ISO 7240-7:2023

Fire detection and alarm systems — Part 7: Point-type smoke detectors using scattered light, transmitted light or ionization

This document specifies requirements, test methods and performance criteria for point-type smoke detectors that operate using scattered light, transmitted light or ionization, for use in fire detection and alarm systems installed in buildings (see ISO 7240-1). This document also covers point-type smoke detectors that incorporate more than one smoke sensor operating on these principles. Additional requirements and test methods for such detectors are given in Annex N. For the testing of other types of smoke detectors, or smoke detectors working on different principles, this document is only intended to be used for guidance. This document is not applicable to smoke detectors with special characteristics, developed for specific risks. NOTE Certain types of detectors contain radioactive materials.

Systèmes de détection et d'alarme d'incendie — Partie 7: Détecteurs de fumée ponctuels utilisant le principe de la diffusion de la lumière, de la transmission de la lumière ou de l'ionisation

General Information

• Status: Published
• Publication Date: 13-Jul-2023
• 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/WG 6 - Smoke detectors
• Current Stage: 6060 - International Standard published
• Start Date: 14-Jul-2023
• Due Date: 30-Oct-2022
• Completion Date: 14-Jul-2023

Relations

• Revises: ISO 7240-7:2018 - Fire detection and alarm systems — Part 7: Point-type smoke detectors using scattered light, transmitted light or ionization
• Effective Date: 23-Apr-2020

Overview - ISO 7240-7:2023 (Point‑type smoke detectors)

ISO 7240-7:2023 is the fourth edition standard for point-type smoke detectors using scattered light, transmitted light or ionization. It specifies requirements, test methods and performance criteria for these detectors when used in building fire detection and alarm systems (see ISO 7240-1 for general system requirements). The standard also addresses multi‑sensor point detectors that combine two or more of the listed detection principles (additional requirements in Annex N). ISO 7240-7:2023 is intended for conventional building applications and is not applicable to detectors with special characteristics developed for specific risks. Note: some ionization detectors contain radioactive materials.

Key technical topics and requirements

• Scope & conformance: Defines applicability, relationship to ISO 7240-1 and the limits of use (guidance only for other detector types).
• Response thresholds: Measurement and specification of detector response for scattered‑light and transmitted‑light types.
• Individual alarm indication & ancillary connections: Requirements for alarm signalling, monitoring detachable detectors and connecting ancillary devices.
• Software requirements: Design, control and storage requirements for software‑controlled detectors.
• Environmental and mechanical tests: Operational and endurance tests including dry heat, cold, damp heat, SO2 corrosion, shock, impact, vibration and EMC immunity.
• Functional performance tests: Repeatability, reproducibility, directional dependence, supply variation, air movement effects, dazzling and fire sensitivity.
• Open vs closed detectors: Additional tests and ingress‑protection considerations for open‑type designs.
• Test procedures & reporting: Detailed test arrangements, atmospheric/operating conditions, tolerances and required test reports.

Practical applications - who uses ISO 7240-7

• Manufacturers: product design, type testing, product verification and CE/market compliance for point‑type smoke detectors.
• Test laboratories and certification bodies: apply standardized test methods and performance criteria for certification and type approval.
• Fire safety engineers & consultants: select appropriate detector technologies, assess performance under environmental conditions and specify detectors in building projects.
• Installers & system integrators: ensure correct detector selection, mounting and commissioning consistent with performance requirements.
• Building owners / procurement teams: evaluate product claims and ensure purchased detectors meet standardized performance and safety criteria.

Related standards

• ISO 7240-1 - general requirements for fire detection and alarm systems (referenced by ISO 7240-7).
• Other parts of the ISO 7240 series cover different detector types and system components.

