ISO/PRF 16840-10

• Abstract:

  This document specifies requirements and test methods to assess the resistance to ignition by smouldering cigarette equivalent of integrated or non-integrated components of a wheelchair intended to protect tissue integrity and/or provide postural support. The electronic ignition source is also a simulation of other potential sources of environmental ignition hazards. The tests measure only the resistance to ignition of the items tested, and not the ignitability of the complete wheelchair. It gives an indication, but cannot guarantee, the ignition behaviour of the assembled devices of a complete wheelchair. This document does not apply to resistance to ignition of structural parts of a wheelchair. This document does not cover changes in resistance to ignition as a result of regular washing or use of the postural support devices. This document does not apply to the control of risks created by electrical and electronic components. This document allows for the separate testing of components of a wheelchair that are normally used in the horizontal plane (e.g. a seat cushion) from those normally used in the vertical plane (e.g. a back support). This document describes testing an assembly of the composite of materials as used in the component. The results of the tests in this document do not give any indication of the resistance to ignition of any of the separate individual materials of the test sample. NOTE The intent of this document is primarily to address components that interface with the human body, such as cushions for positioning, or whose described purpose is that of protecting skin tissue against pressure, shear, and maceration related damage, as well as textile, foam, and plastic-based postural support devices.

• Status: Not Published
• ICS: 11.180.10 - Aids and adaptation for moving
• Technical Committee: ISO/TC 173/SC 1 - Wheelchairs
• Drafting Committee: ISO/TC 173/SC 1/WG 11 - Wheelchair seating
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 21-Sep-2026
• Completion Date: 26-Sep-2026

• Revises: ISO 16840-10:2021 - Wheelchair seating — Part 10: Resistance to ignition of postural support devices — Requirements and test method
• Effective Date: 07-Dec-2025
• Revises: ISO 16840-10:2021/Amd 1:2024 - Wheelchair seating — Part 10: Resistance to ignition of postural support devices — Requirements and test method — Amendment 1: Amended with additional Annexes and test method
• Effective Date: 07-Dec-2025

Overview

ISO/PRF 16840-10 is an ISO standard for wheelchair seating that defines the requirements and test method for assessing resistance to ignition of postural support devices (PSDs). It is designed for integrated and non-integrated wheelchair components that help protect tissue integrity or provide postural support.

This standard is especially relevant for products such as:

• Seat cushions
• Back supports
• Lateral supports
• Head supports
• Pelvic positioning belts
• Anterior trunk supports
• Textile, foam, and plastic-based seating components

The document focuses on a smouldering cigarette equivalent heat source and a reproducible test method intended to reflect ignition hazards in real-world wheelchair use. It measures the resistance to ignition of the tested item, not the full wheelchair assembly.

Key Topics

Ignition resistance testing

ISO/PRF 16840-10 specifies a practical method to evaluate whether postural support devices resist ignition when exposed to a standardised heat source. The test can be carried out in both:

• Horizontal orientation for items such as seat cushions
• Vertical orientation for items such as back supports

For smaller PSDs, the method identifies how to apply the heat source to the most exposed area.

Scope and limitations

The standard is important because it clarifies what the test does and does not cover:

• It applies to PSD surfaces and composites, not separate raw materials
• It does not assess the ignitability of the complete wheelchair
• It does not address structural wheelchair parts
• It does not cover changes caused by washing or routine use
• It does not replace controls for electrical or electronic fire risks

Test method and reporting

The test uses a hot wire coil calibrated to reproduce the thermal effect and burn pattern of a cigarette equivalent. The procedure includes:

• Sample preparation and conditioning
• Heat source calibration
• Defined test orientations
• Observation for flaming and smouldering
• A structured test report with documented results and deviations

Applications

ISO/PRF 16840-10 supports manufacturers, laboratories, purchasers, and specifiers involved in wheelchair seating fire safety. It is useful for:

• Product design and development
• Procurement and specification of wheelchair seating
• Conformity assessment and laboratory testing
• Risk management for assistive products
• Selection of safer materials for human-body-contact components

The standard helps organizations make informed decisions about flammability performance, especially for products intended to reduce pressure, shear, and maceration-related tissue damage while maintaining comfort and support.

