ISO 7240-22:2017

Fire detection and alarm systems - Part 22: Smoke-detection equipment for ducts

ISO 7240-22:2017 specifies requirements, test methods and performance criteria for smoke-detection equipment for ducts (SDED) for use in fire detection and alarm systems installed in buildings (see ISO 7240‑1). The SDED samples the air from a duct and detects smoke in the sample. NOTE 1 A common method of operation is to use differential pressure arising from airflow in the duct. The SDED can use smoke detectors complying with ISO 7240‑7 or other detectors complying with tests specified in ISO 7240-22:2017. A common application for SDED is to detect visible smoke, for which detectors using scattered light or transmitted light can be more suitable. However, requirements for detectors using ionization are also included in ISO 7240-22:2017 for use in applications where detection of less visible fire aerosols is desired. For the testing of other types of smoke detectors or smoke detectors working on different principles, ISO 7240-22:2017 can be used for guidance. Smoke detectors with special characteristics, developed for specific risks, are not covered. NOTE 2 Certain types of detectors contain radioactive materials. The national requirements for radiation protection differ from country to country and are not specified in ISO 7240-22:2017.

Systèmes de détection et d'alarme d'incendie — Partie 22: Équipement de détection des fumées dans les conduits

General Information

• Status: Published
• Publication Date: 04-Sep-2017
• ICS: 13.220.20 - Fire protection
• Technical Committee: ISO/TC 21/SC 3 - Fire detection and alarm systems
• Drafting Committee: ISO/TC 21/SC 3 - Fire detection and alarm systems
• Current Stage: 9093 - International Standard confirmed
• Start Date: 15-Sep-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 15528:2020 - Paints, varnishes and raw materials for paints and varnishes - Sampling
• Effective Date: 06-Jun-2022
• Revises: ISO 7240-22:2007 - Fire detection and alarm systems - Part 22: Smoke-detection equipment for ducts
• Effective Date: 04-Nov-2015

Overview - ISO 7240-22:2017 (Smoke-detection equipment for ducts)

ISO 7240-22:2017 is an international standard that specifies requirements, test methods and performance criteria for smoke-detection equipment for ducts (SDED) used in building fire detection and alarm systems. It covers devices that sample air from HVAC or other ductwork and detect smoke in that sampled air. The standard describes allowed detector types (e.g., scattered-light, transmitted-light and ionization principles), common methods of sampling (such as differential-pressure sampling from duct airflow), and guidance for testing detectors that are not explicitly covered by other parts of ISO 7240.

Keywords: ISO 7240-22:2017, smoke-detection equipment for ducts, SDED, duct smoke detectors, fire detection and alarm systems.

Key topics and technical requirements

ISO 7240-22:2017 addresses technical and procedural areas essential to reliable duct smoke detection:

• Scope & definitions: Clarifies which SDEDs are covered and which special-purpose detectors are excluded.
• Performance requirements: Criteria for detector response behavior and repeatability/reproducibility of detections.
• Test methods: Detailed test procedures including environmental and operational tests such as:
  • dry heat, cold, damp heat (operational and endurance)
  • vibration, shock and impact
  • air leakage and smoke sensitivity
  • sulfur dioxide corrosion endurance
  • electromagnetic compatibility (EMC) immunity
  • dazzling/light interference tests
• Software and documentation: Requirements for software-controlled equipment, program storage and hardware/software documentation.
• Marking and data: Information that must be supplied with products and test reports.
• Compatibility with detector types: SDED may incorporate detectors complying with ISO 7240‑7 or follow ISO 7240‑22 test provisions for other principles, including ionization detectors.

Practical applications

ISO 7240-22 is used to ensure reliable early detection of smoke within building ductwork and HVAC systems. Typical applications:

• Early smoke detection in air-handling units and duct systems to prevent smoke spread.
• Protection of server rooms, cleanrooms, shopping centers, atria and corridors served by mechanical ventilation.
• Integration of duct detectors into building fire alarm strategies and smoke control systems.

Keywords: duct smoke detectors, HVAC smoke detection, air-handling unit safety.

