In December 2023,
a new standard for star bases for seating has been published, implemented by UNI on 25thof January, 2024. The scope is to define the 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.
These requirements are based upon
star bases fitted with glides and with castors, with a maximum diameter of 65 mm, and for use by person weighing up to 150 kg. The
tests requested and described by the standard are:
- Base test – static overload
- Strength test – off centre
- Deformation under torsion
- Durability test - vertical
Before testing, the samples to be tested are conditioned as follows:
- Samples made of hygroscopic material (e.g.: polyamide) at least seven days at (23±2) °C and (50±5) %RH
- Samples made of non-hygroscopic material at least six hours at (23±2) °C and (50±5) %RH.
The tests shall be carried out in indoor ambient conditions at (20±5) °C and a relative humidity of (50±5) %RH.
To carry out these tests, are necessary:
- Four samples (hygroscopic material)
- Five samples (non-hygroscopic material)
A short description of the tests is following.
Base test – static overload, clause 6.2The test consists of the application of a force of 11.120 N which is maintained for 1 minute; the force is then removed and the procedure repeated a second time after 2 minutes. The force is applied by means of a cone inserted into the central hole of the base.
Strength test – off centre, clause 6.3The test is carried out applying a force of 2.200 N over a period of 10/12 seconds and it is maintained for 5 seconds; the force is then removed and the procedure repeated for a total of 10 cycles. The force is applied using a special device consisting of an arm and a cone which is inserted into the central hole of the base; the point of application of the force is moved, with respect to the axis of the pins or wheels, by 50 mm towards the center of the sample base along one of its legs.
Deformation under torsion, clause 6.4In the case of non-hygroscopic material, a sample must be conditioned for at least 6 hours at (23±2) °C and (50±5) %RH.
In the case of hygroscopic material, there must be 2 samples and they must be conditioned as follows:
- Sample 1 at least seven days at (23±2) °C and (50±5) %RH
- Sample 2 at least seven days at (40±2) °C and (70±5) %RH
The base is placed, in upwards position, on a cone fixed to the test basement. A lever arm is then inserted on one of the pins (or wheel pins) of the base itself. The distance between the insertion point of the arm and the ends of the arm itself are 500 mm and 390 mm respectively. By simultaneously applying 25 kg to each end of the arm, a torque applied to the arm of the sample base equal to 28 Nm is determined. The load is then maintained for 2 hours, after which the degrees of torsion and the bending of the base are measured. The load is then removed and after another 2 hours from the removal the torsion and bending measurements are repeated.
The requirements are different if the base is made of hygroscopic material or not.
Durability test - vertical, clause 6.5The test is carried out applying a force of 2.500 N to the center of the base, for a total of 120,000 cycles. The maximum frequency is 60 cycles/min for metal bases and 30 cycles/min for bases in other materials. The distance of the lower and central part of the base to the floor is measured after 100 cycles and at the end of the test.
Product information, clause 7Standard provides this minimum information:
- Reference to this document (EN 17850)
- That the base is suitable for glides or castors up to 65 mm diameter
- The base is suitable for person weighing up to 150 kg
The above information can otherwise be given by pictograms.
CATAS is equipped with the testing facility to perform the tests according to this standard and is therefore able to satisfy the requests of seat bases manufacturers.
We are always available for information on this matter.
For info:
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