Related Standards

Several ISO standards are referenced or closely connected to ISO/PRF 16840-10:

• ISO 7176-26 - Wheelchair vocabulary
• ISO 8191-1 - Ignitability of upholstered furniture using a smouldering cigarette ignition source
• ISO 7176-14 - Requirements for the control of fire risks from electrical and electronic components
• ISO 10993-1 - Biological evaluation and biocompatibility risk management
• ISO 14971 - Risk management for medical devices

Together, these standards help support a more complete approach to wheelchair safety, material selection, and ignition resistance testing.

International
Standard
ISO 16840-10
Third edition
Wheelchair seating —
Part 10:
Requirements and test method for
the assessment of resistance to
ignition of postural support devices
PROOF/ÉPREUVE
Reference number
ISO 16840-10:2026(en) © ISO 2026

ISO 16840-10:2026(en)
© ISO 2026
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
PROOF/ÉPREUVE
ii
ISO 16840-10:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Health and safety of test personnel . 2
5.1 General .2
5.2 Enclosure .2
5.3 Extinguishers .3
6 Apparatus . 3
6.1 Test enclosure .3
6.2 Timer .3
6.3 Heat source .3
6.3.1 General .3
6.3.2 Wire coil .3
6.3.3 Power supply and connection to wire coil.4
6.3.4 Conditioning the wire coil .4
6.3.5 Paper calibration strip .4
6.4 Test environment .5
6.5 Test sample .5
7 Test procedure . 5
7.1 Sample preparation .5
7.2 Sample conditioning .5
7.3 Selection of testing orientation .5
7.4 Heat source calibration .5
7.5 Wire coil cleaning between tests .6
7.6 Horizontal test .6
7.7 Vertical test.7
7.8 Smaller PSDs .8
8 Requirements . 9
9 Test report . 9
Annex A (informative) Guidance on fabrication of the test coil apparatus .11
Annex B (informative) Selection of surface(s) at risk, to be used for testing .18
Annex C (informative) Test report example . 19
Bibliography .22
PROOF/ÉPREUVE
iii
ISO 16840-10:2026(en)
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).
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 173, Assistive products, Subcommittee SC 1,
Wheelchairs.
This third edition cancels and replaces the second edition (ISO 16840-10:2021) which has been technically
revised. It also incorporates the Amendment ISO 16840-10:2021/Amd. 1:2024.
The main changes are:
— removal of the original test method and incorporation of the test method from the amendment.
A list of all parts in the ISO 16840 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.
PROOF/ÉPREUVE
iv
ISO 16840-10:2026(en)
Introduction
The ignition and subsequent burning of wheelchairs is very rare, but this can occur as a result of
— being close to a burning object such as a fire beside the wheelchair,
— overheating of any electrical or electronic device on the wheelchair, and
— contact from sparks or flames (such as welding sparks, cigarettes, or matches).
Wheelchair occupants are at particular risk of injury or death from these fires and resulting fumes because
it is very possible that they do not have the ability to move away from the wheelchair.
NOTE In the United States, data collected in the 1990s showed that only a small number of individuals per
[7] st
million wheelchair users had died due to fire . Public FDA records indicate most 21 century flammability incidents
[8]
involving wheelchairs are from electrical faults .
Wheelchairs can be considered to comprise the following components:
a) structural components such as the frame, wheels, etc., that are essential to the mechanical integrity of
the wheelchair;
b) power-related components such as motors, energy sources, controllers etc., that are required for the
functioning of powered devices on wheelchairs.
c) integrated or non-integrated devices to manage tissue integrity, such as seat and back support cushions,
that are intended to have primarily a clinical function to minimize the risks of skin damage (these can
also be intended to control or accommodate posture);
d) postural support devices, including, but not limited to, sling seats, sling back supports, arm supports,
foot supports, pelvic positioning supports (hip belts), anterior trunk supports (harnesses and chest
belts), lateral pelvic/trunk supports (lateral pads) etc., that are attached to the wheelchair and are
primarily intended to give positioning and postural support to the wheelchair occupant (these can also
be intended to aid in pressure redistribution);
Each of the above components has a different severity of risk associated with its likelihood of igniting and its
resulting harm to the wheelchair occupant. This document specifies requirements and a test method to help
manufacturers and purchasers of wheelchairs to design and procure wheelchairs and their components that
are appropriate for the risk of ignition balanced against the functional needs of the wheelchair occupant.
The aim of this document is to provide appropriate alternatives to using furniture-based flammability
standards, to reflect the uses and purposes of wheelchairs and their accessories.
There is yet no International Standard on the resistance to ignition of structural components [see list item
a) above].
The power related components [see list item b) above] are the subject of ISO 7176-14 which specifies
requirements to prevent overheating in electrical components that could lead to a fire.
The tissue integrity devices [see list item c) above] and postural support devices [see list item d) above] are
the subject of this document. For this purpose, a smouldering cigarette as a standardised heat source is not
necessarily a reproducible heat source, since the heat output between cigarettes from within one pack is
variable, and between different packs even more so. Since the early furnishing flammability standards were
introduced, filter tipped and fire safe cigarettes have evolved, and thus today, testing is not being carried out
with the equivalent heat source as when the furnishing flammability standards were first drafted. The aim
of this document is to describe a reproducible standardised heat source output which reproduces the burn
pattern and potential for ignition of a cigarette.
Cross-lab validation testing has shown that the previously recommended cartridge heater did not reproduce
the burn pattern or potential for ignition of a cigarette, and it did not reliably produce the same test results
as the hot wire coil.
PROOF/ÉPREUVE
v
ISO 16840-10:2026(en)
Various existing flammability standards allow for active flaming for two-minutes after removal of the heat
source. By this time a wheelchair occupant could suffer severe injuries directly or by secondary ignition of
other materials in the environment. This current document differs in that it tests for resistance to ignition
‒ no flaming ignition is allowed. Given the full consideration of the wheelchair user’s safety and long-term
health, this document has been drafted to be used as the flammability standard for all seating textiles/soft
components of a wheelchair that interface with the human body.
Global efforts are under way to eliminate the use of chemicals which present a serious risk to humans and