Keywords: ISO 7240-7, point-type smoke detectors, scattered light, transmitted light, ionization, fire detection and alarm systems, smoke detector testing, performance criteria, EMC immunity.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7240-7
Fourth edition
2023-07
Fire detection and alarm systems —
Part 7:
Point-type smoke detectors using
scattered light, transmitted light or
ionization
Systèmes de détection et d'alarme d'incendie —
Partie 7: Détecteurs de fumée ponctuels utilisant le principe de
la diffusion de la lumière, de la transmission de la lumière ou de
l'ionisation
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword . vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 3
4.1 Conformance . 3
4.2 Response threshold value of detectors using scattered or transmitted light . 3
4.3 Individual alarm indication . 3
4.4 Connection of ancillary devices. 3
4.5 Monitoring of detachable detectors . 3
4.6 Manufacturer's adjustments . 4
4.7 On-site adjustment of response behaviour . 4
4.8 Protection against the ingress of foreign bodies . 4
4.8.1 Closed detectors . 4
4.8.2 Open detectors . 4
4.9 Response to slowly developing fires . 4
4.10 Requirements for software-controlled detectors . 5
4.10.1 General . 5
4.10.2 Software design . 5
4.10.3 Storage of programs and data . 5
5 Tests . 5
5.1 General . 5
5.1.1 Atmospheric conditions for tests. 5
5.1.2 Operating conditions for tests. 5
5.1.3 Mounting arrangements . 6
5.1.4 Tolerances . 6
5.1.5 Measurement of response threshold value . 6
5.1.6 Provision for tests . 7
5.1.7 Test schedule . 7
5.1.8 Test report . 8
5.2 Repeatability . 8
5.2.1 Object of test. 8
5.2.2 Test procedure. 8
5.2.3 Requirements . 8
5.3 Directional dependence . 8
5.3.1 Object of test. 8
5.3.2 Test procedure. 8
5.3.3 Requirements . 9
5.4 Reproducibility . 9
5.4.1 Object of test. 9
5.4.2 Test procedure. 9
5.4.3 Requirements . 9
5.5 Variation in supply parameters . 9
5.5.1 Object of test. 9
5.5.2 Test procedure. 9
5.5.3 Requirements . 10
5.6 Air movement . 10
5.6.1 Object of test. 10
5.6.2 Test procedure. 10
5.6.3 Requirements . 10
5.7 Dazzling . 11
iii
5.7.1 Object of test. 11
5.7.2 Test procedure. 11
5.7.3 Requirements . 11
5.8 Additional tests for open detectors . 11
5.8.1 Object of the test . 11
5.8.2 Test procedure. 11
5.9 Dry heat (operational) . 12
5.9.1 Object of test. 12
5.9.2 Test procedure.12
5.9.3 Requirements .12
5.10 Cold (operational) . 13
5.10.1 Object of test. 13
5.10.2 Test procedure. 13
5.10.3 Requirements .13
5.11 Damp heat, steady state (operational) . 13
5.11.1 Object of test. 13
5.11.2 Test procedure. 14
5.11.3 Requirements . 14
5.12 Damp heat, steady state (endurance) . 14
5.12.1 Object of test. 14
5.12.2 Test procedure. 14
5.12.3 Requirements .15
5.13 Sulfur dioxide (SO ) corrosion (endurance) . 15
5.13.1 Object of test. 15
5.13.2 Test procedure. 15
5.13.3 Requirements . 16
5.14 Shock (operational) . 16
5.14.1 Object of test. 16
5.14.2 Test procedure. 16
5.14.3 Requirements . 17
5.15 Impact (operational) . 17
5.15.1 Object of test. 17
5.15.2 Test procedure. 17
5.15.3 Requirements . 18
5.16 Vibration, sinusoidal, (operational) . 18
5.16.1 Object of test. 18
5.16.2 Test procedure. 18
5.16.3 Requirements . 19
5.17 Vibration, sinusoidal (endurance) . 19
5.17.1 Object of test. 19
5.17.2 Test procedure. 19
5.17.3 Requirements .20
5.18 Electromagnetic compatibility (EMC) immunity tests (operational) . 20
5.19 Fire sensitivity . 20
5.19.1 Object of test. 20
5.19.2 Test procedure.20
5.19.3 Requirements .22
6 Test report .22
7 Marking . .22
8 Data .23
8.1 Hardware documentation .23
8.2 Software documentation .23
Annex A (normative) Smoke tunnel for response threshold value measurements .25
Annex B (normative) Test aerosol for response threshold value measurements .26
Annex C (normative) Smoke-measuring instruments .27
iv
Annex D (normative) Apparatus for dazzling test .31
Annex E (normative) Apparatus for impact test .32
Annex F (normative) Fire test room . .34
Annex G (normative) Smouldering (pyrolysis) wood fire (TF2) .36
Annex H (normative) Glowing smouldering cotton fire (TF3) .39
Annex I (normative) Flaming plastics (polyurethane) fire (TF4) .42
Annex J (normative) Flaming liquid (n-heptane) fire (TF5) .45
Annex K (informative) Information concerning the construction of the smoke tunnel .48
Annex L (informative) Compensation for detector drift .50
Annex M (informative) Information concerning the construction of the measuring
ionization chamber .54
Annex N (normative) Apparatus for open detector static object test .56
Annex O (normative) Apparatus for testing the protection against the effect of moving
objects .57
Bibliography .59
v
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
