Overview
ISO 16840-2:2018/Amd 1:2024 is an important amendment to the international standard on wheelchair seating cushions, specifically focusing on the determination of physical and mechanical characteristics of seat cushions intended to manage tissue integrity. This amendment updates testing methods and introduces a new annex addressing alternatively sized cushions.
Developed by ISO Technical Committee ISO/TC 173, Subcommittee SC 1 on wheelchairs, this amendment ensures more comprehensive and accurate assessment protocols to help manufacturers and clinicians evaluate cushions designed to prevent pressure injuries and promote skin health in wheelchair users. The standard provides precise guidelines on load application, measurement techniques, and indenter dimensions for simulating anatomical loading conditions.
Key Topics
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Updated Indenter Specifications
The amendment revises the dimensions and spacing of indenters that simulate anatomical pressure points, including:
- Two 50 mm diameter indenters spaced 110 mm apart for ischial tuberosities
- Two 25 mm diameter indenters spaced 350 mm apart for the trochanters
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Testing Procedures
Detailed procedures for applying vertical loads to cushions and measuring deflections are updated for accuracy, including the application of incremental loads (140 N, 186 N, and 232 N) and the measurement of vertical distances at specified time intervals.
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Calculation Methods
It defines formulas for calculating loaded contour depth and overload deflections at 33% and 66%, essential parameters for cushioning performance that help determine how the cushion responds under pressure.
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Alternatively Sized Cushions
New annexes (D and E) specify testing configurations and parameters for cushions outside the typical width range of 400 mm to 450 mm. These annexes describe:
- Custom indenter dimensions for cushion widths ranging from 300 mm to over 500 mm
- Adjusted applied loads to reflect different cushion sizes and pressure distribution areas
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Reporting Requirements
Test reports must include median values for loaded contour depth and overload deflections to support reliable comparison of cushioning products.
Applications
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Wheelchair Cushion Manufacturers
Implement testing protocols consistent with ISO 16840-2:2018/Amd 1:2024 to certify product performance claims regarding tissue integrity management. This supports product development, quality assurance, and compliance with international standards.
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Healthcare Providers and Clinicians
Use standardized test data to select appropriate wheelchair cushions that reduce the risk of pressure ulcers in patients. The updated methods enable better clinical decision-making based on objective physical and mechanical cushion properties.
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Research and Development
Facilitate innovation in cushion materials and design by providing a robust framework to compare new products against established benchmarks for pressure management and mechanical behavior.
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Regulatory Bodies and Testing Laboratories
Adopt the amendment’s testing protocols for certification and conformity assessment processes, ensuring that cushions marketed for tissue integrity management meet internationally recognized criteria.
Related Standards
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ISO 16840 Series
This amendment is part of the ISO 16840 series dedicated to wheelchair seating evaluation, including:
- ISO 16840-1: Wheelchair seating Part 1 – Vocabulary and general requirements
- ISO 16840-3: Determination of physical and mechanical characteristics of wheelchair back cushions
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ISO/IEC Directives, Part 1 and 2
The document adheres to these directives governing the development, approval, and editorial practices of ISO standards.
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ISO TC 173 Assistive Products Standards
Connects with broader guidelines on assistive technology products addressing wheelchair and seating system safety, performance, and usability.
Keywords: ISO 16840-2 amendment, wheelchair seating standard, seat cushion testing, tissue integrity management, cushion mechanical properties, pressure relief cushions, wheelchair cushion dimensions, international wheelchair standards, cushion deflection measurement, alternatively sized cushions.
Open preview (PDF)Wheelchair seating — Part 2: Determination of physical and mechanical characteristics of seat cushions intended to manage tissue integrity — Amendment 1: Updates and addition of new Annex covering alternatively sized cushions