Recommendations on Standards for the Design of Medical Diagnostic Equipment for Adults with Disabilities, Advisory Committee Final Report

5.8.1.1 Clear Platform Size Recommendation

The Committee recommends a platform size with a minimum clear width of 32 inches and a minimum clear length of 40 inches.

Rationale for the recommendation

The platform size of 32 inches minimum width by 40 inches minimum length accommodates both manual and power wheeled mobility devices including small and mid-size scooters. This platform size may not accommodate some larger scooters with a 4-wheel base. The Wheeled Mobility Anthropometry Project recommends this platform dimension.^iv These study findings noted that a 36-inch length accommodates standard manual and power wheelchairs and most, if not all, large size-extra wide manual chairs. This size platform allows the person to maneuver and position the device even though many devices may not stop precisely in the middle of the platform.

To have an accurate weight, the entire wheelbase (either 3 or 4 wheels) of a mobility device must rest on and make contact with the platform. The foot pedals, footrests, scooter deck and tip wheels can overhang or extend beyond the platform and still get an accurate weight.^II

The Wheeled Mobility Anthropometry Project research summarizes wheelbase measurements on wheeled mobility devices shown in the table below.4

Table 5.8.1.1
Wheelbase Measurements on Wheeled Mobility Devices

Table ![sic]: Range and percentile values for wheelbase (inches) by mobility device type

[Click image above to view HTML version]

The Wheeled Mobility Anthropometry Project recommends a minimum flat surface of 40 inches length for platforms accommodating wheeled mobility devices including scooters and a minimum flat surface of 33 inches length for platforms accommodating wheeled mobility devices excluding scooters.

Figure 5.8.1.1 Clear Platform Size
(SOURCE: U.S. Access Board)

Notes

^II The IDeA Center in its research defined wheelchair wheelbase as the distance from the center of the primary drive wheel to the center of the caster measured parallel to the floor. It defines scooter wheelbase as the distance from the center of the primary drive wheels to the center of the back or front wheels measured parallel to the floor.

Section 5 References

^iv IDeA Center Study at the University of Buffalo, New York: Summary analysis of wheelbase measurements on wheeled mobility devices.