Wheelchair seating

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. NOTEÂ Â Â Â Â 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.

Sièges de fauteuils roulants

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Published
Publication Date
07-Jun-2021
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5060 - Close of voting Proof returned by Secretariat
Start Date
06-May-2021
Completion Date
06-May-2021
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INTERNATIONAL ISO
STANDARD 16840-10
Second edition
2021-06
Wheelchair seating —
Part 10:
Resistance to ignition of postural
support devices — Requirements and
test method
Sièges de fauteuils roulants —
Partie 10: Résistance à l'inflammation des dispositifs de soutien
postural — Exigences et méthode d'essai
Reference number
ISO 16840-10:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 16840-10:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 16840-10:2021(E)
Contents Page

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 rig ............................................................................................................................................................................................................ 3

6.2 Test enclosure .......................................................................................................................................................................................... 3

6.3 Timer ............................................................................................................................................................................................................... 3

6.4 Heat source................................................................................................................................................................................................. 3

6.5 Conditioning environment ............................................................................................................................................................ 6

6.6 Test environment .................................................................................................................................................................................. 6

6.7 Test sample ................................................................................................................................................................................................. 6

6.7.1 General...................................................................................................................................................................................... 6

6.7.2 Seat and back support cushions ......................................................................................................................... 6

6.7.3 Other postural support devices .......................................................................................................................... 6

7 Test procedure ........................................................................................................................................................................................................ 7

7.1 Preparation ................................................................................................................................................................................................ 7

7.2 Horizontal test ......................................................................................................................................................................................... 7

7.3 Vertical test................................................................................................................................................................................................. 7

7.4 Smaller PSDs ............................................................................................................................................................................................. 8

8 Requirements .......................................................................................................................................................................................................... 9

9 Test report ................................................................................................................................................................................................................... 9

10 Disclosure of results ......................................................................................................................................................................................10

Annex A (informative) Design of a heat source as a surrogate cigarette device...................................................11

Annex B (normative) Conditioning of removable covering materials by washing and drying

procedures ...............................................................................................................................................................................................................15

Annex C (informative) Selection of surface(s) at risk, to be used for testing ..........................................................17

Bibliography .............................................................................................................................................................................................................................18

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 16840-10:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 173, Assistive products, Subcommittee SC

1, Wheelchairs.

This second edition of ISO 16840-10 cancels and replaces ISO 16840-10:2014 and ISO 7176-16:2012,

which have been technically revised.
The main changes compared to the previous edition are as follows:

— inclusion of the other postural support devices originally covered by ISO 7176-16:2012 rather than

just seat and back support cushions;
— inclusion of integrated as well as non-integrated postural support devices;

— provision for postural support devices that are smaller than the specified test sample size;

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 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 16840-10:2021(E)
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 that most 21 century flammability

[8]
incidents 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 test

methods 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.

At the time of publication of this document, 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 standardized

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

standardized heat source output comparable with that employed in the original flammability standards,

and that can be scaled to equate with other heat sources.

The pass criteria within this document have been set at a basic minimum level and are less severe

than current requirements in some countries. However, given the minimal risks of flammability as a

© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 16840-10:2021(E)

hazard in wheelchair seating and the significant potentially adverse health effects of flame retardants,

strong consideration should be given to utilizing this document as the ignition resistance standard for

all wheelchair seating textiles/soft components that interface with the human body. Eliminating the

more severe flame resistance required by furniture standards and in ISO 7176-16:2012 allows the use

of more clinically appropriate textiles for the health and comfort of the wheelchair user.

Good practice is also to use materials that minimize the risk of release of toxic substances as a result

of ignition and that do not pose a biocompatibility risk to the wheelchair user. The change of emphasis

around the materials to use minimizes 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 are required to conform to biocompatibility requirements and risk management guidance of

ISO 10993–1, which includes consideration of cytotoxicity, sensitization, and irritation evaluation for

surface devices in contact with the skin as covered by ISO 10993-5 and ISO 10993-10.

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 a non-combustible 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 © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 16840-10:2021(E)
Wheelchair seating —
Part 10:
Resistance to ignition of postural support devices —
Requirements and test method
1 Scope

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.