Who should use this standard

• Manufacturers of duct smoke detectors and sampling equipment
• Test laboratories performing type and endurance tests
• Fire alarm system designers and installers specifying SDED for buildings
• Regulatory authorities and specifiers developing building safety and fire protection requirements

Related standards

• ISO 7240-1 (general requirements for fire detection and alarm systems)
• ISO 7240-7 (point-type smoke detectors) - referenced for compatible detector modules

This standard is essential for stakeholders seeking validated, tested duct smoke-detection solutions compliant with international test and performance criteria.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7240-22
Second edition
2017-09
Fire detection and alarm systems —
Part 22:
Smoke-detection equipment for ducts
Systèmes de détection et d'alarme d'incendie —
Partie 22: Équipement de détection des fumées dans les conduits
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Requirements . 2
4.1 Compliance . 2
4.2 Visual alarm indication . 2
4.3 Connection of ancillary devices . 2
4.4 Monitoring of detachable detectors . 3
4.5 Manufacturer's adjustments . 3
4.6 On-site adjustment of response behaviour . 3
4.7 Requirements for software-controlled smoke-detection equipment for ducts . 3
4.7.1 General. 3
4.7.2 Software design. 3
4.7.3 Storage of programs and data . 3
5 Tests . 4
5.1 General . 4
5.1.1 Atmospheric conditions for tests. 4
5.1.2 Mounting arrangements . 4
5.1.3 Operating conditions for tests . 4
5.1.4 Tolerances . 4
5.1.5 Response threshold value . 4
5.1.6 Provision for tests . 5
5.1.7 Test schedule . 6
5.1.8 Test report . 6
5.2 Repeatability . 6
5.2.1 Object of test . 6
5.2.2 Test procedure . 6
5.2.3 Requirements . 7
5.3 Reproducibility . 7
5.3.1 Object of test . 7
5.3.2 Test procedure . 7
5.3.3 Requirements . 7
5.4 Variation in supply parameters . 7
5.4.1 Object of test . 7
5.4.2 Test procedure . 8
5.4.3 Requirements . 8
5.5 Dazzling . 8
5.5.1 Object of test . 8
5.5.2 Test procedure . 8
5.5.3 Requirements . 9
5.6 Dry heat (operational) . 9
5.6.1 Object of test . 9
5.6.2 Test procedure . 9
5.6.3 Requirements .10
5.7 Cold (operational) .10
5.7.1 Object of test .10
5.7.2 Test procedure .10
5.7.3 Requirements .11
5.8 Damp heat, steady-state (operational).11
5.8.1 Object of test .11
5.8.2 Test procedure .11
5.8.3 Requirements .11
5.9 Damp heat, steady-state (endurance) .12
5.9.1 Object of test .12
5.9.2 Test procedure .12
5.9.3 Requirements .12
5.10 Sulfur dioxide, SO , corrosion (endurance) .13
5.10.1 Object of test .13
5.10.2 Test procedure .13
5.10.3 Requirements .13
5.11 Shock (operational) .14
5.11.1 Object of test .14
5.11.2 Test procedure .14
5.11.3 Requirements .14
5.12 Impact (operational) .15
5.12.1 Object of test .15
5.12.2 Test procedure .15
5.12.3 Requirements .15
5.13 Vibration, sinusoidal (operational) .16
5.13.1 Object of test .16
5.13.2 Test procedure .16
5.13.3 Requirements .17
5.14 Vibration, sinusoidal (endurance) .17
5.14.1 Object of test .17
5.14.2 Test procedure .17
5.14.3 Requirements .18
5.15 Air leakage .18
5.15.1 Object of test .18
5.15.2 Test procedure .18
5.15.3 Requirements .18
5.16 Electromagnetic compatibility (EMC) immunity tests (operational) .19
5.16.1 Object of test .19
5.16.2 Test procedure .19
5.16.3 Requirements .19
5.17 Fire sensitivity .20
5.17.1 Object of test .20
5.17.2 Test procedure .20
5.17.3 Requirements .21
6 Test report .21
7 Marking .22
8 Data .22
8.1 Hardware documentation .22
8.2 Software documentation .23
Annex A (normative) Smoke tunnel and fire test room arrangement
for response measurements .24
Annex B (normative) Test aerosol for response threshold value measurements .25
Annex C (normative) Smoke-measuring instruments .26
Annex D (normative) Apparatus for dazzling test .30
Annex E (normative) Apparatus for impact test .31
Annex F (informative) Air-leakage test apparatus .33
Annex G (normative) Rapid smouldering (pyrolysis) wood fire (TF2).34
Annex H (normative) Open plastics (polyurethane) fire (TF4) .37
iv © ISO 2017 – All rights reserved

