EN 17850:2023

SLOVENSKI STANDARD
01-februar-2024
Pohištveno okovje - Podstavki za sedežno pohištvo - Zahteve in preskusne
metode
Hardware for furniture - Star bases for seating - Requirements and test methods
Möbelbeschläge - Fußkreuze für Sitzmöbel - Anforderungen und Prüfverfahren
Quincaillerie d'ameublement - Piètement en étoile pour sièges - Exigences et méthodes
d'essai
Ta slovenski standard je istoveten z: EN 17850:2023
ICS:
97.140 Pohištvo Furniture
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 17850
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2023
EUROPÄISCHE NORM
ICS 97.140
English Version
Hardware for furniture - Star bases for seating -
Requirements and test methods
Quincaillerie d'ameublement - Piètements en étoile Möbelbeschläge - Fußkreuze für Sitzmöbel -
pour sièges - Exigences et méthodes d'essai Anforderungen und Prüfverfahren
This European Standard was approved by CEN on 27 November 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17850:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 General test conditions . 5
4.1 Preliminary preparation . 5
4.2 Tolerances . 5
5 Test equipment . 5
5.1 Counter cone . 5
5.2 Castor simulation device . 5
5.3 Castor/Glide stem . 6
5.4 Test device for torsion and deflection . 6
5.5 Floor . 7
5.6 Seat simulation lever . 7
6 Test procedures and requirements . 8
6.1 General . 8
6.2 Base Test – Static Overload . 8
6.3 Strength test – off centre. 9
6.4 Deformation under torsion .10
6.5 Durability test – vertical .12
7 Product information .13
8 Test report .13
Bibliography .14

European foreword
This document (EN 17850:2023) has been prepared by Technical Committee CEN/TC 207 “Furniture”,
the secretariat of which is held by UNI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2024, and conflicting national standards shall be
withdrawn at the latest by June 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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 the United
Kingdom.
1 Scope
This document specifies requirements and test methods for the determination of the strength, durability
and stiffness of star bases for use for seating with three or more legs.
It is not applicable for star bases intended to be used in child seating products.
It is applicable without regard to materials, design/construction or manufacturing processes.
It is a component standard helping to regulate star-base properties between component manufacturer
and manufacturer of final seating. This document is not relevant for the final consumer where standards
for complete articles exist.
The requirements are based upon star bases fitted with glides and with castors whose wheels are up to
65 mm diameter and for use by persons weighing up to 150 kg.
2 Normative references
There are no normative references in this document.
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
star base
undercarriage for a seating with three or more legs supported/carried with castors or glides at the ends
and with a centre mounting hole for a column (i.e. a gaslift or similar with conical centre hole)
3.2
castor
assembly comprising a housing, one or more wheels, an axle and, if required, accessories
3.3
glide
foot with stem that allows a chair to be moved while protecting the floor
3.4
counter cone
conical device to transfer the relevant load to the base
3.5
excess length
length of part of the stem protruding out of the mounting hole
4 General test conditions
4.1 Preliminary preparation
Unless otherwise stated, all samples which include structural parts made of hygroscopic materials, e.g.
polyamide shall be conditioned at (23 ± 2) °C and (50 ± 5) % RH for at least seven days before testing.
Non–hygroscopic materials shall be conditioned at (23 ± 2) °C and (50 ± 5) % RH for at least 6 h.
Unless otherwise stated, the tests shall be carried out in indoor ambient conditions at (20 ± 5) °C, and a
relative humidity of (50 ± 5) %. If during a test the temperature/humidity is outside of these conditions,
the maximum and/or minimum temperature/humidity shall be recorded in the test report.
Any information given by the manufacturer of the star base shall be taken into consideration.
4.2 Tolerances
Unless otherwise stated the following tolerances are applicable:
 forces: ± 5 % of the nominal force;
 time: ± 5 % of the nominal time;
 masses: ± 1 % of the nominal mass;
 dimensions:
 all dimensions less than 300 mm shall have a tolerance of ± 1,0 mm of the nominal dimension;
 all other dimensions shall have a tolerance of ± 0,5 % of the nominal dimension;
 angles: ± 1,0° of the nominal angle.
NOTE For the purposes of uncertainty measurement, test results are not considered to be adversely affected
when the above tolerances are met.
5 Test equipment
5.1 Counter cone
The counter cone shall be made of steel with a smooth surface, and it shall be able to cover the full surface
of the base cone. The cone diameter is to be adapted to the size of the mounting hole of the base.
In case a counter cone is supplied by the manufacturer this counter cone can be used and this shall be
recorded in the test report.
NOTE 1 The surface roughness R for polished steel is usually < 6,3 µm.
Z
NOTE 2 A typical cone angle for a gas spring is 1,438 ° (1 ° 26’ 16”) (example see ISO 296, Conus Type 3).
5.2 Castor simulation device
A device which includes a stem and two wheels, which simulates castors with 65 mm diameter wheels
(F = 22 mm), see Figure 1. If the star base is intended to be used with castors with wheels of more than
65 mm diameter, the dimension F of the castor simulating device shall be modified accordingly and the
wheel diameter and the dimension F shall be recorded in the test report.
The stem shall fit the mounting hole for the castor. The device shall not prevent the deformation of the
legs in horizontal or vertical directions.
Figure 1 shows an example of a standard castor application with the relevant dimensions.
It is acceptable to use stem delivered by star base manufacturer instead of the one of castor simulation
device. Use of this stem part shall be recorded in the test report.
NOTE In most cases, the bases are intended to be used with castors according to EN 12529.
Dimensions in millimetres
Key
P diameter of the stem
l length of the stem
F distance from the centre of the castor to the centre the stem
Figure 1 — Example of a castor simulation device
5.3 Castor/Glide stem
A stem which fits to the mounting hole for the castor/glide.
In case the stem is not used with castors the excess length is 20 mm.
It is acceptable to use stem delivered by star base manufacturer instead of the one of castor simulation
device. Use of this stem part shall be recorded in the test report.
NOTE In most cases, castor stems with a diameter of 10 mm or 11 mm are common.
5.4 Test device for torsion and deflection
Lever arm made of a steel square tube with dimensions of 20 mm in width, 50 mm in height and
1 125 mm in length and a weight of 2,6 kg (including the angle measuring device). The attachment point
to the base leg is located at the centre of the lever arm. Attachment points for torsion forces are located
at 390 mm and 500 mm from the centre hole (see Figure 2). The lever arm shall fit tight on the stem rising
out of the centre hole not more than 5 mm (see Figure 2, item 2). The lever arm shall not touch the leg of
the star base (distance max. 5 mm).
Point p is the centre of the top of the stem (see Figure 2).
It is acceptable to use stem delivered by star base manufacturer instead of the one of test device for
torsion and deflection. Use of this stem part shall be recorded in the test report.

Dimensions in millimetres
Key
1 lever arm
2 stem
3 base leg (base upside down)
4 attachment points for torsion forces
p top of the centre of stem
Figure 2 — Lever arm
5.5 Floor
Smooth, flat and rigid steel surface.
5.6 Seat simulation lever
Device that allows simulating the off-centre forces to the centre mounting hole of the base.
The cone is made of steel with a smooth surface and shall have the same properties as described in 5.1.
The lever shall be made of steel and mounted to the cone (see Figure 3) and shall have a length L which
allows transferring the required load to the specific points as requested in 6.3.
The offset h of the top of the lever above the star base shall be less than 100 mm.
10 2
The lever shall have a stiffness value (EI) of not less than 1,4 x 10 Nmm corresponding e.g. to a profile
of 50 mm in width and 25 mm in height.
The weight of the device shall no
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