the environment. Good practice is also to use biocompatible materials that minimize the risk of exposure to
the wheelchair occupant to toxic substances. Materials chosen are required to conform to biocompatibility
requirements and risk management guidance of ISO 10993-1. The change of emphasis around the materials
to be used minimises the use of toxic and hazardous flame-retardant chemicals, which is preferable due to
the minimal contribution of seating system materials to fire severity.
Materials chosen should comply with biocompatibility requirements and risk management guidance of
ISO 10993-1, which includes consideration of cytotoxicity, sensitization, and irritation evaluations for
devices making contact with intact skin.
The pass criteria within this document have been set at a basic minimal level and can differ from current
requirements in some countries. Where practical, manufacturers should use materials with superior
resistance to ignition, when the overall risk analysis indicates the benefits outweigh any unintended harm,
in accordance with ISO 14971.
The day to day usage of a wheelchair can affect its materials’ resistance to ignition through cyclic loading,
movement of materials, washing, cleaning, etc. Manufacturers will often take this effect into account as part
of their risk assessment when selecting materials for their products to minimize the effects of this normal
use. However, although this document can be used on parts that have been used, etc., the test samples
specify new or unused parts. Different environments commonly encountered by some wheelchair occupants
can also affect the flammability of materials. For example, home oxygen systems, delivery systems for drugs
carried in an inflammable medium, etc., can turn an inert material into a flammable one. Dust and other
materials accumulated within the chair have also been found to be a source of readily ignitable material.
Wheelchair manufacturers and occupants should be aware of these risks, and should design and use
wheelchairs accordingly, as covered by ISO 14971.
PROOF/ÉPREUVE
vi
International Standard ISO 16840-10:2026(en)
Wheelchair seating —
Part 10:
Requirements and test method for the assessment of
resistance to ignition of postural support devices
1 Scope
This document specifies requirements and a test method to assess the resistance to ignition by a smouldering
cigarette equivalent of integrated or non-integrated components of a wheelchair intended either to protect
tissue integrity or to provide postural support, or both. The electrical ignition source is also a simulation of
other potential sources of environmental ignition hazards.
The test measures only the resistance to ignition of the items tested, and not the ignitability of the complete
wheelchair. It gives an indication of, but cannot guarantee, the ignition behaviour of the assembled devices
of a complete wheelchair.
This document does not apply to resistance to ignition of structural parts of a wheelchair. This document
does not cover changes in resistance to ignition as a result of regular washing or use of the postural support
devices.
This document allows for the separate testing of components of a wheelchair that are normally used in the
horizontal plane (e.g. a seat cushion) from those normally used in the vertical plane (e.g. a back support).
This document describes testing an assembly of the composite of materials as used in the component. The
results of the test in this document do not give any indication of the resistance to ignition of any of the
separate individual materials of the test sample.
NOTE 1 The intent of this document is primarily to address components that interface with the human body, such
as cushions for positioning, or whose described purpose is that of protecting skin tissue against pressure, shear, and
maceration related damage, as well as textile, foam, and plastic-based postural support devices.
NOTE 2 The pass criteria within this document have been set at a basic minimal level and can differ from current
requirements in some countries.
NOTE 3 Requirements for the control of risks from sources of fire created by electrical and electronic components
are included in ISO 7176-14.
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 7176-26, Wheelchairs — Part 26: Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7176-26 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
PROOF/ÉPREUVE
ISO 16840-10:2026(en)
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
flaming
undergoing combustion in the gaseous phase with the emission of light
[SOURCE: ISO 8191-1:1987, 3.2]
3.2
non-integrated
detachable without the use of tools
Note 1 to entry: Seat or back support cushions held in place by hook and loop fastenings are also considered non-
integrated.
3.3
postural support device
PSD
structure, attached to a wheelchair, that has a surface that contacts the occupant’s body and is used either to
support, correct or stabilise the occupant’s sitting posture
EXAMPLE Seat, back support, lateral support, head support, pelvic positioning belt, anterior trunk support.
[SOURCE: ISO 7176-26:2007, 4.7.3 modified — The deprecated term “postural support” has been removed; in
the definition, “modify or accommodate” has been changed to “support, correct or stabilise”.]
3.4
smouldering
exothermic oxidation, not accompanied by flaming (3.1), that is self-propagating, i.e. without an external
ignition source
Note 1 to entry: It is possible that smouldering is accompanied by incandescence.
4 Principle
Test materials used in integrated and non-integrated seat and back supports, and other postural support
devices as used in wheelchairs are assembled in either horizontal or vertical samples and subjected to a heat
source that is equivalent to a smouldering cigarette in its thermal output and capacity to ignite materials
used in wheelchair seating. The resulting effects on the test materials are observed and measured.
NOTE The tests are repeated a second time to ensure that they are repeatable, but without incurring the costs of
more tests than needed as a minimum.
5 Health and safety of test personnel
5.1 General
WARNING — The following test requirements call for the use of procedures that can be hazardous to
health if adequate precautions are not taken.
The precautions listed in 5.2 and 5.3 are drawn from ISO 8191-1:1987, Clause 6.
Ensure that there is no hidden smouldering of the sample before disposal.
5.2 Enclosure
For safety, the tests should be conducted in a non-combustible fume cupboard. If such a cupboard is not
available, a test enclosure shall be constructed (see 6.2) so that the operator is protected from the fumes.
PROOF/ÉPREUVE
ISO 16840-10:2026(en)
5.3 Extinguishers
Adequate means of extinguishing the assembly shall be provided, bearing in mind that some product
combinations can produce severe flaming during the test.
NOTE A hand and/or a fixed water spray that can be directed over the burning area can be useful. Other means
such as fire extinguishers (water and halogenated hydrocarbons), fire blankets, and a bucket of water will assist in
extin
...