Annex I (informative) Information concerning the construction of the smoke tunnel .39
Annex J (informative) Information concerning the construction of the measuring
ionization chamber .42
Bibliography .44
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 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire
fighting, Subcommittee SC 3, Fire detection and alarm systems.
This second edition cancels and replaces the first edition (ISO 7240-22:2007), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— in 5.16 (electromagnetic compatibility immunity tests), EN 50130-4 has been replaced by
IEC 62599-2;
— marking has been moved to a new Clause 7;
— data and software requirements have been moved to Clause 8.
A list of all parts in the ISO 7240 series can be found in the ISO website.
vi © ISO 2017 – All rights reserved

Introduction
Smoke-detection equipment for ducts (SDED) is used as part of a fire detection system to sample the
environment within air ducts of a building. Detection of smoke releases a signal to the connected
control and indicating equipment and can be used as a signal to an air-handling system to prevent the
spread of smoke within the building.
SDED is required to function satisfactorily not only in the event of a fire, but also during and after
exposure to conditions likely to be met in practice such as corrosion, vibration, direct impact, indirect
shock and electromagnetic interference. Some tests specified are intended to assess the performance of
the SDED under such conditions.
The performance of SDED is assessed from results obtained in specific tests. This document is not
intended to place any other restrictions on the design and construction of such equipment.
INTERNATIONAL STANDARD ISO 7240-22:2017(E)
Fire detection and alarm systems —
Part 22:
Smoke-detection equipment for ducts
1 Scope
This document specifies requirements, test methods and performance criteria for smoke-detection
equipment for ducts (SDED) for use in fire detection and alarm systems installed in buildings (see
ISO 7240-1).
The SDED samples the air from a duct and detects smoke in the sample.
NOTE 1 A common method of operation is to use differential pressure arising from airflow in the duct.
The SDED can use smoke detectors complying with ISO 7240-7 or other detectors complying with tests
specified in this document.
A common application for SDED is to detect visible smoke, for which detectors using scattered light or
transmitted light can be more suitable. However, requirements for detectors using ionization are also
included in this document for use in applications where detection of less visible fire aerosols is desired.
For the testing of other types of smoke detectors or smoke detectors working on different principles,
this document can be used for guidance. Smoke detectors with special characteristics, developed for
specific risks, are not covered.
NOTE 2 Certain types of detectors contain radioactive materials. The national requirements for radiation
protection differ from country to country and are not specified in this document.
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 209, Aluminium and aluminium alloys — Chemical composition
ISO 7240-1, Fire detection and alarm systems — Part 1: General and definitions
ISO 7240-7:2011, Fire detection and alarm systems — Part 7: Point-type smoke detectors using scattered
light, transmitted light or ionization
IEC 60068-1, Environmental testing — Part 1: General and guidance
IEC 60068-2-1, Environmental testing — Part 2: Tests. Tests A: Cold
IEC 60068-2-2, Environmental testing — Part 2: Tests. Tests B: Dry heat
IEC 60068-2-6, Environmental testing — Part 2: Tests — Test Fc: Vibration (sinusoidal)
IEC 60068-2-27, Environmental testing — Part 2: Test Ea and guidance: Shock
IEC 60068-2-42, Environmental testing — Part 2-42: Tests. Tests Kc: Sulphur dioxide tests for contacts and
connections
IEC 60068-2-78, Environmental testing — Part 2-78: Tests — Test Cab: Damp heat, steady state
IEC 62599-2, Alarm systems — Part 2: Electromagnetic compatibility — Immunity requirements for
components of fire and security alarm systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7240-1 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
response threshold value
A
th
aerosol density in the proximity of the specimen at the moment that it generates an alarm signal, when
tested as specified in 5.1.5
Note 1 to entry: The response threshold value may depend on signal processing in the detector and in the control
and indicating equipment.
4 Requirements
4.1 Compliance
In order to comply with this document, the SDED shall:
a) meet the requirements of Clause 4, which shall be verified by visual inspection or engineering
assessment;
b) be tested as specified in Clause 5, and shall meet the requirements of the tests;
c) meet the requirements of Clauses 7 and 8, which shall be verified by visual inspection.
4.2 Visual alarm indication
4.2.1 Each SDED shall be provided with a red visual indicator, by which the SDED can be identified
when the associated detector releases an alarm and which remains illuminated until the alarm condition
is reset. Where other conditions of the SDED can be visually indicated, they shall be clearly distinguishable
from the alarm indication, except when the SDED is switched into a service mode. The alarm indicator
may be the smoke detector indicator provided the indicator is visible when the detector is in situ as part
of the SDED.
4.2.2 The visual indicator shall be visible from a distance of 6 m in an ambient light intensity up to
500 lx at an angle of up to
a) 5° from the axis of the detector in any direction, and
b) 45° from the axis of the detector in at least one direction.
4.3 Connection of ancillary devices
The SDED may provide for connections to ancillary devices (remote indicators, control relays, etc.), but
open- or short-circuit failures of these connections shall not prevent the correct operation of the SDED.
2 © ISO 2017 – All rights reserved