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 554, Standard atmospheres for conditioning and/or testing — Specifications

ISO 7176-15, Wheelchairs — Part 15: Requirements for information disclosure, documentation and labelling

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
ISO 14971, Medical devices — Application of risk management to medical devices
© ISO 2021 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO 16840-10:2021(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 7176–26 and ISO 8191–1:1987

and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// 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 modify or to accommodate 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]
3.4
progressive smouldering

exothermic oxidation, not accompanied by flaming (3.1), that is self-propagating, i.e. independent of the

ignition source
Note 1 to entry: It might or might not be accompanied by incandescence.
[SOURCE: ISO 8191–1:1987, 3.1]
4 Principle

Test materials used in integrated and non-integrated seat and back support, 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. The resulting effects on the test materials are

observed and measured.

NOTE The tests are repeated one time to ensure that they are repeatable, but without incurring the costs of

more tests than needed as a minimum

The pass criteria within this document have been set at a basic minimal level and are less severe than

current requirements in some countries. Where practical, manufacturers shall use materials with

superior resistance to ignition, when the overall risk analysis indicates the benefits outweigh any

unintended harm, in accordance with ISO 14971.
2 © ISO 2021 – All rights reserved
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ISO 16840-10:2021(E)
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.
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 is 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 rig
An example of a suitable test rig is found in ISO 8191–1:1987.

NOTE The frame of the test rig described as the back frame with a width of 450 mm ± 2 mm, but with a

height of 450 mm ± 2 mm can be used for both the horizontal and vertical tests.
6.2 Test enclosure

The test enclosure shall consist of either a room with a volume greater than 20 m (that contains

adequate oxygen for testing) or a smaller enclosure with a through flow of air. Inlet and extraction

systems providing air flows of 0,02 m/s to 0,2 m/s in the locality of the rig provide adequate oxygen

without disturbing the burning behaviour.
NOTE This enclosure is the equivalent to that specified in ISO 8191–1:1987, 7.2.
6.3 Timer

A means of measuring time for a period of 5 s to 1 000 s with an accuracy of ±0,1 s.

6.4 Heat source
A temperature-controlled heat source consisting of two separate parts.
a) A heat source conforming to the following:
— 8 mm ± 0,5 mm diameter;
— 75 mm ± 5 mm heated length;
© ISO 2021 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 16840-10:2021(E)
— 200 W ± 20 W heat output;
— K-type thermocouple integrated in the centre of the heat source;
— minimum wire length of 3 m;
— heat resistant wire insulation;

— a fixture to hold the heat source in place throughout the test, designed to avoid burns while

handling the heat source.
b) A temperature controller conforming to the following:

— temperature controller with automatic identification of the control area or model based tuning

of the controller parameters;

— the temperature values follow the temperature heating curve in Figure 1 and Table 1

automatically during the test cycle.
NOTE 1 Annex A provides details of an apparatus that meets these specifications.

NOTE 2 This source has been designed to give a calorific output approximating to that of a stabilized

smouldering cigarette (ISO 8191–1:1987).

NOTE 3 By adjusting the parameters of the set point curve, this apparatus can be utilised to simulate a ‘match’

or other heat source.

NOTE 4 Other means, such as a NiCr coil, that achieve the same heat transfer to the test sample, can be used as

an alternative heat source.
4 © ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 16840-10:2021(E)
Key
X time (s)
Y °C
A warming heat source phase

B test cycle phase (step-down tolerances allows time for devices to adjust to setpoint)

C cooling heat source phase
1 application of heat source and beginning of test cycle
2 end of test cycle and removal of heat source
ramp down (cooling)
ramp up (heating)
plateau (set point)
minimum value (+ tolerance)
maximum value (- tolerance)

Figure 1 — Temperature-time-diagram of the test cycle with set point curve and allowed

tolerances
Table 1 — Set point table for the test
Duration Initial set point Final set point
Ramp Variable <150 °C 575 ± 30 °C
Plateau 30 s ± 1 s 575 °C ± 30 °C 575 °C ± 10 °C
Plateau 30 s ± 1 s 575 °C ± 10 °C 575 °C ± 10 °C
© ISO 2021 – All rights reserved 5
---------------------- Page: 11 ----------------------
ISO 16840-10:2021(E)
6.5 Conditioning environment

Prior to conditioning described below, all removable covering materials shall be subjected to the

washing and drying procedures described in Annex B.

