installed in a wall and as shown in Figure 2 when installed in a floor.
6.1.4 Dampers mounted onto face of wall or floor.
Uninsulated dampers mounted on a wall or floor and attached to the face of a structure shall be tested
with the damper positioned within the furnace as shown in Figure 5. Insulated dampers shall be tested
from both sides so that the insulation properties of the damper body and where appropriate the duct
can be evaluated. An example of a damper mounted to the wall/floor outside the furnace is shown in
Figure 6.
6.1.5 Dampers remote from wall or floor
6.1.5.1 Within the furnace
Dampers mounted remote from the wall or floor and separate from the structure shall be attached to
a length of ductwork. For test purposes, the duct shall be attached to the supporting construction with
the damper installed at the duct end within the furnace, as shown in Figure 7. This length of ductwork
shall be (150 ± 50) mm long and insulated to the extent necessary to ensure that it remains intact
throughout the test. The distance between the outer surface of the duct and the furnace wall or floor
shall not be less than 500 mm.
6.1.5.2 Outside the furnace
For dampers that are to be mounted onto a section of duct outside the furnace, as shown in Figure 8, the
length of duct shall be (500 ± 50) mm.
NOTE In the case of an uninsulated damper, mounted on a section of a duct outside the furnace, this does not
need to be tested.
6.1.6 Minimum separation between dampers
Where two dampers are to be tested at the same time, the distance between the dampers shall not be
less than 200 mm, as shown in Figure 9. Where the dampers are mounted in a wall or partition, but are
not located in the same horizontal plane, the required furnace pressure is determined at the horizontal
plane of the lower damper [see 9.8 a) and Figure 1.
6.2 Size of specimen
The largest size damper should be fire tested and, provided the damper satisfies the appropriate fire
leakage criteria, the results can be extended to smaller sizes of dampers whose dimensions relative
to width, height and length are smaller than that tested, subject to the following verification that all
components, in particular the damper blade(s), are the same thickness and cross-sectional shape with
respect to curtain and multi-blade dampers and blade width.
Dimensions in millimetres
Key
1 supporting construction
2 damper
Figure 9 — Maximum separation between two dampers
14 © ISO 2018 – All rights reserved

Dimensions in millimetres
Key
1 supporting construction (wall)
2 damper
3 pressure of 15 Pa maintained on this plane
Figure 10 — Dampers mounted in different horizontal planes
6.3 Thermal release mechanism
The thermal release mechanism shall be included in the specimen construction. If there are alternative
release mechanisms where these are in series with the basic thermal release and can be shown to not
inhibit the basic release then only the one thermal release mechanism is required to be tested. (See
optional requirements in Annexes B, C and D)
NOTE Where a damper design is modified solely with respect to the thermal release mechanism, it is not
necessary to continue the test after closure provided that the release mechanism does not affect the maintenance
of the closed state of damper.
6.4 Specimen installation
The dampers shall be installed as in practice in a supporting construction using methods which are in
accordance with the manufacturer's instructions. Damper manufacturers requiring the damper to be
tested in a length of insulated ductwork shall specify the length over which the duct is to be insulated
as shown in Figure 3.
6.5 Supporting construction
6.5.1 Principles
6.5.1.1 The supporting construction shall be a wall, partition or floor of the type to be used in practice.
6.5.1.2 A test result obtained for a fire damper mounted in a supporting construction made of masonry,
concrete or solid partition (without any cavity) is applicable for the same type of supporting construction
with a thickness and density equal to or greater than those of the supporting construction used for the test.
6.5.1.3 The supporting construction selected shall have fire resistance slightly greater than the
required fire resistance of the damper being tested.
6.5.1.4 If a specific supporting construction different than those described above is selected, the test
results obtained are applicable only to that specific wall, partition or floor.
6.5.2 Recommended supporting constructions
Where the type of supporting construction used in normal practice is not known, then one of the
standard supporting constructions described in Tables 1, 2 or 3 shall be used.
Table 1 — Standard rigid wall construction
Type of construction Thickness Density Test duration
mm kg/m t
h
Normal concrete/masonry 110 ± 10 2 200 ± 200 t = 2
150 ± 10 2 200 ± 200 2 < t ≤ 3
175 ± 10 2 200 ± 200 3 < t ≤ 4
a
Aerated concrete 110 ± 10 650 ± 200 t = 2
150 ± 10 650 ± 200 2 < t ≤ 4
a
This supporting construction may be made from blocks bonded together with mortar or adhesive.
