ISO 7173:2023
(Main)Furniture — Chairs and stools — Determination of strength and durability
Furniture — Chairs and stools — Determination of strength and durability
This document specifies test methods for the determination of strength and durability of the structure of all types of seating without specific regard to end use, materials, design/construction or manufacturing process. This document does not apply to children’s highchairs, table mounted chairs and bath seats. Test methods for the assessment of ageing, degradation, ergonomics and electrical functions are not included. The test methods are not intended to assess the durability of upholstery materials.
Ameublement — Chaises et tabourets — Détermination de la résistance et de la durabilité
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INTERNATIONAL ISO
STANDARD 7173
Second edition
2023-08
Furniture — Chairs and stools —
Determination of strength and
durability
Ameublement — Chaises et tabourets — Détermination de la
résistance et de la durabilité
Reference number
ISO 7173:2023(E)
© ISO 2023
---------------------- Page: 1 ----------------------
ISO 7173:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2023 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 7173:2023(E)
Contents Page
Foreword . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General test conditions .3
4.1 Preliminary preparation . 3
4.2 Application of forces . 3
4.3 Tolerances . 3
5 Test equipment and apparatus .4
5.1 General . 4
5.2 Seat loading point template. 4
5.3 Floor . 7
5.4 Stops . 7
5.5 Seat loading pad. 7
5.6 Smaller seat loading pad . 7
5.7 Back loading pad . 8
5.8 Local loading pad. 8
5.9 Foam for use with loading pads . 8
5.10 Seat impactor . 8
5.10.1 General . 8
5.10.2 Circular body . 8
5.10.3 Springs . 9
5.10.4 Striking surface . 9
5.11 Impact hammer . 9
5.12 Armrest durability test apparatus . 10
5.13 Test surface for castor testing . 11
5.14 Front load locator device . 11
5.15 Loading discs . . 11
6 Test procedures – Seating other than work chairs .11
6.1 General . 11
6.2 Determination of seat and back loading points .12
6.2.1 General .12
6.2.2 Seating with a backrest .12
6.2.3 Seating without a backrest .12
6.3 Determination of angle of backrest inclination . . 13
6.4 Seat static load and backrest static load test . 14
6.4.1 General . 14
6.4.2 Seating with rocking runners . 15
6.5 Seat front edge static load test . 16
6.6 Vertical load test on backrests . 16
6.7 Horizontal forward static load test on backrests. 17
6.8 Footrest static load test . 17
6.9 Apply a vertical force by means of the local loading pad (5.8) — Legrest static load
test . 18
6.10 Armrest sideways static load test . 18
6.11 Arm rest downwards static load test . 19
6.12 Headrest static load test . 20
6.13 Vertical upwards static load test on armrests . 20
6.13.1 Seating which can be moved when occupied . 20
6.13.2 Stacking seating . 20
6.14 Vertical static load test on auxiliary writing surfaces . 20
6.15 Leg forward static load test . 20
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ISO 7173:2023(E)
6.16 Leg sideways static load test .22
6.17 Combined seat and backrest durability test . 23
6.17.1 General .23
6.17.2 Seating with rocking runners . 24
6.18 Seat front edge durability test . 26
6.19 Durability test on outdoor seating with a multi-position backrest . 27
6.20 Armrest durability test .28
6.21 Footrest durability test .28
6.22 Auxiliary writing surfaces durability test .28
6.23 Tipping seat operation test .28
6.24 Seat impact test .29
6.25 Backrest impact test . 29
6.26 Armrest impact test .30
6.27 Drop tests . 31
6.27.1 Drop test for multiple seat units . 31
6.27.2 Drop test for stacking seating . 32
6.27.3 Drop test from the height of a table . 33
6.28 Backward fall test . 33
6.29 Castor and chair base durability test .34
6.29.1 Castor and chair base durability test for chairs with castors on all legs .34
6.29.2 Castor and chair base durability test for chairs with castor and glide
combinations .34
6.30 Rolling resistance test of the unloaded chair .34
6.31 Seat side-to-side durability test in D-G points for single column seating .34
6.31.1 General .34
6.31.2 Loading points .34
7 Test procedures – Work chairs .35
7.1 General . 35
7.2 Loading points . 37
7.2.1 General . 37
7.2.2 Loading point A . 37
7.2.3 Loading point B . 37
7.2.4 Loading point C . 37
7.2.5 Loading point D . 37
7.2.6 Loading point E . 37
7.2.7 Loading point F . 37
7.2.8 Loading point G . 37
7.2.9 Loading point H . 37
7.2.10 Loading point J . 37
7.3 Combined seat and backrest static load test.39
7.4 Seat front edge static load test .39
7.5 Armrest downward static load test – central .39
