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Wheelchair standards

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Wheelchair standards are detailed test and measurement methods designed to create consistent information about the features and performance of wheelchairs. Since the early 1980s, standards organizations, such as the American National Standards Institute (ANSI), Rehabilitation Engineering and Assistive Technology Society of North America (RESNA), and the International Standardization Organization (ISO), have collaborated to develop seating and transport safety standards to be followed in the development of wheelchairs. There are two volumes of standards by ANSI/RESNA published in 1998: Volume 1 contains requirements and test methods for manual and electric wheelchairs and scooters and Volume 2 contains additional standards for electric wheelchairs and scooters only. These include requirements for design, performance, test methods, and information disclosure. The ISO sets the required minimum and maximum values of certain attributes of the wheelchair.

The use of a standardization process among wheelchair manufacturers and designers greatly reduces inconsistencies between the previously different methods of measurements, testing procedures, and the reporting of results. For example, “seat width” could have meant the measurement between the inside of the seat rails to one manufacturer, or between the outside of the seat rails to another, or between the armrests to yet another manufacturer. ANSI/RESNA wheelchair standards were established to eliminate these inconsistencies and provide uniform methods for analyzing wheelchairs and prescribing the chair by therapists.

In addition, the ISO sets minimum performance criteria that must be met before the wheelchair can be put on the market for the safety of consumers, such as fatigue tests. The purpose of a fatigue test is to simulate the effects of curbs by subjecting a wheelchair to a series of small obstructions and drops. Volume 1 of the ANSI/RESNA standards states specific instructions in test preparation for both manual and electric wheelchairs, evaluation of test results, and the required contents of the test report. Test results must be compared to and in compliance with the ISO requirements. The ISO standards also include maximum values for certain characteristics, including mass, stability, turning space, and dimensions of a wheelchair, such as overall length, width, and height, in order to ensure the safety of wheelchair users.

Some categories require separate procedures and standards for manual and powerchairs due to the nature of the feature, such as braking mechanisms. For manual wheelchairs, the brakes must be adjusted to hold the loaded wheelchair in place when facing up or down a slope inclined at 7° +1/-0 to the horizontal. The mean of three test runs must be calculated and compared to the maximum operating force values, respective to which type of brake is used on the wheelchair: hand-operated (60 N), foot push operation (100 N), or food pull operation (60 N). For electric wheelchairs, the parking brake must be tested (similar to the brake test for manual wheelchairs) as well as the running brake. The running brake test requires that the wheelchair be driven forwards at maximum speed across a horizontal plane then brought to a stop by releasing the control device. The length between where the control was released and where the wheelchair actually came to a stop, the braking distance, must then be measured. The braking distances should also be measured with the wheelchair traveling backwards on a horizontal plane, and forwards on 3°, 6°, and 10° inclined planes. All tests are to be completed three times and a mean braking distance calculated for each.

LINKS:

1. ANSI- American National Standards Institute
<http://www.ansi.org>
2. RESNA- Rehabilitation Engineering and Assistive Technology Society of North America
<http://www.resna.org>
3. ISO- International Standardization Organization
<http://www.iso.org>
4. Sections in ANSI/RESNA Wheelchair Standards: Volumes 1 & 2
<http://www.resna.org/ProfResources/Publications/PubDesc/WheelchairStandards.php>



Author: Charity Pires
Affiliation: CATEA at the Georgia Institute of Technology