Table 2 — Standard flexible-wall constructions (gypsum plasterboard)
Fire resistance Wall constructions
a b
Number of layers Thickness Insulation Thickness
min
on each side
mm D/ρ mm
30 1 12,5 40/40 75
60 2 12,5 40/40 100
90 2 12,5 60/50 125
120 2 12,5 60/100 150
180 3 12,5 60/100 175
240 3 15,0 80/100 190
a 3
D is the thickness in mm of mineral wool insulation inside the wall; ρ is the density in kg/m of mineral wool insulation
inside the wall.
b
Tolerance of ±10 %.
16 © ISO 2018 – All rights reserved

Table 3 — Standard floor constructions
Type of construction Thickness Density Test duration
mm kg/m t
h
Normal concrete 110 ± 10 2 200 ± 200 t = 1,5
150 ± 10 2 200 ± 200 1,5 < t ≤ 3
175 ± 10 2 200 ± 200 3 < t ≤ 4
Aerated concrete 125 ± 10 650 ± 200 t = 2
150 ± 10 650 ± 200 2 < t ≤ 4
6.5.2.1 Non-standard supporting constructions
When the test specimen is intended for use in a form of construction not covered by the standard
supporting constructions, it shall be tested in the supporting construction intended for use.
6.6 Conditioning
After installation of the damper into a supporting construction the assembly shall be subject to a
conditioning procedure in accordance with the requirements of ISO 834-1. The moisture content of the
supporting construction and any infill material used between the damper and supporting construction
may have an influence on the performance of the damper, in particular in relation to the insulation
criterion. Where practical, the moisture content of all the component items, including any infill material,
shall be controlled to ensure that equilibrium has been reached, and the final value measured and
recorded. If the supporting construction has been assembled and has been fully conditioned prior to
the installation of the test specimen and if a water based infill material (or other similar infill material
which requires curing) is used to seal any small gaps between the supporting construction and the
damper, then a minimum of 14 days shall be allowed for the assembly to reach equilibrium.
7 Determination of leakage of connecting duct and measuring station
7.1 Shut the damper manually and seal the inlet aperture using impervious material.
7.2 Assemble the connecting duct measuring station and exhaust fan as shown in Figure 1. The joints
between each component shall be well sealed with high temperature gaskets and/or sealants.
7.3 Connect an orifice plate, venturi or other suitable device to a suitable recording instrument
calibrated and complying with the requirements of ISO 5167-1. It may be necessary to use a different size
of orifice plate, venturi or other suitable device for the determination of the leakage of the connecting
duct and measuring standard to that used for the leakage tests described in Clauses 7 and 8. The leakage
is calculated from the recorded pressure differential from the orifice plate, venturi or other suitable
device using the formulae for volume flow rates given in ISO 5167-1.
7.4 Adjust the exhaust fan so that the air leakage through the connecting duct and measuring station
can be measured at 200 Pa, 300 Pa, 400 Pa and 500 Pa. The pressure differential at each value should
be maintained for 60 s before the leakage is recorded. For higher pressure differential than 300 Pa, the
control of leakage shall be performed at a test pressure 200 Pa higher than the test pressure chosen, in
five equal increments.
7.5 Plot the values on graph paper to determine the leakage at 300 Pa, or at a higher selected pressure
differential.
7.6 If the leakage at 300 Pa is more than 12 m /h, improve the sealing of joints and stability of test
construction until the leakage criterion referred to above can be met. For pressure differentials higher
than 300 Pa the leakage of 12 m /h may be increased by a factor (P /300) 0,5.
test
7.7 Remove sealing from the inlet aperture of the damper.
8 Determination of leakage at ambient temperature
8.1 Subject the damper to 50 opening and closing cycles.
8.2 After the 50th cycle, check that the damper still locks in the closed position and that it shows no
mechanical damage that will affect the operation of the damper.
8.3 Close the damper.
8.4 Adjust the exhaust fan to maintain an underpressure of 300 Pa (or higher underpressure) in the
connecting duct relative to the laboratory.
8.5 Record the pressure differential across the orifice plate, venturi or other suitable device at not
more than 2-min intervals for a period of 20 min or until stable readings are reached.
8.6 Calculate the leakage from the recorded pressure differential from the orifice plate, venturi or
other suitable device using the formulae for volume flow rates given in ISO 5167-1. Deduct the value
for the leakage of the connecting duct and measuring station determined in Clause 7 from the measured
leakage.
9 Fire test
9.1 Latch the damper into its open position, then if not already in position, mount the test specimen
onto the furnace.
9.2 Connect all instrumentation required by this document.
9.3 With the damper fully open, set the exhaust fan system to produce an air velocity of 0,15 m/s
across the damper opening. This may be measured by the orifice plate, venturi or other suitable device
located within the measuring duct. The air velocity shall be maintained to an accuracy of ±15 %.