7.6 Armrest downward static load test – front .40
7.7 Armrest sideways static load test .40
7.8 Footrest static load test .40
7.9 Seat and backrest durability test . 41
7.10 Armrest durability test . 42
7.11 Swivel test . 42
7.12 Footrest durability test . 42
7.13 Castor and chair base durability test . 42
7.14 Rolling resistance test of the unloaded chair . 42
8 Test procedures – Loungers .42
8.1 General . 42
8.2 Seat and backrest static load test . 43
8.3 Additional seat and legrest static load test . 43
8.4 Seat and backrest durability test .44
8.4.1 Seat and backrest durability test procedure .44
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ISO 7173:2023(E)
8.4.2 Additional seat durability test procedure .44
8.5 Durability test on backrest mechanism . 45
8.6 Armrest downwards static load test . 45
8.7 Armrest durability test . 45
8.8 Impact test . 45
8.9 Lifting test for mobile loungers . 47
9 Test report .47
Annex A (normative) Seat loading pad data .48
Annex B (informative) Armrest loading pad details .51
Annex C (normative) Front load locator device (5.14) .52
Annex D (informative) Purpose and applicability of test methods .57
Annex E (informative) Suggested loads and cycles .62
Annex F (informative) Example construction of front load locator device .68
Bibliography .70
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ISO 7173:2023(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 136, Furniture.
This second edition cancels and replaces the first edition (ISO 7173:1989), which has been technically
revised.
The main changes are as follows:
— the scope has been revised;
— terms and definitions were added;
— test methods for work chairs and seating other than work chairs were added;
— new Annexes were added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
vi
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INTERNATIONAL STANDARD ISO 7173:2023(E)
Furniture — Chairs and stools — Determination of
strength and durability
1 Scope
This document specifies test methods for the determination of strength and durability of the
structure of all types of seating without specific regard to end use, materials, design/construction or
manufacturing process.
This document does not apply to children’s highchairs, table mounted chairs and bath seats.
Test methods for the assessment of ageing, degradation, ergonomics and electrical functions are not
included.
The test methods are not intended to assess the durability of upholstery materials.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 48-4, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 4: Indentation
hardness by durometer method (Shore hardness)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
structure
load bearing parts of furniture such as the frame, seat, backrest and arm supports and suspension
3.2
legrest
extension of the seat area intended to support the legs of the user
Note 1 to entry: A legrest can or cannot be permanently attached to the structure of the item of seating and may
not be suitable for use as an item of seating itself.
3.3
footrest
extension of the seat area, whether attached or not to the structure of the item of seating, intended to
support the feet of the user
1
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ISO 7173:2023(E)
3.4
work chair
swivelling chair, with or without arm rests, for use by one adult for office work (for example working
with a computer), whose upper part, which includes the seat and backrest, is supported on a single
column and can rotate in the horizontal plane and is at least adjustable in height
3.5
backrest
element that supports the back of the user higher than 200 mm above the seat loading point
3.6
armrest
part of the seating able to support the arms of the user when seated, 100 mm or higher above the height
of the seat loading point
3.7
armrest length
horizontal distance along the armrest within an envelope down from the top of the armrest that is
20 mm deep
Note 1 to entry: See Figure 1.
Dimensions in millimetres
Key
1 armrest
l armrest length
1
Figure 1 — Armrest length
[SOURCE: ISO 24496:2021, 3.3, modified – "horizontal" added and Note 1 to entry adapted to correct
Figure number.]
3.8
multiple seating unit
unit with a seating surface wider/longer than 1 100 mm
3.9
lounger
item of seating intended for reclined posture with at least one backrest position such that backrest
angle is 45° or less to the horizontal, and a leg rest which is an integral part of the product and intended
to support the full body mass of a user
Note 1 to entry: See example in Figure 37.
2
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ISO 7173:2023(E)
3.10
single column seating
item
...
