FprCEN/TS 18231:2025

SLOVENSKI STANDARD
01-november-2025
Pohištvo - Vodilo za merjenje mer po EN 1335-1 z uporabo ISO 24496 (CMD)
Furniture - Guide to measuring EN 1335-1 dimensions with ISO 24496 CMD
Möbel - Leitfaden für die messung der abmessungen nach EN 1335-1 mit ISO 24496
Mobilier - Guide pour mesurer les dimensions EN 1335-1 avec le CMD ISO 24496
Ta slovenski standard je istoveten z: FprCEN/TS 18231:2025
ICS:
97.140 Pohištvo Furniture
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 18231
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
August 2025
ICS 97.140
English Version
Furniture - Guide to measuring EN 1335-1 dimensions
with ISO 24496 CMD
Mobilier - Guide pour mesurer les dimensions EN Möbel - Leitfaden für die messung der abmessungen
1335-1 avec le CMD ISO 24496 nach EN 1335-1 mit ISO 24496

This draft Technical Specification is submitted to CEN members for Vote. It has been drawn up by the Technical Committee
CEN/TC 207.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
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.

Warning : This document is not a Technical Specification. It is distributed for review and comments. It is subject to change
without notice and shall not be referred to as a Technical Specification.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TS 18231:2025:2025 E
worldwide for CEN national Members.

Contents Page
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Guidance for chair setup and placement of CMD on chair . 6
4.1 Chair set up . 6
Figure 1— Useful lines to be marked on the chair . 7
4.2 Final placement of CMD on chair . 8
Figure 2 — Examples of lines on the CMD to assist centering the CMD in the chair . 8
Figure 3 — Placement of the CMD on the chair . 9
4.3 Further preparatory steps . 9
Figure 4 — Marking of seat width zone . 9
5 Guidance on measuring procedures . 10
5.1 General. 10
5.2 Measurements with the chair components adjusted to their middle position . 10
5.2.1 Sequence 1 - Lumbar support maximum height: fmax . 10
5.2.2 Sequence 2 - Lumbar support minimum height: fmin . 10
5.2.3 Sequence 3 - frange . 10
5.2.4 Fixed height lumbar support . 10
Figure 5 — Fixed lumbar zone . 11
5.2.5 Determination of angles γ, e and l . 11
5.2.6 Sequence 4 - Angle between seat and back: ɤ . 11
5.2.7 Sequence 5 - Angle backrest inclination range: l . 12
5.2.8 Sequence 6 - Seat pad angle adjustable and seat pad angle fixed - minimum: e (min) . 12
5.2.9 Sequence 7 - Seat pad angle adjustable and seat pad angle fixed – maximum: e (max) . 12
5.3 Measurements with the chair components adjusted to their minimum position . 12
5.3.1 General. 12
5.3.2 Sequence 8 - Seat height: a (min) . 12
Figure 6 — Measuring seat height . 13
5.3.3 Sequence 9 - Sitting height: a (min.)(see Figure 7) . 13
Figure 7 — Position of the sitting height measurement point . 13
5.3.4 Sequence 10 - Adjustable depth of the seat / Fixed depth of the seat: b (min.)(see Figure 8)
............................................................................................................................................................................. 14
Figure 8 — Seat depth indicated on the scale . 14
5.3.5 Sequence 11 - Backrest height: h (min.) . 14
Figure 9 — Measurement of backrest height . 14
5.3.6 Sequence 12 - Maximum distance from the backrest to the front of the armrests: q (max)
............................................................................................................................................................................. 15
Figure 10 — Measurement of the maximum distance from the backrest to the front of the armrests
............................................................................................................................................................................. 15
5.3.7 Sequence 13 - Height of armrests adjustable / Height of armrests not adjustable: p (min)
............................................................................................................................................................................. 15
Figure 11 — Height of the armrest . 16
5.4 Measurements with the chair components adjusted to their maximum position . 16
5.4.1 General . 16
5.4.2 Sequence 14 - Seat height: a (max.) . 16
5.4.3 Sequence 15 - Sitting height: a (max.) . 17
5.4.4 Sequence 16 - Adjustable depth of the seat / Fixed depth of the seat: b (max.). 17
5.4.5 Sequence 17 - Backrest height: h (max.) . 17
5.4.6 Sequence 18 - Height of armrests adjustable / Height of armrests not adjustable: p (max.)
............................................................................................................................................................................. 17
5.5 Measurements without the CMD on the chair . 17
5.5.1 General . 17
5.5.2 Sequence 19 - Seat pad width: d . 17
5.5.3 Sequence 20 - Seat pad depth: c . 17
5.5.4 Sequence 21 - Backrest width: j . 17
Figure 12 — Example of backrest width measurement . 18
5.5.5 Sequence 22 - Radius of backrest: k . 18
5.5.6 Sequence 23 - Armrest length: n (see Figure 13) . 18
Figure 13 — Example of armrest length callipers . 19
5.5.7 Sequence 24 - Armrest width: o (see Figure 14) . 19
Figure 14 — Example of armrest width callipers . 19
5.5.8 Sequence 25 - Maximum clearance between armrest assembly when armrests are in their
widest position: r . 19
Figure 15 — Examples of the maximum distance is defined by the distance between the armrest
assembly . 20
5.5.9 Sequence 26 - Adjustable clear distance between armrest pads / Fixed clear distance
between armrest pads: z . 20
Figure 16 — Example of the positioning of the template on curved armrest pads . 20
5.5.10 Sequence 27 - Offset of the underframe: s . 20

European foreword
This document (FprCEN/TS 18231:2025) has been prepared by Technical Committee CEN/TC 207
“Furniture”, the secretariat of which is held by UNI.
This document is currently submitted to the Vote on TS.
Introduction
This document provides guidance information on how to measure the dimensions from
EN 1335-1:2020+A1:2022 by using test methods and the chair measuring device (CMD) in
ISO 24496:2021.
They have been drawn up by a working group of experts set up by CEN/TC 207/WG3 with the prime
objective to give clear guidance on how to take measurements and avoid interpretations. This can
minimize the discrepancies between dimensions taken by different groups of measurers.
This document can be used alongside ISO 24496:2021 when determining how to take the dimensions of
the office chair.
ISO 24496:2021 and this document might not cover all situations and designs. When a measurement
cannot be taken as specified in the procedures due to the design of the product, it can be carried out as
far as possible as described, and deviations from the measurement procedure can be recorded in the test
report.
1 Scope
This document explains how to act and avoid interpretations on how to measure the dimensions of
EN 1335-1:2020+A1:2022 using the test methods and chair measurement device (CMD) of
ISO 24496:2021.
This document provides additional information not provided in ISO 24496:2021, further clarifications
and examples to make measurement of the dimensions more precise and less interpretable.
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.
EN 1335-1:2020+A1:2022, Office furniture — Office work chair — Part 1: Dimensions — Determination of
dimensions
ISO 24496:2021, Office furniture — Office chairs — Methods f
...