4.4 Monitoring of detachable detectors
For detachable detectors, a means shall be provided for a remote monitoring system (e.g. the fire
detection control and indicating equipment) to detect the removal of the head from the base, in order to
give a fault signal.
4.5 Manufacturer's adjustments
It shall not be possible to change the manufacturer's settings except by special means (e.g. the use of a
special code or tool) or by breaking or removing a seal.
4.6 On-site adjustment of response behaviour
4.6.1 If there is provision for on-site adjustment of the response behaviour of the SDED, then
a) for all of the settings at which the manufacturer claims compliance with this document, the SDED
shall comply with the requirements of this document and access to the adjustment means shall be
possible only by the use of a code or special tool or by removing the SDED from its base or mounting;
b) any setting(s) at which the manufacturer does not claim compliance with this document shall be
accessible only by the use of a code or special tool, and it shall be clearly marked on the SDED or in
the associated data that if these setting(s) are used, the SDED does not comply with this document.
4.6.2 These adjustments may be carried out at the SDED, the detector or the control and indicating
equipment.
4.7 Requirements for software-controlled smoke-detection equipment for ducts
4.7.1 General
The requirements of 4.7.2 and 4.7.3 shall be met for SDED that rely on software control in order to fulfil
the requirements of this document.
4.7.2 Software design
In order to ensure the reliability of the SDED, the following requirements for software design shall apply.
a) The software shall have a modular structure.
b) The design of the interfaces for manually and automatically generated data shall not permit invalid
data to cause an error in the program operation.
c) The software shall be designed to avoid the occurrence of deadlock of the program flow.
4.7.3 Storage of programs and data
4.7.3.1 The program necessary to comply with this document and any preset data, such as
manufacturer's settings, shall be held in non-volatile memory. Writing to areas of memory containing
this program and data shall be possible only by the use of some special tool or code and shall not be
possible during normal operation of the detector.
4.7.3.2 Site-specific data shall be held in memory that retains data for at least two weeks without
external power to the SDED, unless provision is made for the automatic renewal of such data, following
loss of power, within 1 h of power being restored.
5 Tests
5.1 General
5.1.1 Atmospheric conditions for tests
Unless otherwise stated in a test procedure, the testing shall be carried out after the test specimen has
been allowed to stabilize in the standard atmospheric conditions for testing as described in IEC 60068-
1 as follows:
— temperature: (15 to 35) °C;
— relative humidity: (25 to 75) %;
— air pressure: (86 to 106) kPa.
The temperature and humidity shall be substantially constant for each environmental test where the
standard atmospheric conditions are applied.
5.1.2 Mounting arrangements
Mount the specimen by its normal means of attachment in accordance with the manufacturer's
instructions. If these instructions describe more than one method of mounting, then the method
considered to be least favourable shall be chosen for each test.
5.1.3 Operating conditions for tests
5.1.3.1 If a test method requires a specimen to be operational, then the specimen shall be connected
to suitable supply and monitoring equipment with characteristics as required by the manufacturer's
data. Unless otherwise specified in the test method, the supply parameters applied to the specimen shall
be set within the manufacturer's specified range(s) and shall remain substantially constant throughout
the tests. The value chosen for each parameter shall normally be the nominal value or the mean of the
specified range. If a test procedure requires a specimen to be monitored to detect any alarm or fault
signals, then connections shall be made to any necessary ancillary devices (e.g. through wiring to an end-
of-line device for collective detectors) to allow a fault signal to be recognized.
5.1.3.2 The details of the supply and monitoring equipment and the alarm criteria used shall be given
in the test report (Clause 6).
5.1.4 Tolerances
5.1.4.1 Unless otherwise stated, the tolerances for the environmental test parameters shall be as given
in the basic reference standards for the test (e.g. the relevant part of IEC 60068).
5.1.4.2 If a specific tolerance or deviation limit is not specified in a requirement or test procedure, then
a tolerance of ±5 % shall be applied.
5.1.5 Response threshold value
5.1.5.1 Install the specimen for which the response threshold value, A , is being measured in the
th
smoke tunnel described in Annex A, in its normal operating position, by its normal means of attachment.
NOTE This measurement can be taken only where the sampling apparatus of the SDED can fit inside the
smoke tunnel. Where the sampling apparatus is too large, it will be necessary to agree on other arrangements
with the manufacturer.
4 © ISO 2017 – All rights reserved

