Anthropometry of Wheeled Mobility Project: Final Report

4.3.5.4 360-degree Turn

Accommodation models for 360-degree turns have been developed for the three types of devices based on the results (e.g. Figure 4‒7). There are substantial differences between the device types. Scooters require the largest turning spaces and manual chairs the least although there are some manual chair users that required spaces as large as many power chair users. The use of the 95th percentile in the power chair findings would increase the current requirements by 575 mm (23 in.). The size of the space required for the 95th percentile of scooter users would create even larger increases. Thus, due to the potential impact, these findings require some policy decisions on who to exclude, or a new way to address this design issue.

Dimensions for 360-degree turning spaces are used to determine the minimum spaces needed for turning around in spaces with only one point of entry. To better represent these situations, we based our measurements on a square-shaped space rather than circular as the former allows WhMD users to use the corners thereby optimizing space utilization. In spaces in which turning around is not critical for usability, another basis for determining the minimum floor area can be used as in the Fair Housing Accessibility Guidelines which only require a clear floor space outside the arc of a swinging door. This strategy is also already used for elevators and toilet stalls in the ADA-ABA Guidelines. A second strategy is to provide a turning space in all covered public spaces like toilet rooms, laundries and shared kitchenettes to accommodate the 50th or 75th percentile and, in addition, require at least one of each type of space somewhere in a building to be large enough to accommodate the largest devices. For example, one companion toilet room could be required in every building that accommodates both assisted use and the largest devices while the other toilet rooms meet less space intensive requirements. The largest turning space could also be required in places where the impact of increasing turning spaces is insignificant, for example, in a lobby or outdoors. Obviously, better space planning can also be used to avoid dead end spaces entirely but that cannot be mandated in a standard.

The implications of these findings are so significant that the authors recommend starting broad discussion of options among stakeholders before a concrete proposal is made to adopt a particular strategy.

Figure 4-7: Accommodation model depicting the minimum clear space required by users of manual wheelchairs, powered chairs and scooters to complete a 360-degree turn.

Long Description: This data depicts the amount of space required by users of wheeled mobility devices to perform a 360-degree turn. The bold dashed line in the table and figure indicates the current ADA requirement of a 152.5 cm (60 in.) turn space. Findings from the Anthropometry of Wheeled Mobility Study indicate that a square space of at least 160 x 160 cm (63 in.) was required for 50% of the manual wheelchair users measured in this study to perform a 360-degree turn. A space of 210 x 210 cm (83 in.) was required in order for 95% of manual wheelchair and power chair users to complete the turn, with 95% of scooter users needing a space of at least 250 x 250 cm (98 in.) These data are based on measurements of wheeled mobility users performing 360-degree turns within an enclosed square space built with mock walls. The enclosed space was incrementally varied from a size of 130 x 130 cm (51 in.) to 250 x 250 cm (98 in.) The minimum space required for completing 360-degree turn within moving or knocking down any of the walls was recorded. Use of multiple short turns was allowed in contrast to a single continuous turn.