DRAFT INTERNATIONAL STANDARD
ISO/DIS 7173
ISO/TC 136 Secretariat: UNI
Voting begins on: Voting terminates on:
2022-05-19 2022-08-11
Furniture — Chairs and stools — Determination of
strength and durability
Ameublement — Chaises et tabourets — Détermination de la résistance et de la durabilité
ICS: 97.140; 97.140
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
This document is circulated as received from the committee secretariat.
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 7173:2022(E)
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 SUPPORTING DOCUMENTATION. © ISO 2022
---------------------- Page: 1 ----------------------
ISO/DIS 7173:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/DIS 7173:2022(E)
Contents Page
Foreword . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General test condition .3
4.1 Preliminary preparation . 3
4.2 Application of forces . 3
4.3 Tolerances . 3
5 Test equipment and apparatus .4
5.1 General . 4
5.2 Seat loading point template. 4
5.3 Floor . 7
5.4 Stops . 7
5.5 Seat loading pad. 7
5.6 Smaller seat loading pad . 7
5.7 Back loading pad . 8
5.8 Local loading pad. 8
5.9 Foam for use with loading pads . 8
5.10 Seat impactor . 8
5.10.1 Circular body . 8
5.10.2 Springs . 9
5.10.3 Striking surface . 9
5.11 Impact hammer . 9
5.12 Armrest durability test apparatus . 10
5.13 Test surface for castor testing . 11
5.14 Front load locator device . 11
5.15 Loading discs . . 11
6 Test procedures – Seating other than work chairs .11
6.1 General . 11
6.2 Determination of seat and back loading points .12
6.2.1 General .12
6.2.2 Seating with a backrest .12
6.2.3 Seating without a backrest .12
6.3 Determination of angle of backrest inclination . . 14
6.4 Seat static load and backrest static load test . 15
6.5 Seat front edge static load test . 17
6.6 Vertical load test on backrests . 17
6.7 Horizontal forward static load test on backrests. 17
6.8 Footrest static load test . 18
6.9 Legrest static load test . 19
6.10 Armrest sideways static load test . 19
6.11 Arm rest downwards static load test . 19
6.12 Headrest static load test . 20
6.13 Vertical upwards static load test on armrests . 20
6.13.1 Seating which can be moved when occupied . 20
6.13.2 Stacking seating . 21
6.14 Vertical static load test on auxiliary writing surfaces . 21
6.15 Leg forward static load test . 21
6.16 Leg sideways static load test .22
6.17 Combined seat and backrest durability test . 24
6.18 Seat front edge durability test . 27
6.19 Durability test on outdoor seating with a multi-position backrest . 27
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ISO/DIS 7173:2022(E)
6.20 Armrest durability test .28
6.21 Footrest durability test .28
6.22 Auxiliary writing surfaces durability test .28
6.23 Tipping seat operation test .28
6.24 Seat impact test .29
6.25 Backrest impact test . 29
6.26 Armrest impact test .30
6.27 Drop tests . 31
6.27.1 Drop test for stacking seating . 32
6.27.2 Drop test from the height of a table . 33
6.28 Backward fall test . 33
6.29 Castor and chair base durability test .34
6.29.1 Castor and chair base durability test for chairs with castors on all legs .34
6.29.2 Castor and chair base durability test for chairs with castor and glide
combinations .34
6.30 Rolling resistance test of the unloaded chair .34
6.31 Seat side-to-side durability test in D-G points for single column seating .34
6.31.1 Loading points .34
7 Test procedures – Work Chairs .35
7.1 General . 35
7.2 Loading points . 37
7.2.1 General . 37
7.2.2 Loading point A . 37
7.2.3 Loading point B . 37
7.2.4 Loading point C . 37
7.2.5 Loading point D . 37
7.2.6 Loading point E . 37
7.2.7 Loading point F . 37
7.2.8 Loading point G . 37
7.2.9 Loading point H . 37
7.2.10 Loading point J . 37
7.3 Combined seat and backrest static load test.39
7.4 Seat front edge static load test .39
7.5 Armrest downward static load test – central .39
7.6 Armrest downward static load test – front .40
7.7 Armrest sideways static load test .40
7.8 Footrest static load test .40
7.9 Seat and backrest durability test . 41
7.10 Armrest durability test . 42
7.11 Swivel test . 42
7.12 Footrest durability test . 42
7.13 Castor and chair base durability test . 42
7.14 Rolling resistance test of the unloaded chair . 42
8 Test procedures – Loungers .42
8.1 General . 42
8.2 Seat and backrest static load test . 43
8.3 Additional seat and legrest static load test . 43
8.4 Seat and backrest durability test .44
8.4.1 Seat and backrest durability test procedure .44
8.4.2 Additional seat durability test procedure .44
8.5 Durability test on backrest mechanism . 45
8.6 Armrest downwards static load test . 45
8.7 Armrest durability test . 45
8.8 Impact test . 45
8.9 Lifting test for mobile loungers . 47
Annex A (normative) Seat loading pad data . .48
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ISO/DIS 7173:2022(E)
Annex B (informative) Armrest loading pad details .51
Annex C (normative) Front load locator device (5.14) .52
Annex D (informative) Purpose and applicability of test methods .58
Annex E (informative) Suggested loads and cycles .64
Bibliography .70
v
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---------------------- Page: 5 ----------------------
ISO/DIS 7173:2022(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 136, Funiture.