ISO/DISPRF 16840-10:2026(en)
ISO/TC 173/SC 01/WG 11 1
Secretariat: SABS
Date: 2026-06-0109-21
Wheelchair seating — —
Part 10:
Requirements and test method for the assessment of resistance to
ignition of postural support devices
PROOF
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: + 41 22 749 01 11
Fax: [phone]
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO/DISPRF 16840-10:2026(en)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
5 Health and safety of test personnel . 3
5.1 General . 3
5.2 Enclosure . 3
5.3 Extinguishers . 3
6 Apparatus . 3
6.1 Test enclosure . 3
6.2 Timer . 3
6.3 Heat source. 3
6.4 Test environment . 5
6.5 Test sample . 6
7 Test procedure . 6
7.1 Sample preparation . 6
7.2 Sample conditioning . 6
7.3 Selection of testing orientation . 6
7.4 Heat source calibration . 6
7.5 Wire coil cleaning between tests . 7
7.6 Horizontal test . 8
7.7 Vertical test . 10
7.8 Smaller PSDs . 12
8 Requirements . 13
9 Test report . 13
Annex A (informative) Guidance on fabrication of the test coil apparatus . 15
Annex B (informative) Selection of surface(s) at risk, to be used for testing. 27
Annex C (informative) Test report example . 28
Bibliography . 35