An environment with an atmosphere that can be maintained for up to 20 h at a temperature of

23 °C ± 2 °C and relative humidity of 50 % ± 5 % as specified in ISO 554 shall be employed.

6.6 Test environment

An environment in which the test procedure in Clause 7 can be conducted and that has an atmosphere

with a temperature between 10 °C and 30 °C and a relative humidity between 15 % and 80 %.

In the area of the test rig within 100 mm ± 5 mm of the heat source, the airflow shall be less than

0,2 m/s.
6.7 Test sample
6.7.1 General

6.7.1.1 Test samples shall be in new or unused condition. A test sample shall consist of the materials

as assembled in the final product, and include: cover, filling, and any other components (such as an

interliner) that can possibly be used.

Spray-on flame retardant substances shall not be relied on unless the durability of their effectiveness

for the life of the manufactured part is confirmed.

6.7.1.2 If the postural support device is designed to be used only with its cover, then the test sample

shall include that cover.

6.7.1.3 If the postural support device is designed to be used only with its cover from a choice of covers,

each cover option shall be tested separately in combination with that device.

6.7.1.4 If the postural support device is designed to be used either with or without its cover, then the

device shall be tested with and without its cover.
6.7.2 Seat and back support cushions

The sample shall have dimensions of a minimum width of 300 mm and a maximum width of 450 mm,

and a depth or length of a minimum of 300 mm and a maximum of 450 mm.

NOTE A manufactured, non-integrated seat or back support cushion, provided that it is no smaller than the

minimum dimensions or no larger than the maximum dimensions specified above, can be used.

6.7.3 Other postural support devices

Use a sample consisting of materials assembled as used in the relevant postural support device, and

with dimensions comprising a minimum width of 30 mm in one dimension and a length of a minimum

of 150 mm in the second dimension, and flat over at least 95 % of the surface projection.

A manufactured part may be used, provided that it is no smaller than the minimum dimensions.

6 © ISO 2021 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 16840-10:2021(E)
7 Test procedure
7.1 Preparation
a) Identify the PSD.

b) Select the surface(s) that the manufacturer assesses to be at risk from a fire source (see Annex C).

c) If testing items that are intended to be used only in the range of the horizontal plane ±30°, use the

horizontal test, and for all other supports, use the vertical test. If the part is intended for use in

either plane, then only the vertical test is necessary.
d) Attach the test sample(s) to the test rig(s).

e) Place the test rig and sample in the conditioning environment for a minimum of 16 h.

f) Ensure the heat source i
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 16840-10
ISO/TC 173/SC 1
Wheelchair seating —
Secretariat: SABS
Voting begins on:
Part 10:
2021-04-09
Resistance to ignition of postural
Voting terminates on:
support devices — Requirements and
2021-06-04
test methods
Fauteuils roulants —
Partie 10: Résistance à l'inflammation des coussins de sièges et de
dossiers non intégrés — Exigences et méthodes d'essai
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 16840-10:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 16840-10:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 16840-10:2021(E)
Contents Page

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 rig ............................................................................................................................................................................................................ 3

6.2 Test enclosure .......................................................................................................................................................................................... 3

6.3 Timer ............................................................................................................................................................................................................... 3

6.4 Heat source................................................................................................................................................................................................. 3

6.5 Conditioning environment ............................................................................................................................................................ 5

6.6 Test environment .................................................................................................................................................................................. 6

6.7 Test sample ................................................................................................................................................................................................. 6

6.7.1 General...................................................................................................................................................................................... 6

6.7.2 Seat and back support cushions ......................................................................................................................... 6

6.7.3 Other postural support devices .......................................................................................................................... 6

7 Test procedure ........................................................................................................................................................................................................ 6

7.1 Preparation ................................................................................................................................................................................................ 6

7.2 Horizontal test ......................................................................................................................................................................................... 7

7.3 Vertical test................................................................................................................................................................................................. 7

7.4 Smaller PSDs ............................................................................................................................................................................................. 8

8 Requirements .......................................................................................................................................................................................................... 9

9 Test report ................................................................................................................................................................................................................... 9

10 Disclosure of results ......................................................................................................................................................................................10

Annex A (informative) Design of a heat source as a surrogate cigarette device...................................................11

Annex B (normative) Conditioning of outer cover materials by washing and drying procedures ...15

Annex C (informative) Selection of surface(s) at risk, to be used for testing ..........................................................17

Bibliography .............................................................................................................................................................................................................................18

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 16840-10:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical ISO/TC 173, Assistive products, Subcommittee SC 1,

Wheelchairs.

