Electromagnetic Compatibility Testing and Safety Requirements for Powered Wheelchairs
This guidance addresses the electromagnetic compatibility (EMC) concerns for powered wheelchairs, specifically focusing on uncontrolled movements when exposed to radio frequencies (RF) and microwave radiation.
What You Need to Know? 👇
What electromagnetic interference issues affect powered wheelchairs?
Powered wheelchairs can experience uncontrolled movement when exposed to radio frequency (RF) and microwave radiation from sources like police radios, fire department radios, and walkie-talkies operating at various frequencies.
At what field strength do powered wheelchairs become susceptible to RF interference?
FDA testing found that consistent wheel movement could be induced with field strengths of about 10 V/m, which can occur within three feet of medium power hand-held radios operating at 450 MHz.
What frequency range poses risks to powered wheelchair electromagnetic compatibility?
FDA tests examined radio frequency interference susceptibility from 1 MHz to 1000 MHz, finding wheelchairs vulnerable across this wide spectrum of RF and microwave frequencies that can activate wheels and brakes.
What safety risks does electromagnetic interference pose to wheelchair users?
EMC-induced brake release and uncontrolled wheelchair movement creates potential injury risks for users, as the device may move unexpectedly when exposed to common radio frequency sources in the environment.
What regulatory response is required from powered wheelchair manufacturers regarding EMC issues?
Manufacturers must respond within 20 working days, providing incident reports, complaints, studies, and technical information on how they’ve addressed or plan to prevent unintended movement from radio interference.
Which common devices can cause interference with powered wheelchairs?
Police radios, fire department radios, security guard walkie-talkies, and other medium power hand-held radio devices operating around 450 MHz can cause interference when within approximately three feet of the wheelchair.
What You Need to Do 👇
Recommended Actions
- Review and document any existing incident reports or complaints related to EMC interference
- Conduct EMC testing across the specified frequency range (1 MHz to 1000 MHz)
- Evaluate wheelchair performance near common RF sources like police/security radios
- Implement technical solutions to prevent unintended movement due to RF interference
- Develop and submit response to FDA within 20 working days including:
- Documentation of any known incidents
- Technical information on EMC solutions
- Action plan for preventing unintended movement
- Consider implementing EMC shielding or other protective measures
- Update risk management documentation to include EMC-related hazards
Key Considerations
Non-clinical testing
- EMC testing across frequencies from 1 MHz to 1000 MHz
- Testing for susceptibility to RF and microwave radiation
- Field strength testing at 10 V/m level
- Testing for interference from medium power hand-held “walkie-talkie” type radios at 450 MHz
Safety
- Prevention of unintended wheelchair movement due to RF interference
- Protection against EMC-induced brake release
- Consideration of safety at distances up to 3 feet from RF sources
Other considerations
- Requirement to report incident reports and complaints related to EMC issues
- 20-working-day response timeline for manufacturers
Relevant Guidances đź”—
- Electromagnetic Compatibility for Medical Devices and Accessories: Testing, Documentation, and Labeling Requirements
- Premarket Notification Requirements for Manual and Powered Wheelchairs and Three-Wheeled Vehicles
Related references and norms đź“‚
- IEC 60601-1-2: Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral Standard: Electromagnetic disturbances