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 21, Equipment for fire protection and fire
fighting, Subcommittee SC 3, Fire detection and alarm systems.
This fourth edition cancels and replaces the third edition (ISO 7240-7: 2018), which has been technically
revised.
The main changes are as follows:
— a simplification of the use of the threshold values of Band 1 and Band 2, previously introduced in
the third edition. The intention of this change is to improve the readability of the document by
removing unnecessary repetition.
— various editorial modifications to bring the document in line with current editorial rules.
A list of all parts in the ISO 7240 series can be found on the ISO website.
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.
vi
Introduction
A fire detection and alarm system is required to function satisfactorily not only in the event of fire, but
also during and after exposure to conditions likely to be met in practice, including corrosion, vibration,
direct impact, indirect shock and electromagnetic interference. Specific tests are intended to assess the
performance of the smoke detectors under such conditions.
This document is not intended to place any other restrictions on the design and construction of such
detectors.
This edition of this document introduces a requirement that smoke detectors that operate on the
scattered or transmitted light principle be marked with one of two possible nominal response threshold
value bands. This marking provides for a clearer choice of response values, enabling a decrease in the
risk of unwanted alarms in installations where unfavourable environmental conditions are present.
NOTE For some test fires, smoke detectors that operate on the scattered or transmitted light principle and
that have been factory set to the upper response threshold value band can fall outside one of the classification
limits given in ISO/TR 7240-9.
vii
INTERNATIONAL STANDARD ISO 7240-7:2023(E)
Fire detection and alarm systems —
Part 7:
Point-type smoke detectors using scattered light,
transmitted light or ionization
1 Scope
This document specifies requirements, test methods and performance criteria for point-type smoke
detectors that operate using scattered light, transmitted light or ionization, for use in fire detection
and alarm systems installed in buildings (see ISO 7240-1). This document also covers point-type smoke
detectors that incorporate more than one smoke sensor operating on these principles. Additional
requirements and test methods for such detectors are given in Annex N.
For the testing of other types of smoke detectors, or smoke detectors working on different principles,
this document is only intended to be used for guidance. This document is not applicable to smoke
detectors with special characteristics, developed for specific risks.
NOTE Certain types of detectors contain radioactive materials.
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
IEC 60068-1, Environmental testing — Part 1: General and guidance
IEC 60068-2-1, Environmental testing — Part 2-1: Tests — Test A: Cold
IEC 60068-2-2, Environmental testing — Part 2-2: Tests — Tests B: Dry heat
IEC 60068-2-6, Environmental testing — Part 2-6: Tests — Test Fc: Vibration (sinusoidal)
IEC 60068-2-27, Environmental testing — Part 2-27: Tests — Test Ea and guidance: Shock
IEC 60068-2-42, Environmental testing — Part 2-42: Tests — Test Kc: Sulphur dioxide test 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 terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
aerosol density
smoke density
amount of particulates per volume as described operationally by one of two parameters:
— m (3.3), an absorbance index, used in the testing of smoke detectors using scattered or transmitted
light; or
— y (3.7), a dimensionless variable, used in the testing of smoke detectors using ionization
Note 1 to entry: Strictly speaking, these parameters are not concentrations, but rather they represent values
which are proportional to the concentration and have been shown to function in place of a true concentration
value for the purposes of these tests.
3.2
least sensitive orientation
point of rotation, relative to air flow, about the vertical axis where a detector produces the maximum
response threshold value
3.3
absorbance index
m
measured light attenuation characterizing the concentration of particulates in smoke or an aerosol
Note 1 to entry: The formula for m in Annex C applies.
3.4
closed detector
optical or ionization smoke detector with the sensing volume(s) inside the enclosure
Note 1 to entry: Smoke needs to enter the detector’s enclosure to be detected.
3.5
open detector