iii
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).
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 173, Assistive products, Subcommittee
SC01SC 1, Wheelchairs.
This third edition cancels and replaces the second edition (ISO 16840-10:2021) which has been technically
revised. ,.It also incorporates the Amendment ISO 16840-10:2021/Amd. 1:2024.
The main changes are theremoval:
— removal of the original test method and the incorporation of the test method from ISO 16840-10-
:2021/Amd. 1:2024the amendment.
—
A list of all parts in the ISO 16840 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.
iv
ISO/DISPRF 16840-10:2026(en)
Introduction
The ignition and subsequent burning of wheelchairs is very rare, but this can occur as a result of
— — being close to a burning object such as a fire beside the wheelchair,
— — overheating of any electrical or electronic device on the wheelchair, and
— — contact from sparks or flames (such as welding sparks, cigarettes, or matches).
Wheelchair occupants are at particular risk of injury or death from these fires and resulting fumes because it
is very possible that they do not have the ability to move away from the wheelchair.
NOTE In the United States, data collected in the 1990s showed that only a small number of individuals per million
[7] [4] st
wheelchair users had died due to fire . . Public FDA records indicate most 21 century flammability incidents involving
[8][5]
wheelchairs are from electrical faults .
Wheelchairs can be considered to comprise the following components:
a) a) structural components such as the frame, wheels, etc., that are essential to the mechanical
integrity of the wheelchair;
b) b) power-related components such as motors, energy sources, controllers etc., that are required
for the functioning of powered devices on wheelchairs.
c) c) integrated or non-integrated devices to manage tissue integrity, such as seat and back support
cushions, that are intended to have primarily a clinical function to minimize the risks of skin damage
(these can also be intended to control or accommodate posture);
d) d) postural support devices, including, but not limited to, sling seats, sling back supports, arm
supports, foot supports, pelvic positioning supports (hip belts), anterior trunk supports (harnesses and
chest belts), lateral pelvic/trunk supports (lateral pads) etc., that are attached to the wheelchair and are
primarily intended to give positioning and postural support to the wheelchair occupant (these can also
be intended to aid in pressure redistribution);
Each of the above components has a different severity of risk associated with its likelihood of igniting and its
resulting harm to the wheelchair occupant. This document specifies requirements and a test methodsmethod
to help manufacturers and purchasers of wheelchairs to design and procure wheelchairs and their
components that are appropriate for the risk of ignition balanced against the functional needs of the
wheelchair occupant. The aim of this document is to provide appropriate alternatives to using furniture-based
flammability standards, to reflect the uses and purposes of wheelchairs and their accessories.
There is yet no International Standard on the resistance to ignition of structural components [see list item a)
above]].
The power related components [see list item b) above] are the subject of ISO 7176–-14 which specifies
requirements to prevent overheating in electrical components that could lead to a fire.
The tissue integrity devices [see list item c) above] and postural support devices [see list item d) above] are
the subject of this document. For this purpose, using a smouldering cigarette as a standardised heat source is
not necessarily a reproducible heat source, since the heat output between cigarettes from within one pack is
variable, and between different packs even more so. Since the early furnishing flammability standards were
introduced, filter tipped and fire safe cigarettes have evolved, and thus today, testing is not being carried out
with the equivalent heat source as when the furnishing flammability standards were first drafted. The aim of
v
this document is to describe a reproducible standardised heat source outputwhichoutput which reproduces
the burn pattern and potential for ignition of a cigarette.
Cross-lab validation testing has shown that the previously recommended cartridge heater did not reproduce
the burn pattern or potential for ignition of a cigarette, and it did not reliably produce the same test results as
the hot wire coil.
Various existing flammability standards allow for active flaming for two-minutes after removal of the heat
source. By this time a wheelchair occupant could suffer severe injuries directly or by secondary ignition of
other materials in the environment. This current document differs in that it tests for resistance to ignition —
‒ no flaming ignition is allowed. Given the full consideration of the wheelchair user’s safety and long-term
health, this document has been drafted to be used as the flammability standard for all seating textiles/soft
components of a wheelchair that interface with the human body.
Global efforts are under way to eliminate the use of chemicals which present a serious risk to humans and the
environment. Good practice is also to use biocompatible materials that minimize the risk of exposure to the
wheelchair occupant to toxic substances. Materials chosen are required to conform to biocompatibility
requirements and risk management guidance of ISO 10993-1. The change of emphasis around the materials
to be used minimises the use of toxic and hazardous flame-retardant chemicals, which is preferable due to the
minimal contribution of seating system materials to fire severity.
Materials chosen should comply with biocompatibility requirements and risk management guidance of
ISO 10993–-1, which includes consideration of cytotoxicity, sensitization, and irritation evaluations for
devices making contact with intact skin.
The pass criteria within this document have been set at a basic minimal level and can differ from current
requirements in some countries. Where practical, manufacturers should use materials with superior
resistance to ignition, when the overall risk analysis indicates the benefits outweigh any unintended harm, in
accordance with ISO 14971.
The day to day usage of a wheelchair can affect its materials’ resistance to ignition through cyclic loading,
movement of materials, washing, cleaning, etc. Manufacturers will often take this effect into account as part of
their risk assessment when selecting materials for their products to minimize the effects of this normal use.
However, although this document can be used on parts that have been used, etc., the test samples specify new
or unused parts. Different environments commonly encountered by some wheelchair occupants can also affect
the flammability of materials. For example, home oxygen systems, delivery systems for drugs carried in an
inflammable medium, etc., can turn an inert material into a flammable one. Dust and other materials
accumulated within the chair have also been found to be a source of readily ignitable material. Wheelchair
manufacturers and occupants should be aware of these risks, and should design and use wheelchairs
accordingly, as covered by ISO 14971.
vi
DRAFT International Standard ISO/DIS 16840-10:2026(en)

