It wasn’t long ago that EMC Testing and Risk Management wouldn’t have appeared in the same sentence. Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) testing has normally been performed to meet the criterion established for a desired label. Once compliance testing has been passed, it’s off to market.
Medical Equipment Safety Concerns
A modern medical facility is packed with electronic equipment. Much of this equipment is directly involved with safety critical tasks involving life support, monitoring patient vital signs, and alerting personnel of critical situations. Other equipment in the environment such as cell phones, microwave ovens, and radio devices can interfere with the normal function of safety critical equipment resulting in unknown or behaviors.
A list of EMI disturbances in medical devices was released in Interference Technology 2020 Medical EMC Guide. They include:
- An ambulance radio interfering with a monitor/defibrillator resulting in death.
- Failure of renal dialysis equipment due to power input susceptibility.
- Pacemaker compatibility issues when exposed to 13.56 MHz RFID readers.
Risk Management and IEC 60601-1-2
As a result of incidents of medical equipment susceptibility standard such as IEC 60601-1-2 now require a risk assessment be performed before testing to determine immunity test levels and pass fail criteria. This analysis must be conducted by the manufacturer. It should define the essential performance each essential function of the device to be tested against the factors likely to be encountered in the intended environment. These factors include radiated energy sources, conducted sources, electrostatic discharge, and power fluctuations and disturbances.
After this assessment is performed a list of relevant immunity test methods can be selected at realistic levels can be documented in a test plan. This test plan, again, is the responsibility of the manufacturer to create.
EMI Risks in Other Applications
Electronics are everywhere. When they are capable of producing safety risks, EMI testing beyond demonstration of compliance is a consideration. The braking problems that plagued Toyota in 2010 were caused from EMI. As vehicles become more densely populated with electronic devices the ability of all devices to coexist becomes more questionable. Additionally portable devices such as cell phones contribute to a more complex radio environment.
EMI Standard Development
As mentioned at the beginning of this article EMC testing does not typically include risk management. Most testing is performed to exacting standards that set a fixed level for compliance.
Because standards lag behind the technologies they seek to regulate it is likely to be sometime until risk assessment is fully embraced by these standards. In time, however, EMC will have to be embraced as an essential part of quality management to ensure the basic safety of the devices we rely on everyday.
CVG Strategy EMI Consultants
CVG Strategy EMI/EMC consultants can provide susceptibility analysis and recommend appropriate test methodologies for verification a product’s ability to perform as specified in today’s congested spectrum.