This second edition cancels and replaces the first edition (ISO 16840-10:2014), which has been

technically revised.
The main changes compared to the previous edition are as follows:

— inclusion of the other postural support devices originally covered by ISO 7176-16:2012 rather than

just seat and back support cushions;
— inclusion of integrated as well as non-integrated postural support devices;

— provision for postural support devices that are smaller than the specified test sample size;

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.
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ISO/FDIS 16840-10:2021(E)
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 that most 21 century flammability

[8]
incidents 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 test

methods 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.

At the time of publication of this document, 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 standardized

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

standardized heat source output comparable with that employed in the original flammability standards,

and that can be scaled to equate with other heat sources.

The pass criteria within this document have been set at a basic minimum level and are less severe

than current requirements in some countries. However, given the minimal risks of flammability as a

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ISO/FDIS 16840-10:2021(E)

hazard in wheelchair seating and the significant potentially adverse health effects of flame retardants,

strong consideration should be given to utilizing this document as the ignition resistance standard for

all wheelchair seating textiles/soft components that interface with the human body. Eliminating the

more severe flame resistance required by furniture standards and in ISO 7176-16:2012 allows the use

of more clinically appropriate textiles for the health and comfort of the wheelchair user.

Good practice is also to use materials that minimize the risk of release of toxic substances as a result

of ignition and that do not pose a biocompatibility risk to the wheelchair user. The change of emphasis

around the materials to use minimizes 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 are required to conform to biocompatibility requirements and risk management guidance of

ISO 10993–1, which includes consideration of cytotoxicity, sensitization, and irritation evaluation for

surface devices in contact with the skin as covered by ISO 10993-5 and ISO 10993-10.

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.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 16840-10:2021(E)
Wheelchair seating —
Part 10:
Resistance to ignition of postural support devices —
Requirements and test methods
1 Scope

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.

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 554, Standard atmospheres for conditioning and/or testing — Specifications

ISO 7176-15, Wheelchairs — Part 15: Requirements for information disclosure, documentation and labelling

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
ISO 14971, Medical devices — Application of risk management to medical devices
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ISO/FDIS 16840-10:2021(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 7176–26 and ISO 8191–1:1987

and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// 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 modify or to accommodate 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]
3.4
progressive smouldering

exothermic oxidation, not accompanied by flaming (3.1), that is self-propagating, i.e. independent of the

ignition source
Note 1 to entry: It can or cannot be accompanied by incandescence.
[SOURCE: ISO 8191–1:1987, 3.1]
4 Principle

Test materials used in integrated and non-integrated seat and back support, 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. The resulting effects on the test materials are

observed and measured.

NOTE The tests are repeated one time to ensure that they are repeatable, but without incurring the costs of

more tests than needed as a minimum

The pass criteria within this document have been set at a basic minimal level and are less severe than

current requirements in some countries. Where practical, manufacturers shall use materials with

superior resistance to ignition, when the overall risk analysis indicates the benefits outweigh any

unintended harm, in accordance with ISO 14971.
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ISO/FDIS 16840-10:2021(E)
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.

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 rig
An example of a suitable test rig is found in ISO 8191–1:1987.

NOTE The frame of the test rig described as the back frame with a width of 450 mm ± 2 mm, but with a

height of 450 mm ± 2 mm can be used for both the horizontal and vertical tests.
6.2 Test enclosure

The test enclosure shall consist of either a room with a volume greater than 20 m (that contains

adequate oxygen for testing) or a smaller enclosure with a through flow of air. Inlet and extraction

systems providing air flows of 0,02 m/s to 0,2 m/s in the locality of the rig provide adequate oxygen

without disturbing the burning behaviour.
NOTE This enclosure is the equivalent to that specified in ISO 8191–1:1987, 7.2.
6.3 Timer

A means of measuring time for a period of 5 s to 1 000 s with an accuracy of ±0,1 s.