Wheelchair Seating — seating —
Part 10:
Requirements and test method for the assessment of resistance to
ignition of postural support devices
1 Scope
This document specifies requirements and a test method to assess the resistance to ignition by a smouldering
cigarette equivalent of integrated or non-integrated components of a wheelchair intended either to protect
tissue integrity or to provide postural support.,, or both. The electrical ignition source is also a simulation of
other potential sources of environmental ignition hazards.
The tests measuretest measures only the resistance to ignition of the items tested, and not the ignitability of
the complete wheelchair. It gives an indication of, but cannot guarantee, of the ignition behaviour of the
assembled devices of a complete wheelchair.
This document does not apply to resistance to ignition of structural parts of a wheelchair. This document does
not cover changes in resistance to ignition as a result of regular washing or use of the postural support devices.
This document allows for the separate testing of components of a wheelchair that are normally used in the
horizontal plane (e.g. a seat cushion) from those normally used in the vertical plane (e.g. a back support).
This document describes testing an assembly of the composite of materials as used in the component. The
results of the teststest in this document do not give any indication of the resistance to ignition of any of the
separate individual materials of the test sample.
NOTE 1 The intent of this document is primarily to address components that interface with the human body, such as
cushions for positioning, or whose described purpose is that of protecting skin tissue against pressure, shear, and
maceration related damage, as well as textile, foam, and plastic-based postural support devices.
NOTE 2 The pass criteria within this document have been set at a basic minimal level and can differ from current
requirements in some countries.
NOTE 3 Requirements for the control of risks from sources of fire created by electrical and electronic components are
included in ISO 7176-14.
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 7176--26:2007, Wheelchairs — Part 26: Vocabulary
ISO 8191-1:1987, Furniture — Assessment of the ignitability of upholstered furniture — Part 1: Ignition source:
smouldering cigarette
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7176–-26 and the following apply.
ISO and IEC maintain terminologicalterminology 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 3.1
flaming
undergoing combustion in the gaseous phase with the emission of light
[SOURCE: ISO 8191–-1:1987, 3.2]
3.2 3.2
non-integrated
detachable without the use of tools
Note 1 to entry: Seat or back support cushions held in place by hook and loop fastenings are also considered non-
integrated.
3.3 3.3
postural support device
PSD
structure, attached to a wheelchair, that has a surface that contacts the occupant’s body and is used either to
support, correct or stabilise the occupant’s sitting posture
EXAMPLE seat Seat, back support, lateral support, head support, pelvic positioning belt, anterior trunk support.
[SOURCE: ISO 7176-26:2007, 4.7.3 modified — The deprecated term “postural support” has been removed.
In; in the definition, “modify or accommodate” has been changed to “support, correct or stabilise”.]
3.4 3.4
smouldering
exothermic oxidation, not accompanied by flaming (3.1(3.1),), that is self-propagating, i.e. without an external
ignition source
Note 1 to entry: It is possible that smouldering is accompanied by incandescence.
4 Principle
Test materials used in integrated and non-integrated seat and back supports, and other postural support
devices as used in wheelchairs are assembled in either horizontal or vertical samples and subjected to a heat
source that is equivalent to a smouldering cigarette in its thermal output and capacity to ignite materials used
in wheelchair seating. The resulting effects on the test materials are observed and measured.
NOTE The tests are repeated a second time to ensure that they are repeatable, but without incurring the costs of
more tests than needed as a minimum.
ISO/DISPRF 16840-10:2026(en)
5 Health and safety of test personnel
5.1 General
WARNING — The following test requirements call for the use of procedures that can be hazardous to
health if adequate precautions are not taken.
The precautions listed in 5.25.2 and 5.35.3 are drawn from ISO 8191–-1:1987, Clause 6.
Ensure that there is no hidden smouldering of the sample before disposal.
5.2 Enclosure
For safety, the tests should be conducted in a non-combustible fume cupboard. If such a cupboard is not
available, a test enclosure shall be constructed (see 6.26.2)) so that the operator is protected from the fumes.
5.3 Extinguishers
Adequate means of extinguishing the assembly shall be provided, bearing in mind that some product
combinations can produce severe flaming during the test.
NOTE A hand and/or a fixed water spray that can be directed over the burning area can be useful. Other means such
as fire extinguishers (water and halogenated hydrocarbons), fire blankets, and a bucket of water will assist in
extinguishing. In some cases, smouldering can be difficult to extinguish completely and complete immersion in water can
be necessary.
6 Apparatus
6.1 Test enclosure
The test enclosure shall consist of either a room or a smaller enclosure designed to extract smoke and fumes
for the protection of the lab technician. In absence of such conditions, the technician shall take other
precautions against smoke inhalation. The enclosure shall be capable of controlled air flow to meet the
requirements specified in 6.46.4.