optical smoke detector with the sensing volume(s) outside the enclosure
Note 1 to entry: Smoke is detected outside the detector’s enclosure.
3.6
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 can depend on signal processing in the detector and in the control
and indicating equipment.
3.7
y
dimensionless variable, reflecting the change in the current flowing in an ionization chamber as a
known function of the concentration of particulates in the smoke or aerosol
Note 1 to entry: The formula for y in Annex C applies.
4 General requirements
4.1 Conformance
In order to conform to the provisions of this document, the detector shall meet the requirements of:
a) Clause 4, which shall be verified by visual inspection or engineering assessment;
b) the tests as described in Clause 5;
c) Clauses 7 and 8, which shall be verified by visual inspection.
4.2 Response threshold value of detectors using scattered or transmitted light
Detectors using scattered or transmitted light shall conform to one of the two response threshold value
bands specified in Table 1 and the corresponding end-of-test conditions for the test fires specified in
5.18.
Table 1 — Response threshold value for detectors using scattered or transmitted light
Band Response threshold value lower Test fires (TF) end-of-test conditions
limit in smoke tunnel (aerosol)
TF2 TF3 TF4 TF5
dB/m dB/m dimensionless dimensionless
dB/m
1 0,05 m = 2 m = 2 y = 6 y = 6
2 0,2 m = 2 m = 2 y = 6,5 y = 7,5
NOTE The smaller the m value, the higher the sensitivity of the detectors.
4.3 Individual alarm indication
Each detector shall be provided with an integral red visual indicator by which the individual detector
releasing an alarm can be identified, until the alarm condition is reset. Where other conditions of the
detector may be visually indicated, these shall be clearly distinguishable from the alarm indication,
except when the detector is switched into a service mode. For detachable detectors, the indicator may
be integral with the base or the detector head.
NOTE The alarm condition is reset manually at the control and indicating equipment (see ISO 7240-2).
The visual indicator shall be visible from a distance of 6 m in an ambient light intensity of 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.
4.4 Connection of ancillary devices
The detector 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
detector.
4.5 Monitoring of detachable detectors
For detachable detectors, a means shall be provided for a remote monitoring system (e.g. the control
and indicating equipment) to detect the removal of the head from the base, in order to give a fault signal.
4.6 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.
4.7 On-site adjustment of response behaviour
If there is provision for on-site adjustment of the response behaviour of the detector, then:
a) for all of the settings at which the manufacturer claims conformance, the detector shall conform
to 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 detector from its base or mounting;
b) any setting or settings at which the manufacturer does not claim conformance to this document
shall be accessible only by the use of a code or special tool, and it shall be clearly marked on the
detector or in the associated data that if this setting or settings are used, the detector does not
conform to this document.
These adjustments may be carried out at the detector or at the control and indicating equipment.
4.8 Protection against the ingress of foreign bodies
4.8.1 Closed detectors
Closed detectors shall be designed so that a sphere of diameter (1,3 ± 0,05) mm cannot pass into the
sensor chamber(s).
NOTE This requirement is intended to restrict the access of insects into the sensitive parts of the detector. It
is known that this requirement is not sufficient to prevent the access of all insects. However, it is considered that
extreme restrictions on the size of access holes can introduce the danger of clogging by dust, etc. It can therefore
be necessary to take other precautions against false alarms due to the entry of small insects.
4.8.2 Open detectors
The open detector shall be designed such that:
a) a sphere of (1,3 ± 0,05) mm diameter cannot pass into any enclosure containing active optoelectronic
components;
b) a total block of the detector surface shall not cause an alarm but shall signal a fault;
c) an object moving with a minimum distance of (6 ± 1) mm to the nearest point of the surface of the
detector shall not cause an alarm but shall signal a fault.
4.9 Response to slowly developing fires
The provision of “drift compensation” (e.g. to compensate for sensor drift due to the build-up of dirt
in the detector), shall not lead to a significant reduction in the sensitivity of the detector to slowly