5.1.5.2 Before commencing each measurement, purge the smoke tunnel to ensure that the tunnel and
the specimen are free from the test aerosol.
5.1.5.3 Unless otherwise specified in the test procedure, the air temperature in the tunnel shall be
(23 ± 5) °C and shall not vary by more than 5 K for all the measurements on a particular SDED type.
5.1.5.4 Connect the specimen to its supply and monitoring equipment as specified in 5.1.3, and allow it
to stabilize for a period of at least 15 min, unless otherwise specified by the manufacturer.
5.1.5.5 Introduce the test aerosol, as specified in Annex B, into the tunnel such that the rate of increase
of aerosol density is as follows:
— for SDED incorporating detectors using scattered or transmitted light, in decibels per metre per
minute, as shown in Formula (1):
Δm
0,,015<<01 (1)
Δt
— for SDED incorporating detectors using ionization, per minute, as shown in Formula (2):
Δy
00,,50<< 3 (2)
Δt
NOTE These ranges are intended to allow the selection of a convenient rate, depending upon the sensitivity
of the SDED, so that a response can be obtained in a reasonable time.
5.1.5.6 The rate of increase in aerosol density shall be similar for all measurements on a particular
SDED type.
5.1.5.7 Conduct tests on the SDED specimen at each of the following air velocities:
a) the minimum specified by the manufacturer;
b) the maximum specified by the manufacturer;
c) the mean of the minimum and maximum.
5.1.5.8 The response threshold value is the aerosol density (in terms of m or y) at the moment that the
specimen gives an alarm at each air velocity. This shall be recorded as m, expressed in decibels per metre,
for detectors using scattered or transmitted light, or as y for detectors using ionization (as specified in
Annex C).
5.1.5.9 Designate the greater of the response threshold value as y or m for each air velocity; the
max max
lesser as y or m for each air velocity.
min min
5.1.6 Provision for tests
5.1.6.1 The following shall be provided for testing compliance with this document:
a) 13 SDED specimens;
b) data required in Clause 8.
5.1.6.2 The specimens submitted shall be deemed representative of the manufacturer's normal
production with regard to their construction and calibration. This implies that the mean response
threshold value of the 12 specimens found in the reproducibility test (5.3) should also represent the
production mean, and that the limits specified in the response threshold value test should also be
applicable to the manufacturer's production.
5.1.7 Test schedule
The specimens shall be tested according to the test schedule given in Table 1. After the reproducibility
test, number the two least sensitive specimens (i.e. those with the highest response thresholds) 12 and
13, and the others 1 to 11 arbitrarily.
Table 1 — Test schedule
Test Subclause Specimen number(s)
Repeatability 5.2 One chosen arbitrarily
Reproducibility 5.3 All specimens
a
Variation of supply parameters 5.4 1
b
Dazzling 5.5 2
Dry heat (operational) 5.6 3
Cold (operational) 5.7 4
Damp heat, steady-state (operational) 5.8 5
Damp heat, steady-state (endurance) 5.9 6
Sulfur dioxide, SO , corrosion (endurance) 5.10 7
Shock (operational) 5.11 8
Impact (operational) 5.12 9
Vibration, sinusoidal (operational) 5.13 10
Vibration, sinusoidal (endurance) 5.14 10
c
Air leakage 5.15 7, 10
Electromagnetic compatibility (EMC), Immunity tests (operational) 5.16 11
Fire sensitivity 5.17 12, 13
a
This test duplicates a test undertaken as part of the assessment of point type smoke detectors for conformance to
ISO 7240-7. Where the SDED includes a smoke detector conforming to ISO 7240-7 and does not include any additional active
electronic components, this test may be omitted.
b
This test only applies to detectors using scattered or transmitted light principle of operation. Where the SDED includes
a smoke detector conforming to ISO 7240-7 or the sensing element is mounted within an opaque enclosure, this test may be
omitted.
c
Air leakage test is undertaken after the corrosion test and the vibration tests.
5.1.8 Test report
The test results shall be reported in accordance with Clause 6.
5.2 Repeatability
5.2.1 Object of test
To show that the SDED has stable behaviour with respect to its sensitivity even after a number of alarm
conditions.
5.2.2 Test procedure
5.2.2.1 Mount the specimen to be tested as specified in 5.1.2 and connect to the supply and monitoring
equipment specified in 5.1.3.
6 © ISO 2017 – All rights reserved

