More on Wheelchair Transit Safety Standards

Hello all!

The safety of individuals who must remain seated in their wheelchairs during transit remains an important consideration for therapists prescribing wheelchairs. I have previously written articles on RESNA standards, including WC19 Wheelchairs Used as Seats in Motor Vehicles, WC18 Wheelchair Tiedown and Occupant Restraint Systems (WTORS) for Use in Motor Vehicles. and WC20 Wheelchair Seating Systems for Use in Motor Vehicles. These articles provide information that is helpful in understanding these related standards.

Therapists often ask, "How do I determine the safety of a wheelchair when my client is transported in a vehicle while sitting in it?" This question comes up when prescribing a wheelchair for an individual when it is known that the individual must remain seated in the wheelchair during transit. It also comes up when organizations, such as long-term care facilities, become aware of safety considerations in transporting individuals in wheelchairs and ask therapists to address the safety of already prescribed products. The following website on Wheelchair Transportation Safety from the University of Michigan Transportation Research Institute (UMTRI) lists crash tested products: https://wc-transportation-safety.umtri.umich.edu/. The listed wheelchairs are categorized as being "completely compliant with the requirements of WC19 (2012)", "successfully crash tested to WC19 (2012)", "completely compliant with the requirements of ISO 7176-19 (2008)" or "successfully crash tested to ISO 7176-19 (2008)". Scroll down each embedded Excel spreadsheet to see the full list of manufacturers and products. Manufacturers are listed alphabetically. It is noteworthy that there is a caveat at the bottom of the page that "Claims of product compliance are as reported by manufacturers and cannot always be confirmed by UMTRI personnel as these are voluntary industry standards."¹

Let's look at the differences between having a product be "completely compliant" versus being "successfully crash tested". We will then look at the differences between WC19 and ISO 7176-19 standards.

Completely Compliant versus Successfully Crash Tested

To understand the difference between successful crash testing and being completely compliant to a wheelchair transit standard, it is important to understand that there are both design and performance criteria that are measured and that several tests are completed on a wheelchair to determine overall compliance. A wheelchair that is "completely compliant with the requirements of WC19 (2012)" means that "the wheelchair has been successfully crash tested with a surrogate 4-point strap-type securement using a wheelchair-anchored pelvic belt, meets all design requirements, has successfully passed the tiedown clear path and securement-point accessibility tests, received at least an acceptable rating with regard to the ease of proper placement of vehicle-anchored three-point belts and to the extent to which proper positioning and geometry of a three-point belt can be achieved, as well as meeting several other requirements."¹ Whereas a wheelchair that has been "successfully crash tested" to WC19 (2012) with the frontal impact sled test "has been successfully crash tested with a surrogate 4-point strap-type securement using a wheelchair-anchored pelvic belt, but the wheelchair may not meet all of the design requirements of the standard or may not have completed all of the required tests in WC19."¹

Similarly, a wheelchair that is "completely compliant with the requirements of ISO 7176-19 (2008) …has been successfully crash tested with a commercial or surrogate 4-point strap-type securement with either a wheelchair-anchored pelvic belt OR a vehicle-anchored three-point belt, meets all design requirements, has successfully passed the securement-point accessibility test, as well as meeting several other requirements."¹ A wheelchair that has been "successfully crash tested to ISO 7176-19 (2008)" has been successfully crash tested as described above, "but the wheelchair may not meet all of the design requirements of the standard or may not have completed all of the required tests in ISO 7176-19."¹

Differences between RESNA WC19 and ISO 7176-19

Both the RESNA WC19 and ISO 7176-19 standards require successful performance on a crash test in which the wheelchair is secured to a crash test sled which undergoes a 48 kph, 20-g frontal impact.² The permitted securement of the wheelchair to the crash test sled differs in that WC19 requires the use of a surrogate four-point strap-type tiedown to secure the wheelchair to the crash sled, while ISO 7176-19 permits the use of either a commercial tiedown or a surrogate tiedown during testing.

Another difference between WC19 and ISO 7176-19 relates to wheelchair-anchored belt restraints. "WC19 requires that a wheelchair-anchored lap belt be used instead of a vehicle-anchored lap belt in the frontal impact test. 7176-19 allows a wheelchair to provide for, and be crash tested with, a wheelchair-anchored lap belt, or even wheelchair-anchored lap and shoulder belts (as does WC19), but it does not require it."²

It should be noted that ISO 7176-19 applies to children and adults with a mass of at least 22 kg (48 lbs.) WC19 applies to wheelchairs designed for children with a mass of 12 kg (26 lbs) or more. A wheelchair that is designed for children under 23 kg must provide a "wheelchair-anchored five-point harness in order to provide smaller children with comparable protection as that achieved by a child restraint system. This means that a wheelchair that is rated for occupants from 15 kg to 50 kg must provide both a five-point harness and a wheelchair-anchored pelvic belt. ISO 7176-19 does not include this requirement."²

There are some other differences related to the geometry and placement of securement points on the wheelchair. In addition, there are differences related to the disclosure of lateral stability and turning radius. Also, there are some differences in performance requirements of the frontal impact sled test.² For example, WC19 specifies that no component or part greater than 150 g should detach from the wheelchair during frontal impact testing, while the limit is 100 g in ISO 7176-19. In addition, WC19 addresses power wheelchairs, specifying that batteries and electronic components must remain attached or tethered to the battery compartment, while ISO 7176-19 does not address power mobility specifically.²

It is noteworthy that although there are some differences between the standards, "RESNA WC19 (WC19) and ISO 7176-19 were developed together and with significant coordination and correspondence between the Working Group of the RESNA Wheelchair Standards Committee known as the Committee on Wheelchairs and Transportation (COWHAT) and the Working Group 6 of ISO TC73 SC1. In fact, much of the leadership and authorship for the two standards came from the same individuals."²

Although this month's article has been on transit standards for individuals who must use their wheelchair as a seat in a motor vehicle, let's not forget that the "ideal" safety practice for individuals who use wheelchairs is to "transfer into a manufacturer-installed vehicle seat and use the vehicle's crash-tested occupant restraint system"³ (p.5). When an individual must remain seated in her wheelchair during transit, we need to think of the safety standards related to the design and testing of the wheelchair – whether we are looking at RESNA WC19 or ISO 7176-19.

References

1. University of Michigan Transportation Research Institute. (Feb. 2016) Crash Tested Product Lists. Wheelchairs. Retrieved from https://wc-transportation-safety.umtri.umich.edu/.
2. University of Michigan Transportation Research Institute. Wheelchair Transportation Safety. Frequently Asked Questions. Retrieved from http://wc-transportation-safety.umtri.umich.edu/faqs
3. RESNA. (n.d.) RENSA's Position on Wheelchairs Used as Seats in Motor Vehicles. Retrieved from http://www.resna.org