Overview
ISO 5423:1992 specifies requirements for moulded plastics footwear - specifically lined or unlined polyurethane (PU) boots for general industrial use. It covers materials, minimum dimensions, physical properties, test methods and marking. The standard applies to boots from ankle to full-thigh height and includes normative annexes for thickness measurement, flexing resistance, soling flex tests, strength tests and test-piece preparation (Annexes A–E). Annex F gives suggested boot heights (informative).
Key keywords: ISO 5423, moulded plastics footwear, polyurethane boots, industrial boots, boot specifications, flexing resistance, hardness, thickness measurement.
Key topics and technical requirements
- Scope and materials
- Applies to boots moulded from homogeneously mixed polyurethane compound (cellular or combined cellular/non‑cellular). Uppers, soling and heel must be moulded from PU.
- Design and minimum thicknesses
- Minimum thickness values are specified and must be measured per Annex A (measurement procedures for upper, foxing, outsole, heel and full boot bottom).
- Physical properties and tests
- Resistance to flexing (Annex B): Upper material must withstand specified flex cycles (typically up to 150 000 cycles) without specified cracking patterns.
- Soling flex (Annex C) and cut-growth/flexing behaviour measured at low temperature (e.g., −5 °C) with limits on growth after cycles.
- Tensile properties: Modulus at 100% elongation and elongation at break for upper and soling compounds (tested per ISO 37).
- Hardness: IRHD limits for upper and soling/heel materials (measured per ISO 48).
- Split tear strength: Minimum split tear strength for cellular soling (given in the standard).
- Resistance to hydrolysis: Limits on change in elongation after conditioning (Annex E preparation).
- Marking
- Each article must be indelibly marked with size, manufacturer/supplier identification, and the ISO 5423 reference.
Applications and who uses this standard
- Footwear manufacturers and moulders producing PU industrial boots
- Product designers and R&D teams validating compound selection and component design
- Quality control and testing laboratories performing compliance tests (thickness, flexing, hardness, tensile and hydrolysis)
- Procurement specialists and safety managers specifying industrial safety footwear
- Certification bodies and regulators assessing conformity to footwear performance requirements
Related standards
ISO 5423 references and aligns test methods with other ISO documents including:
- ISO 37 (tensile stress-strain)
- ISO 48 (hardness, IRHD)
- ISO 458‑1 (cold flex testing)
- ISO 10335 (nomenclature for rubber/plastics footwear)
- ISO/R 463 (dial gauges)
Use ISO 5423 when specifying or testing PU moulded industrial boots to ensure repeatable, documented performance for durability, low‑temperature flexing and material integrity.
Open preview (PDF)Moulded plastics footwear — Lined or unlined polyurethane boots for general industrial use — Specification