For over 40 years, the IEC 60601 series of technical standards has set requirements for the safety and essential performance of medical electrical equipment. It is a widely accepted benchmark for medical electrical equipment and compliance has become a requirement for the commercialization of electrical medical equipment in many countries.
National deviations based on the IEC specifications, such as UL or AAMI for the USA, include country-specific requirements while European EN and Canadian CSA versions are identical to the IEC standard.
While power supplies are not medical devices as such and are therefore not covered directly by the IEC 60606-1 standard, they are integral to the design and operation of medical equipment.
IEC 60601-1 is the general standard, which is supported by several collateral standards numbered 60601-1-X, which define the requirements for certain aspects of safety and performance, such as electromagnetic compatibility (IEC 60601-1-2) or protection for diagnostic use of X-rays (IEC 60601-1-3).
The 2nd Edition of IEC 60601 introduced the Type B, Type BF and Type CF classifications of the applied parts of medical equipment with criteria for applicable levels of clearance, creepage, insulation, isolation and leakage.
The 3rd Edition of IEC 60601-1 increased the emphasis on risk management and added the concept of essential performance while also separating patient protection and operator protection with the acronyms MOPP (means of patient protection) and MOOP (means of operator protection).
While the 3rd Edition standard requirements are based on the purpose of the equipment, the 4th edition of IEC 60601-1 brings in the concept of ‘intended use environments’ to address the growing usage of medical-grade equipment outside of hospitals or professional healthcare facilities to include home use.
The original compliance date of April 2017 was extended by both the FDA and the EU to December 31, 2018.
Environments outside professional healthcare facilities may have reduced control of electromagnetic (EM) disturbances and there are increased contributors to the EM environment that can have detrimental effects on medical devices. The changes also align more with the IEC60601-1 safety standard emphasis on risk management. The intended use environments are:
- Professional Healthcare Facilities including hospitals and clinics
- Home Healthcare covers homes and other public spaces
- ‘Special’ Environments includes military installations, industrial environments or where high power medical equipment is in use, such as radiotherapy devices
Risk Management File
The new 4th Edition EMC standard better harmonizes with the risk concepts and basic safety. Life-support equipment is no longer referenced; rather, emphasis is made on the risk management file (RMF). It requires clear pass/fail criteria prior to testing, which is linked to the essential performance and basic safety outlined in the RMF. Product manufacturers will be required to submit a test plan and the risk analysis document before testing. There are increased test levels for the immunity requirements.
There are also new immunity requirements that take into consideration the effects from RF wireless communications equipment. These are not all encompassing, as the medical device manufacturers need to take into account other possible sources of interference that may affect their equipment.
ESD Immunity Test Level Changes are Significant
The most notable changes to the immunity standard are the increased electrostatic discharge (ESD) level, increased from 6KV/8KV to 8KV/15KV, contact and air discharge respectively, radiated RFE fields and proximity fields from RF wireless communication equipment. Although there are other immunity requirements that have changed and increased in level for the most part, the other changes have not been as challenging to mitigate, at least in terms of the AC-DC power supply’s ability to aid in complying with the new requirement.
A more detailed comparison between the 3rd and 4th Edition immunity test requirements is below: