Medical device test – electromagnetic compatibility
Electromagnetic compatibility (EMC) is the modern concept that combines such popular electromagnetic phenomena as radio interference, effects on the network, overvoltage, voltage fluctuations in the network, electromagnetic influences, grounding effects, etc.
In recent decades, there has been a rapid growth in the development of medical electrical products and systems. EMC for medical devices (MD) can be defined as “the ability of a MD to function satisfactorily in its electromagnetic environment without affecting on this environment and without creating unacceptable electromagnetic interference to other technical equipment”.
There are over 50 standards and test methods in Russia that regulate the scope of modern requirements for medical devices to ensure electromagnetic compatibility. This list includes:
- first edition of IEC 60601-1 – the original safety standard for electrical MD;
- series of additional standards IEC 60601-1-XX for medical electrical products;
- series of private standards IEC 60601-2-XX for medical electrical products;
- series of standards IEC 60601-3-XX for functional characteristics of electrical medical devices of certain types.
The main standard governing the EMC requirements for medical devices is GOST R IEC 60601-1-2-2014 “Medical electrical equipment. Part 1-2. General requirements for basic safety and essential performance. Collateral standard. Electromagnetic compatibility. Requirements and tests”.
It is practically impossible to carry out tests according to the procedure for checking compliance with EMC standards without a specialized testing laboratory (TL). The TL must be located in a radio-free environment, away from base stations and any radio wave contamination.
The room for the test must be equipped with special adaptions wall covering the ceiling and floor that absorb electromagnetic radiation (anechoic champers).
Figure 1.1. – Exterior of the EMC test room.
During the EMC test, the following parameters are checked:
- Electromagnetic emission:
- Protection of radio services;
- Protection of other products from the low-frequency magnetic fields;
- Protection of electrical distribution networks.
- Electrostatic discharges;
- Radiated radio frequency electromagnetic fields;
- Nanosecond impulse noise;
- High energy microsecond impulse noise;
- Conducted interference inducted by radio frequency electromagnetic fields;
- Dips, short interruptions and changes in input power lines;
- Magnetic fields.
- Identification of labels and documentation
- Verification of operational documentation
Example of equipment used in EMC tests:
|· Generator of electrical discharges|
|· Pulse generators|
|· Power amplifiers|
|· Equivalents of power supply and impedance|
|· Measuring receiver|
|· Measuring and emitting antennas|
|· Equipment for testing the resistance to magnetic field|
|· Current collectors|
Medical devices or systems must provide the required performance and remain safe during testing.
The list of deviations from the required quality of functioning that are unacceptable:
- Change settings;
- The presence of malfunction established by the manufacturer in the operational documentation;
- Change of working mode;
- Termination (shutdown) or suspension execution of any function in progress;
- Initiate the execution of any unintended function, including unintended and uncontrolled movements.
EMC tests are part of technical tests during MD registration. The test procedure is regulated by Order of the Ministry of Health of the Russian Federation dated January 9, 2014 №2n “On approval of the Procedure for assessing the conformity of medical devices in the form of technical tests, toxicological studies, clinical trials for the purpose of state registration of medical devices”.
The main notes on EMC in registering MD in accordance with Decree of the Government of the Russian Federation dated December 27, 2012 №1416 “On Approval of the Rules for State Registration of medical Devices” are:
- Labeling of medical devices does not allow to uniquely identify it to the Registration Certificate;
- Information on EMC is partially or completely missing in the operating documentation;
- Non-compliance of the content with requirements of the standards;
- Product maintenance information is not provided.
Failure to comply with the EMC requirements of medical devices and systems can lead to irremediable damage to the patient. Obvious examples of products requiring EMC standards are pacemakers, devices for hemodialysis and pulmonary ventilation.
- GOST R IEC 60601-1-2010 Medical electrical equipment. Part 1. General requirements for basic safety and essential performance: approved and put into effect by the Order of the Federal Agency for Technical Regulation and Metrology November 23, 2010 № 492-st: date of introduction 2011-09-01. – URL: http://docs.cntd.ru/document/1200084982 (accessed: 12.10.2020). – Text: electronic (in Russ.)
- GOST R IEC 60601-1-2-2014 Medical electrical equipment. Part 1-2. General requirements for basic safety and essential performance. Collateral standard. Electromagnetic compatibility. Requirements and tests: approved and put into effect by the Order of the Federal Agency for Technical Regulation and Metrology dated February 26, 2014 № 45-st: date of introduction 2015-03-01. – URL: http://docs.cntd.ru/document/1200109335 (accessed: 12.10.2020). – Text: electronic (in Russ.).
- Tihonov D.V. Jelektromagnitnaja sovmestimost’ [Electromagnetic compatibility]/ D.V. Tihonov – Text: electronic // Department of ESVT ELTI – URL: http://relayprotection.pbworks.com/f/ESVT_EMS.pdf (accessed: 13.10.2020) (in Russ.).
- Rybalov A.A. Rekomendacii po vyboru standartov, podderzhivajushhih vazhnejshie principy obespechenija bezopasnosti i jekspluatacionnyh harakteristik peredvizhnyh (podvizhnyh) medicinskih kompleksov [Recommendations for the selection of standards that support the most important principles of ensuring the safety and operational characteristics of mobile (mobile) medical complexes] – URL: https://roszdravnadzor.gov.ru (accessed: 14.10.2020). – Text: electronic (in Russ.).
- Kenneth W. 2017 EMC Fundamentals Guide – Interference Technology Guide Series 2017 Item – URL: https://ru.scribd.com/document/368762124/2017-EMC-Fundamentals-Guide-Low-Res (accessed: 10.10.2020). – Text: electronic (in Russ.).