ISO 3385:2014

Overview

ISO 3385:2014 - Flexible cellular polymeric materials - Determination of fatigue by constant-load pounding - specifies a laboratory method to assess loss in thickness and loss in hardness of flexible cellular polymeric materials (e.g., rubber-latex and polyurethane foams) intended for load-bearing applications such as upholstery. The standard defines test pieces, conditioning, pounding equipment, test cycles and result reporting to provide repeatable measures of fatigue performance under a constant-load indentation load.

Key topics and technical requirements

• Scope: Applies to slabstock test pieces and shaped components; results indicate service-related losses but are not exact predictions of in-service behaviour. ISO 3385:2014 is not a detailed engineering design specification for fatigue apparatus.
• Apparatus: Two machine types are described:
  • Type A: Mechanical crank/suspended-weight arrangement where full load is applied briefly in each cycle.
  • Type B: Fully controlled electro‑/pneumatic/servo-hydraulic machine equipped with a load cell (force-measurement precision ±1 %).
• Indentor and platen: Indentor diameter 250 mm ±1 mm with 25 mm ±1 mm radius; maximum peak force controlled at 750 N ±20 N (never to exceed 770 N). Platen must vent air to avoid compression artefacts.
• Cycle parameters: Indentation frequency (70 ±5) strokes per minute; dwell at peak load limited to ≤10 % of cycle time. Typical test run: 80 000 continuous load cycles.
• Test pieces and conditioning: Standard test pieces usually 380 mm × 380 mm ±20 mm by 50 mm ±2 mm thickness. Condition specimens for at least 16 h at either 23 °C/50 % RH or 27 °C/65 % RH; do not test earlier than 72 h after manufacture unless validated.
• Measurements and results: Measure original and post-fatigue thickness and hardness (as per ISO 2439 Method A). Report percentage thickness loss and hardness loss (absolute and percent), expressed as the median of three specimens.
• Reporting: Test report must reference ISO 3385, material description, conditioning, machine type, orientation, and median losses.

Applications and users

• Practical for foam manufacturers, material R&D teams, quality control labs, upholstery and furniture suppliers, and third‑party testing bodies assessing load-bearing foam durability.
• Useful for material comparison, specification compliance, supplier qualification, and product development decisions where indentation fatigue (pounding) resistance is required.

Related standards

• ISO 2439:2008 - Flexible cellular polymeric materials - Determination of hardness (indentation technique) - referenced for hardness measurement procedures.

Keywords: ISO 3385:2014, flexible cellular polymeric materials, fatigue by constant-load pounding, loss in thickness, loss in hardness, upholstery foam testing, polyurethane foam, rubber-latex foam, pounding test machine.