9.4 Switch off the exhaust fan, but leave at its pre-set value given in 9.3.
9.5 Ignite the furnace. Start the timing device and switch on all measuring devices.
9.6 Switch on the exhaust fan as soon as the furnace has ignited.
9.7 When the damper has closed, adjust the exhaust fan to maintain an underpressure of 300 Pa (or
higher) in the connecting duct, relative to the furnace. Record the time at which the damper closes. If the
damper fails to close after 2 min from igniting the furnace, discontinue the test.
9.8 During the test, carry out the following.
a) Control and record the furnace temperature and pressure in accordance with ISO 834-1. The
furnace pressure at the horizontal centreline of a vertical damper shall be maintained at (15 ± 2) Pa.
18 © ISO 2018 – All rights reserved

b) Maintain a pressure differential between the connecting duct and furnace of (−300 ± 15) Pa, (or
higher underpressure}.
c) Record the pressure differential across the orifice plate, venturi or other suitable device and the
local gas temperature at not more than 2-min intervals.
Constants for orifice plate, venturi or other suitable devices shall be calculated in accordance with
ISO 5167-1 over the range of anticipated gas temperatures. As a function of time and measured gas
temperatures, select the corresponding orifice plate, venturi or other suitable device constants and
calculate the volume flow rate at the measuring station gas temperatures using the formulae for
volume flow rates given in ISO 5167-1. Correct the measured volume flow rate to 20 °C. Deduct the
value for the leakage of the connecting duct and measuring station determined in Clause 7 from the
measured leakages.
d) Record the temperature on the external surface of the connecting duct at the time intervals
specified in ISO 834-1.
e) The effect of gaps, orifices or openings on the integrity at the junction between the supporting
construction and connecting duct shall be determined by the use of the cotton pad and/or gap
gauges as defined in ISO 834-1.
f) Where practical, record any observations of the general behaviour of the damper assembly during
the test. In practice this is limited to observations taken on the furnace side and to the duct/damper
junction and adjacent area on the non-furnace side.
10 Classification and criteria
Depending on the classification required, the size of the fire damper to be tested and the criteria to be
applied are given in Table 4.
Table 4 — Fire test performance criteria
a
Classification Size to be tested Leakage at Fire test
ambient tempera-
Leakage limit Temperature Perimeter
ture
3 2 b
m /(h · m ) rise limit integrity
3 2
m /(h · m )
°C
Mean/Max.
c
E max. Not required 360 Not required GG/SF
c
ES max. 200 200 Not required GG/SF
min. 200 Not required Not required Not required
c
EI max. Not required 360 140/180 CP/GG/SF
c
EIS max. 200 200 140/180 CP/GG/SF
min. 200 Not required Not required Not required
In relation to the criteria for leakage (S), the values given shall be satisfied in both the ambient temperature (smallest
damper and largest damper in the range) and the fire test (largest damper in the range).
NOTE 1  The maximum temperature rise limit (180 °C) can be determined at any of the thermocouples T , T and T (or
1 2 s
the roving thermocouple described in ISO 834-1) and the mean (average) temperature rise (140 °C) is determined from
thermocouples T . Locations of the thermocouples are shown in Figures 3 to 8.
NOTE 2  For the purposes of calculating compliance with the leakage criteria in this table, the area of a damper can be
taken to be the cross-sectional area of the duct to which the damper is connected.
NOTE 3  Classification of integrity is according to whether or not the damper is also classified for insulation. Where a
damper is classified for integrity E and insulation I, the integrity is that determined by whichever of the three criteria fails
first. Where a damper is classified E but without an I classification, the integrity value is defined as the time to failure of
only the cracks/openings or sustained flaming criteria, whichever fails first.
a
E is the integrity (gas flow corrected to 20 °C);
I is the insulation (see note 1);
S is the leakage classification (see note 2) (gas leakage corrected to 20 °C).
b
CP is the cotton pad (see note 3);
GG is the gap gauge (see note 3);
SF is the sustained flaming (see note 3).
c
Leakage limits only apply after 5 min from the start of the test.
10.1 Number of tests required
The test method has been designed to cover as many potential applications for damper installation as
possible. It is not intended that all the options have to be covered in a test programme.
Guidance is given below in Tables 5 and 6 on the number of tests that may be required. Experience may
show that not all tests need to be undertaken, as some installation options may be found to represent
the most onerous condition, in which case the number of tests required can be reduced.
Table 5 — Fire damper standard installation application
Fire damper installation application in prac- Number of tests asymmetri- Number of tests symmet-
tice standard application cal fire damper rical fire damper
Installed within a wall 2 1
Installed within a floor 2 1
20 © ISO 2018 – All rights reserved

Table 6 — Fire damper special installation application
Fire damper installation application in Number of tests asymmetri- Number of tests symmetri-
practice special application cal fire damper cal fire damper
Installed on face of wall 2 1
Installed
...