developing fires (see Annex L).
Since it is not practical to make tests with very slow increases in smoke density, an assessment of the
response of the detector to slow increases in smoke density shall be made by analysis of the circuit/
software, and/or physical tests and simulations.
The detector shall be deemed to meet the requirements of this clause if this assessment shows the
following:
a) that for any rate of increase in smoke density, R, which is greater than 25 % of the initial
uncompensated response threshold value of the detector, A , per hour, the time for the detector
th,u
to give an alarm does not exceed 1,6 × (A :R) by more than 100 s;
th,u
b) that the total compensation, C , is limited such that C < 0,6 A throughout this range, and that the
t t th,u
fully compensated response threshold value, A , does not exceed its initial value A by a factor
th,c th,u
greater than 1,6.
4.10 Requirements for software-controlled detectors
4.10.1 General
The requirements of 4.10.2 and 4.10.3 shall be met for detectors which rely on software control in order
to fulfil the requirements of this document.
4.10.2 Software design
In order to ensure the reliability of the detector, the following requirements for software design 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.
4.10.3 Storage of programs and data
The program necessary to conform to 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.
Site-specific data shall be held in memory which retains data for at least two weeks without external
power to the detector, 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, carry out the testing after the test specimen has been
allowed to stabilize in the standard atmospheric conditions for testing as specified 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 Operating conditions for tests
If a test method requires a specimen to be operational, then connect the specimen to suitable supply
and monitoring equipment having the characteristics 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 conventional detectors) to allow a fault signal to be recognized.
The details of the supply and monitoring equipment and the alarm criteria used shall be given in the
test report (Clause 6).
5.1.3 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 choose the method
considered to be most unfavourable for each test.
5.1.4 Tolerances
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).
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 Measurement of response threshold value
Install the specimen for which the response threshold value, A , is to be measured in the smoke tunnel,
th
as described in Annex A, in its normal operating position, by its normal means of attachment. The
orientation of the specimen, relative to the direction of air flow, shall be the least sensitive orientation,
as determined in the directional dependence test, unless otherwise specified in the test procedure.
Before commencing each measurement, purge the smoke tunnel to ensure that the tunnel and the
specimen are free from the test aerosol.
The air velocity in the proximity of the specimen shall be (0,2 ± 0,04) m/s during the measurement,
unless otherwise specified in the test procedure.
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 °C for all the measurements on a particular detector type.
Connect the specimen to its supply and monitoring equipment as specified in 5.1.2, and allow it to
stabilize for a period of at least 15 min, unless otherwise specified by the manufacturer.
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 detectors using scattered or transmitted light, in dB/m/min:
Δm
0,,015≤≤01 ;
Δt
Δy
— for detectors using ionization, per min: 00,,50≤≤ 3 .
Δt
NOTE These ranges are intended to allow the selection of a convenient rate, depending on the sensitivity of
the detector, so that a response can be obtained in a reasonable time.
The rate of increase initially selected in aerosol density shall be similar for all measurements on a
particular detector type.
The response threshold value is the aerosol density (m or y) at the moment that the specimen gives an
alarm. This shall be recorded as m, expressed in dB/m for detectors using scattered or transmitted
light, or as y for detectors using ionization (see Annex C).
5.1.6 Provision for tests
Provide the following for testing conformance with this document:
a) for detachable detectors, 20 detector heads and bases; for non-detachable detectors, 20 specimens;
b) the data specified in 8.1.
NOTE Detachable detectors comprise at least two parts: a base (socket) and a head (body). If the s
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