This second edition cancels and replaces the first edition (ISO 7173:1989), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Scope has been revised;
— Further terms and definitions were added;
— Further test methods for work chairs and seating other than work chairs were added;
— New Annexes were added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
vi
© ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 7173:2022(E)
Furniture — Chairs and stools — Determination of
strength and durability
1 Scope
This International Standard specifies test methods for the determination of strength and durability
of the structure of all types of seating without regard to use, materials, design/construction or
manufacturing process.
This International Standard does not apply to children’s highchairs, table mounted chairs and bath
seats.
Test methods for the assessment of ageing, degradation, ergonomics and electrical functions are not
included.
The test methods are not intended to assess the durability of upholstery materials, such as upholstery
filling materials and upholstery covers.
This International Standard does not include any requirements. Requirements for different end uses
can be found in other Standards.
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 48-4:2018, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 4: Indentation
hardness by durometer method (Shore hardness)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
structure
load bearing parts of furniture such as the frame, seat, backrest and arm supports and suspension
3.2
legrest
extension of the seat area intended to support the legs of the user
Note 1 to entry: A legrest can or cannot be permanently attached to the structure of the item of seating, and may
not be suitable for use as an item of seating itself.
3.3
footrest
extension of the seat area, whether attached or not to the structure of the item of seating, intended to
support the feet of the user
1
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ISO/DIS 7173:2022(E)
3.4
work chair
swivelling chair, with or without arm rests, for use by one adult in the office (for example working with
a computer), whose upper part, which includes the seat and backrest, is supported on a single column
and can rotate in the horizontal plane and is at least adjustable in height
3.5
backrest
element that supports the back of the user higher than 200 mm above the seat loading point
3.6
armrest
part of the seating able to support the arms of the user when seated, 100 mm or higher above the height
of the seat loading point
3.7
armrest length
horizontal distance along the armrest within an envelope down from the top of the armrest that is
20 mm deep
Note 1 to entry: See Figure 1.
Key
1 armrest
l armrest length
1
Figure 1 — Armrest length
[SOURCE: ISO 24496:2021, 3.3; modified – "horizontal" added and Note 1 to entry adapted to correct
Figure number.]
3.8
multiple seating unit
unit with a seating surface wider/longer than 1 100 mm
3.9
lounger
item of seating intended for reclined posture with at least one backrest position such that backrest
angle is 45 degrees or less to the horizontal, and a leg rest which is an integral part of the product and
intended to support the full body weight of a user
Note 1 to entry: See Figure 37.
2
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/DIS 7173:2022(E)
3.10
single column seating
item of seating, whose upper part, which includes the seat, is mounted on a single support with a
diameter of up to 120 mm at its narrowest point
4 General test condition
4.1 Preliminary preparation
The furniture shall be tested as delivered. Knock-down furniture shall be assembled according to the
instructions supplied with it. If the instructions allow the furniture to be assembled or combined in
different ways, the most adverse combination shall be used for each test. Knock-down fittings shall be
tightened before testing. Further tightening shall not take place.
For seating that is designed to be fixed to the structure of a building, the unit shall be mo
...
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