BS EN ISO 20873:2016 pdf download – Footwear — Test methods for outsoles — Dimensional stability
This international standard specifies a method for determining the linear shrinkage after heating of test specimens prepared from outsoles.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
Members of ISO and IEC maintain registers of currently valid International Standards.
Footwear – Standard atmospheres for conditioning and testing of footwear and components for footwear.
ISO 17709 Footwear — Sampling location, preparation and duration of conditioning of samples and test pieces.
Rubber, vulcanized or thermoplastic – Determination of dimensions of test pieces and products for test purposes.
For the purposes of this International Standard, the following definition applies:
the reduction in the distance between two reference points on a test piece before and after heating in air under specified conditions. This shrinkage is expressed as percentage of the initial distance 4 Apparatus and material
The following apparatus and material shall be used:
4.2 Templates and scalpel or other sharp knife, to cut two reference marks in the test specimen either 100 mm or 50 mm apart.
4.3 Oven, for heating the test specimens to 70 °C ± 2 °C and thermostatically controlled so that they are kept within 2C of the required temperature during the heating period.
4.4 Device capable of measuring the distance between two cuts, 50 mm apart or 100 mm apart, on a flat surface, to an accuracy of ± 0,2 mm.
This may consist of either:
a) a steel rule, marked in millimetres as in 4.1, together with a x5 magnifying glass;
b) a travelling microscope or similar optical device with scale.
4.5 Thickness gauge
Thickness gauge, standing on a firm base and loaded with a dead weight such that the presser foot applies a pressure of 10 kPa ± 3 kPa. The gauge has a presser foot which is flat, circular and 10 mm ± 0,1 mm in diameter,as defined in ISO 4648.
The gauge has scale division of 0,01 mm.
The test pieces to be tested are taken in accordance with ISO 17709. All test pieces shall be conditioned in accordance with ISO 18454, before testing for a minimun of 24 h.
The test samples with the full thickness of the outsoles shall be tested.
Minimum three test pieces are necessary.
6 Test methods
6.1 Test specimen piece
Using a scalpel or other sharp knife (4.2) and a steel rule (4.1), cut the test specimens to the dimensions and tolerances given in figure 1.
Make two parallel reference cuts on the external surface not more than 0,5 mm deep across the full width of the test specimen on each side of it, 100 mm ± 5 mm apart for the larger test specimen and 50 mm ± 5 mm apart for the smaller test specimen.
6.2 Measurement before heat treatment (L 0 )
Measure to within ± 0,2 mm the distance between the reference cuts along the centreline.
6.3 Heat treatment
Place the test specimens horizontally (supported in such a way as to ensure adequate air ventilation on all sides) in the oven (4.3) for 24 h ± 0,5 h at the temperature of 70 °C ± 2 °C.
6.4 Measurement after heat treatment (L)
Remove the test specimen from the oven at the end of the period of heat treatment. Keep the test specimens for at least 30 min in a standard atmosphere. If the test specimens are bowed, hold them flat for measurement. If the measuring cuts have widened, take the point of the measurement as the centre of the cut. Measure to within ± 0,2 mm the distance between these cuts along centreline as the described using an appropriate device.