Overview
ISO 11646:2014 - Leather - Measurement of area specifies a repeatable method for measuring the surface area of pieces of leather. The standard is intended for dressed and other dry flexible leathers and defines the use, calibration and operation of a mechanical pin-wheel area-measurement machine. It links to conditioning requirements in ISO 2419 (20 °C and 65 % RH) so that area measurements are comparable and defensible.
Key topics and technical requirements
- Measurement principle: area determined by a mechanical pin-wheel machine that counts wheel rotations as the leather passes between pin-wheels and a feed roller.
- Apparatus recommendations:
- Preferred feed-roller speed: 20 m/min ± 2 m/min.
- Recommended pin-wheel pin spacing: 25.4 mm ± 2.5 mm (centre-to-centre).
- Use a circular calibration template made of flexible reinforced material; template area should be ≥ 5 % of machine capacity and width ≤ 50 % of working width.
- Calibration:
- Daily calibration procedure before testing (warm-up passes, certified template passes).
- Template area verification at least annually by an independent body using traceable calibration; acceptable if within ±0.5 % of nominal area.
- Machine calibration tolerance for template passes: recorded total area within ±0.01 m² of theoretical total.
- Sampling and conditioning:
- Default conditioning per ISO 2419: 20 °C and 65 % RH for ≥24 h unless otherwise agreed.
- Conditioning regime must be recorded if deviated.
- Measurement technique:
- Feed the leather with the higher-friction surface against the pins; specimen must be flat and crease-free.
- Feed direction: approximately 30° for linear edges; otherwise backbone roughly perpendicular to roller axis.
