ISO 16840-2:2018

Overview

ISO 16840-2:2018 - "Wheelchair seating - Part 2" - defines standardized apparatus, test methods and disclosure requirements for wheelchair seat cushions intended to manage tissue integrity. The standard characterizes the physical and mechanical properties of cushions (for pressure management and tissue protection) using repeatable laboratory tests that simulate a symmetric anatomy and posture. Tests use loads representative of the pelvis of a 50th‑percentile wheelchair user and are not intended to evaluate bariatric performance, weight capacity or fire resistance.

Key technical topics and requirements

• Apparatus and terminology: Defines cushion loading indenter (CLI), loaded contour indenter (LCI), rigid cushion loading indenter (RCLI) and impact‑damping RCLI (IDRCLI). Specifies a loading rig able to apply up to 830 N with displacement measurement to ±1 mm.
• Preparation and sequencing: Requirements for cushion selection, preconditioning, setup and the sequence of tests so results are comparable across products.
• Mechanical and physical tests:
  • Frictional properties - measures slip resistance between skin or cover and cushion surface.
  • Impact damping - evaluates cushion capacity to absorb sudden loads (IDRCLI).
  • Recovery - assesses how cushion materials rebound after loading.
  • Loaded contour depth & overload deflection - quantifies how a cushion contours under load (contour depth) and how it behaves under overload.
  • Hysteresis - evaluates energy loss and stiffness characteristics during load cycles.
  • Water spillage - tests liquid handling and containment behaviour.
  • Biocompatibility - aligns with biological safety evaluation principles.
• Reporting & disclosure: Specifies test report content and disclosure requirements so manufacturers can consistently communicate measured properties. Annexes provide typical value ranges and adaptations for different cushion sizes.
• Limitations: Tests simulate symmetric anatomy and do not guarantee individual clinical outcomes. Not all methods apply to every cushion technology.

Practical applications

• Enables manufacturers to characterize and benchmark cushion design features (contouring, damping, slip resistance).
• Provides test laboratories with standardized procedures for reproducible results.
• Helps clinicians, therapists and procurement teams compare product mechanical characteristics relevant to pressure management and tissue integrity.
• Useful for R&D (material selection, prototype evaluation) and evidence documentation for regulatory or purchasing decisions.

Who should use ISO 16840-2:2018

• Medical device and assistive‑technology manufacturers of wheelchair cushions and support surfaces
• Independent test laboratories and certification bodies
• Clinicians, seating specialists and occupational therapists involved in pressure‑management selection
• Procurement officers and standards/regulatory professionals

Related standards

• ISO 16840-1 (vocabulary and measures)
• ISO 16840-10 / ISO 7176-16 (flammability and postural support devices)
• ISO 7176-26 (vocabulary)
• ISO 10993-1 (biocompatibility)
• ISO 9073-8 (liquid strike‑through testing)

Keywords: ISO 16840-2, wheelchair seating, seat cushions, tissue integrity, cushion testing, loaded contour depth, impact damping, pressure management.