Note: NOTE This airflow has been determined to provide adequate airflow to exhaust smoke and feed oxygen for
ignition, without extinguishing any burning.
6.2 Timer
A means of measuring time for a period of 5 s to 1 000 s with an accuracy of ±0,1 s.
6.3 Heat source
6.3.1 General
A hot wire coil of NiCr alloy resistance wire, heated by a DC power supply that has a constant current output
mode.
NOTE 1 This source has been designed and validated to approximate the heat output and thermal mass of a burning
cigarette as determined by observing the ignition behaviour and resulting burn patterns from a variety of cigarettes. The
repeatability of the ignition behaviour and resulting burn pattern from the device was validated through interlaboratory
testing.
.
6.3.36.3.2 Wire coil
The wire shall be made from a nickel-chromium alloy containing 60- % to 80 % nickel, commonly known as
Nichrome 60, 70, or 80. The wire shall have a nominal size of 0,4mm4 mm diameter (26 AWG).
NOTE 1 The heat source calibration protocol (7.4(7.4)) accounts for small differences in electrical resistance due to
the alloy or diameter.
The wire shall be wound to produce a wire coil with the specifications shown in Figure 1Figure 1.
NOTE 2 A method for winding the wire coil to these specifications is provided in Annex AAnnex A.
Dimensions in millimetres
Figure 1 — Dimensions of wire coil
6.3.46.3.3 Power supply and connection to wire coil
The power supply shall be capable of producing a constant current between 1 A and 5 A with adjustments in
0,1 A increments. The wire coil shall be connected to the power supply by a means to ensure good electrical
conductivity.
NOTE 1 Crocodile [(alligator]) clips on high-temperature silicone insulated wire leads are an effective means of
connection.
NOTE 2 S
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