5.2.2.2 Measure the response threshold value of the specimen to be tested six times for each air
velocity as specified in 5.1.5.
5.2.2.3 Designate the maximum response threshold value as y or m for each air velocity, the
max max
minimum value as y or m for each air velocity.
min min
5.2.3 Requirements
5.2.3.1 The ratio of the response threshold values, y : y or m : m , shall not be greater
max min max min
than 1,6 for each air velocity.
5.2.3.2 The lower response threshold value, y , shall not be less than 0,2, or m shall not be less
min min
than 0,05 dB/m.
5.3 Reproducibility
5.3.1 Object of test
To show that the sensitivity of the SDED does not vary unduly from specimen to specimen and to
establish response threshold value data for comparison with the response threshold values measured
after the environmental tests.
5.3.2 Test procedure
5.3.2.1 Mount the specimen to be tested as specified in 5.1.2 and connect to the supply and monitoring
equipment specified in 5.1.3.
5.3.2.2 Measure the response threshold value of each of the test specimens for each air velocity as
specified in 5.1.5.
5.3.2.3 Calculate the mean of these response threshold values for each air velocity, which shall be
designated as y or m .
5.3.2.4 Designate the maximum response threshold value as y or m and the minimum value as
max max
y or m for each air velocity.
min min
5.3.3 Requirements
5.3.3.1 The ratio of the response threshold values, y : y or m : m , shall not be greater than 1,33
max max
for each air velocity, and the ratio of the response threshold values, y : y or m : m , shall not be
min min
greater than 1,5 for each air velocity.
5.3.3.2 The lower response threshold value, y , shall not be less than 0,2, or m shall not be less
min min
than 0,05 dB/m.
5.4 Variation in supply parameters
5.4.1 Object of test
To show that, within the specified range(s) of the supply parameters (e.g. voltage), the sensitivity of the
SDED is not unduly dependent on these parameters.
5.4.2 Test procedure
5.4.2.1 Mount the specimen to be tested as specified in 5.1.2 and connect to the supply and monitoring
equipment specified in 5.1.3.
5.4.2.2 At the mean air velocity specified in 5.1.5, measure the response threshold value of the
specimen as specified in 5.1.5, at the upper and lower limits of the supply parameter (e.g. voltage)
range(s) specified by the manufacturer.
5.4.2.3 Designate the greater of the response threshold value as y or m the lesser as y
max max and min
or m .
min
NOTE For non-addressable detectors, the supply parameter is the DC voltage applied to the detector. For
other types of detector (e.g. analogue addressable), it can be necessary to consider signal levels and timing.
If necessary, the manufacturer can be requested to provide suitable supply equipment to allow the supply
parameters to be changed as required.
5.4.3 Requirements
5.4.3.1 The ratio of the response threshold values, y : y or m : m , shall not be greater
max min max min
than 1,6.
5.4.3.2 The lower response threshold value, y , shall not be less than 0,2, or m shall not be less
min min
than 0,05 dB/m.
5.5 Dazzling
5.5.1 Object of test
To show that the sensitivity of the SDED is not unduly influenced by the close proximity of artificial
light sources. This test is applied only to SDED with detectors using scattered light or transmitted light,
as detectors using ionization are considered unlikely to be influenced.
5.5.2 Test procedure
5.5.2.1 Mount the specimen as specified in 5.1.2 and connect it to supply and monitoring equipment as
specified in 5.1.3. Install the dazzling apparatus (specified in Annex D) over the portion of the specimen
mounted outside the duct, such that the smoke-sensing element and housing are fully enclosed by the
apparatus. Perform the following procedure at the mean air velocity specified in 5.1.5.
a) Measure the response threshold value as specified in 5.1.5.
b) Switch the five lamps ON simultaneously for 10 s and then OFF for 10 s. Repeat this for 10 times.
c) Switch the five lamps ON again and, after at least 1 min, measure the response threshold value as
specified in 5.1.5, with the lamps ON.
d) Switch the five lamps OFF.
5.5.2.2 Designate the maximum response threshold value as m and the minimum response
max
threshold value as m .
min
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5.5.3 Requirements
5.5.3.1 During the pe
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