Overview
ISO 20867:2018 - "Footwear - Test methods for insoles - Heel pin holding strength" defines a laboratory method to measure an insole component’s ability to retain a heel pin and prevent the pin head from being pulled through the insole. The method applies to insoles used with inside-attached heels and to seat components where outside heel attachments are used and the heel pin is clenched.
Key topics and technical requirements
- Scope: Determines the force required to push a simulated heel-pin head through the insole material (heel pin holding strength).
- Specimen size & sampling: Two rectangular test pieces of 80 mm × 20 mm; sampling in accordance with ISO 17709 when taken from insoles.
- Conditioning:
- Dry test piece conditioned in a standard atmosphere per ISO 18454 for a minimum of 48 h.
- Wet test piece soaked in water at 23 °C ± 2 °C for 6 h, then tested after blotting.
- Apparatus:
- Drill: 2.0 mm ± 0.1 mm twist bit.
- Tensile-testing machine (dynamometer) meeting ISO 5893, constant traverse 100 mm/min ± 20 mm/min.
- Test attachment: plate with 12 mm hole and a rod with 2 mm shank and 4.0 mm ± 0.2 mm head (simulates 8 × 14 mm gauge heel pin).
- Dial micrometer gauge with 3.85 N ± 0.10 N loading and 0.01 mm resolution for thickness measurements.
- Test procedure:
- Drill three holes at 20, 40 and 60 mm along the centre line.
- For each hole, push the rod head from the foot side and record the maximum force until failure.
- Repeat for dry and wet specimens.
- Results & reporting:
- Express heel pin holding strength as the mean of three maximum forces (newtons) for dry and wet specimens.
- Report mean specimen thickness and include full test details (reference ISO 20867:2018, sample ID, deviations, atmosphere, date, etc.).
Applications and users
- Footwear manufacturers and component suppliers validating insole design and heel attachment durability.
- Quality control and materials testing laboratories performing standardized insole tests.
- R&D teams comparing construction methods or materials for heel retention.
- Compliance and procurement specialists specifying performance criteria for insole components.
Related standards
- ISO 5893 - tensile-testing machine requirements
- ISO 17709 - sampling location and conditioning of footwear test pieces
- ISO 18454 - standard atmospheres for conditioning and testing
Keywords: ISO 20867:2018, heel pin holding strength, insole testing, footwear testing standard, tensile-testing machine, dry testing, wet testing, insole quality control.