ISO 22568-4:2021

Overview

ISO 22568-4:2021 specifies requirements and test methods for non-metallic perforation resistant inserts used as components of PPE footwear (for example in footwear conforming to ISO 20345, ISO 20346 and ISO 20347). The standard defines how to evaluate mechanical perforation resistance, flexing durability, environmental stability and (optionally) electrical resistance of inserts intended to protect the foot and sole from sharp objects.

Key topics and technical requirements

• Perforation resistance (Types PL and PS)
  • Type PL: tested with a conical nail of 4.5 mm diameter (Method PL, Annex A). All four reported results must “pass” at 1100 N and no “tent effect” is allowed.
  • Type PS: tested with a conical nail of 3.0 mm diameter (Method PS, Annex B). The average perforation force must be ≥ 1100 N, and no single value may be < 950 N. Type PS is intended for higher risk from smaller/sharper objects.
• Flexing resistance
  • Inserts must show no cracking, delamination or disintegration after 1,000,000 flexion cycles when tested per the defined flexing apparatus and procedure.
• Stability against ageing and environmental influence
  • Inserts must retain perforation resistance after exposure to critical environments: high temperature, acid sweat, alkali sweat and fuel oil (sampling and treatments specified in the standard).
• Electrical resistance (optional)
  • An electrical resistance test is provided for applications where footwear electrical properties are relevant. Results are informative; ISO 22568-4 does not set pass/fail limits.
• Sampling and test reporting
  • The standard specifies sample numbers for unshaped materials and ready-shaped inserts, detailed test procedures (Annexes A and B), and requirements for uncertainty estimation and reporting.
• Marking and documentation
  • Requirements for marking tested components are included to allow traceability and correct application in PPE footwear assemblies.

Applications and who uses this standard

ISO 22568-4 is used by:

• Footwear component manufacturers to design, qualify and certify non-metallic perforation resistant inserts for safety, protective and occupational footwear.
• Footwear and sole manufacturers assessing suitability of inserts for specific boot or shoe constructions.
• PPE testers and certification bodies performing standardized laboratory evaluations of perforation resistance and durability.
• Procurement and safety managers specifying performance requirements for footwear in construction, manufacturing, utilities, oil/gas and other high-risk industries.

Practical benefits include consistent test methods for comparing materials, demonstrating compliance when integrating inserts into footwear, and supporting product selection based on quantified perforation and durability performance.

Related standards

• ISO 20344 - Test methods for footwear
• ISO 20345, ISO 20346, ISO 20347 - Safety, protective and occupational footwear standards

Keywords: ISO 22568-4, non-metallic perforation resistant inserts, PPE footwear, perforation resistance, flexing resistance, footwear components, test methods, ISO 20345.