What is the scope of the requirements in the wheelchair seating standards (RESNA WC20 and ISO-16840-4)?

The primary focus of these standards is to provide a means for evaluating the dynamic crashworthiness of after-market wheelchair seating systems independent of testing the seating system on a wide range of commercial wheelchair frames. The standards specify a surrogate wheelchair frame/base (SWCF or SWCB) to which the seating system can be attached and dynamically tested on an impact sled in conditions that represent worst-case loading conditions on a range of wheelchair frames. In addition, there is a test method that allows the seating system to be rated with regard to allowing proper placement and fit of vehicle-anchored belt restraints to the wheelchair user.

When a seating system is dynamically tested on the SWCF in a 30-mph frontal sled test, the primary performance criteria in WC20 and ISO-CD16840-4 standard are: 

  • that the seating system, including seat and back support, offer effective vertical and horizontal support for the crash dummy so that the dummy is in the wheelchair in a seated posture at the end of the test,
  • that primary support components or structures do not show visible signs of failure that prevent them from supporting the mass of the ATD (ISO), or completely fail (WC20) at the end of the test,
  • that all seat and back support attachment hardware remains attached to the wheelchair and seating system,
  • that no parts of the seating system with a mass greater than 100 g (ISO) or 150 g (WC20) break loose, and
  • that there are no sharp edges on the seating system after the test.