6.4 Heat source
A temperature-controlled heat source consisting of two separate parts.
a) A heat source conforming to the following:
— 8 mm ± 0,5 mm diameter;
— 75 mm ± 5 mm heated length;
— 200 W ± 20 W heat output;
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ISO/FDIS 16840-10:2021(E)
— K-type thermocouple integrated in the centre of the heat source;
— minimum wire length of 3 m;
— heat resistant wire insulation;

— a fixture to hold the heat source in place throughout the test, designed to avoid burns while

handling the heat source.
b) A temperature controller conforming to the following:

— temperature controller with automatic identification of the control area or model based tuning

of the controller parameters;

— the temperature values follow the temperature heating curve in Figure 1 and Table 1

automatically during the test cycle.
NOTE 1 Annex A provides details of an apparatus that meets these specifications.

NOTE 2 This source has been designed to give a calorific output approximating to that of a stabilized

smouldering cigarette (ISO 8191–1:1987).

NOTE 3 By adjusting the parameters of the set point curve, this apparatus can be utilised to simulate a ‘match’

or other heat source.

NOTE 4 Other means, such as a NiCr coil, that achieve the same heat transfer to the test sample, can be used as

an alternative heat source.
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ISO/FDIS 16840-10:2021(E)
Key
X time (s)
Y °C
A warming heat source phase

B test cycle phase (step-down tolerances allows time for devices to adjust to setpoint)

C cooling heat source phase
1 application of heat source and beginning of test cycle
2 end of test cycle and removal of heat source
set point
minimum value
maximum value

Figure 1 — Temperature-time-diagram of the test cycle with set point curve and allowed offset

Table 1 — Set point table for the test
Duration Initial set point Final set point
Ramp Variable <150 °C 575 ± 30 °C
Plateau 30 s ± 1 s 575 °C ± 30 °C 575 °C ± 10 °C
Plateau 30 s ± 1 s 575 °C ± 10 °C 575 °C ± 10 °C
6.5 Conditioning environment

Prior to conditioning described below, all outer cover materials shall be subjected to the washing and

drying procedures described in Annex B.

An environment with an atmosphere that can be maintained for up to 20 h at a temperature of

23 °C ± 2 °C and relative humidity of 50 % ± 5 % as specified in ISO 554 shall be employed.

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ISO/FDIS 16840-10:2021(E)
6.6 Test environment

An environment in which the test procedure in Clause 7 can be conducted and that has an atmosphere

with a temperature between 10 °C and 30 °C and a relative humidity between 15 % and 80 %.

In the area of the test rig within 100 mm ± 5 mm of the heat source, the airflow shall be less than

0,02 m/s.
6.7 Test sample
6.7.1 General

6.7.1.1 Test samples shall be in new or unused condition. A sample consisting of the materials as used

shall be assembled. This shall consists of cover, filling, and any other components (such as an interliner)

that can be used in a real assembly.

Spray-on flame retardant substances shall not be relied on unless the durability of their effectiveness

for the life of the manufactured part is confirmed.

6.7.1.2 If the postural support device is designed to be used only with its cover, then the test sample

shall include that cover.

6.7.1.3 If the postural support device is designed to be used only with its cover from a choice of covers,

each cover option shall be tested separately in combination with that device.

6.7.1.4 If the postural support device is designed to be used either with or without its cover, then the

device shall be tested with and without its cover.
6.7.2 Seat and back support cushions

The sample shall have dimensions of a minimum width of 300 mm and a maximum width of 450 mm,

and a depth or length of a minimum of 300 mm and a maximum of 450 mm.

NOTE A manufactured, non-integrated seat or back support cushion, provided that it is no smaller than the

minimum dimensions or no larger than the maximum dimensions specified above, can be used.

6.7.3 Other postural support devices

Use a sample consisting of materials assembled as used in the relevant postural support device, and

with dimensions comprising a minimum width of 30 mm in one dimension and a length of a minimum

of 150 mm in the second dimension, and flat over at least 95 % of the surface projection.

A manufactured part may be used, provided that it is no smaller than the minimum dimensions.

7 Test procedure
7.1 Preparation
a) Identify the PSD.

b) Select the surface(s) that the manufacturer assesses to be at risk from a fire source (see Annex C).

c) If testing items that are intended to be used only in the range of the horizontal plane ±30°, use the

horizontal test, and for all other supports, use the vertical test. If the part is intended for use in

either plane, then
...

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