ISO 19957:2021 PDF

Overview

ISO 19957:2021 - "Footwear - Test methods for heels - Heel pin holding strength" specifies a standardized laboratory method to measure the force required to pull a single heel pin out of a heel. The procedure is used both to evaluate the intrinsic heel pin holding strength of heel materials (using a standard heel pin and controlled insertion) and to assess heel nailing in commercial production. This method applies to plastics and wooden heels for women’s footwear; it is not suitable for heels made from layered fibreboard or leather, or for low plastics heels for men’s footwear.

Key topics and technical requirements

• Scope and applicability: Measures pull-out force for a single standard heel pin to determine heel pin holding strength and to evaluate production heel nailing.
• Apparatus:
  • Tensile testing machine conforming to ISO 7500-1, class 2, range ~0–2 000 N, traverse 40 mm/min ± 10 mm/min.
  • Standard heel pin (length 18 ± 0.5 mm, buttress diameter ≥ 1.9 mm, specified buttress flanks and spacing).
  • Heel nailing machine, small clamp/slotted hook, 2 mm metal rod for mounting.
• Sampling & preparation:
  • Lab specimens: typically 3 heels × 6 pins (or 4 heels × 4 pins); when testing made shoes, prepare equivalent specimens where possible.
  • Insertion control: use cellulose discs during pin insertion to ensure correct pin depth (5–8 mm of pin remaining).
  • Attachment: drill ≈Ø2 mm hole through heel (typically 20–25 mm from top) for anchoring; alternate clamping for narrow/stiletto stems.
• Test procedure:
  • Pull pin approximately parallel to shaft; record maximum load at removal.
  • Traverse rate: 40 mm/min ± 10 mm/min.
  • Measure penetration depth (d) with fine wire; inspect interior for cavities or incorrect insertion.
  • Obtain at least 12 valid pull-out results for material assessment.
• Result expression:
  • Heel pin holding strength h (N/mm) = F / (d − 4), where F = max pull-out load (N), d = measured depth (mm). Report averages and individual values.

Applications and users

ISO 19957:2021 is used for:

• Quality control and incoming inspection by footwear manufacturers.
• Production monitoring of heel nailing processes.
• Laboratory testing and material comparison for R&D and product development.
• Compliance documentation and failure analysis by test laboratories, material suppliers, and retailers.

Typical users: footwear manufacturers, test laboratories, material engineers, product designers, quality assurance teams.

Related standards

• ISO 7500-1 - Calibration and verification of static uniaxial testing machines (tension/compression), referenced for tensile machine requirements.
• ISO 19957:2021 is the second edition, revising ISO 19957:2004.

Keywords: ISO 19957:2021, heel pin holding strength, footwear testing, heel test method, tensile testing machine, standard heel pin, heel nailing, plastics heels, wooden heels.