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EMC AND ELECTRICAL SAFETY TESTING OF MEDICAL DEVICES
As part of the new approach to technical harmonization in the European Union, directives have also been established for medical devices. SGS is one of the premiere organizations accredited for the certification of such electro-medical equipment and expects to play a growing role in the field under the terms of the directive.
The Standards
The ISO 13485 standard is issued specifically for medical equipment. It provides the frame of reference for statutory controls, while its counterpart, the IEC 60601-1, is a general standard for electrical medical equipment safety. The guiding principle of these directives is that only zero-risk is acceptable, especially if the device is to touch the human body, in which case even the smallest problem can present a real danger.
IEC 6060-1 is constantly evolving to keep pace with the technological innovations like faster computers and robotic equipment now being introduced into operating rooms and medical facilities. Further, hospitals are coupling devices from various sources more and more, and these combinations must be 100% safe. In response to these developments, a third edition of standard IEC 60601-1 was published, which now includes a risk management assessment.
The requirements for the electrical safety of medical equipment are much more stringent than those for other electrical devices considering that:
- A patient may be connected to several medical devices simultaneously
- A patient may be connected to electronic circuitry
- A device may directly contact internal tissue, which can easily conduct electricity
The standard has both mechanical and electrical requirements intended to reduce the electrical hazards under both normal and single fault conditions.
The EMC part is considered a safety issue for medical equipment and is verified with the IEC 60601-1-2 as a 'pointer' standard, referring to CISPR 11 for emissions and various IEC 61000-4-X standards for immunity. These standards are basically test methods for various categories of immunity. IEC 60601-1-2 supplies the test levels and defines the pass/fail criteria.
Risk Management
Over the past 10 years, medical science has advanced significantly. The associated equipment is becoming more and more sophisticated, and the electrical risks involved must be completely under control. Such issues can result directly from medical devices as well as the installations to which they are connected. For the safety of employees, visitors and especially patients, it is vital to reduce the associated risks as much as possible. For this, there are 3 basic objectives: safety of equipment, safety of installation, and safety of application.
How to Guarantee these Objectives:
- Medical equipment and electro-medical installations are tested by organizations that are accredited specifically for the certification of medical devices
- Installation equipment is also tested by accredited bodies, such as SGS
Mandatory certification
The directives also specify conditions to be met before permission is granted to apply the CE marking and cover all medical devices and accessories. Manufacturers are obliged to certify their products and their production systems, depending on the class to which they belong. Medical equipment is divided into classes based on the risks posed to patients. Class I products do not have to be certified because they do not contain a measurement function or are not sterile. However, when a product must be sterile, SGS can certify the sterilization process. If it contains a measurement instrument, SGS can verify its accuracy and its algorithms.
Find more information on CE marking at medical devices.
There are 3 directives concerning CE marking and apply to all medical equipment and accessories:
- Active Implantable Medical Devices (AIMD: 90/385/EE)
- Medical Devices (93/42/EEC)
- In Vitro Diagnostic Medical Devices (98/79/EC)
These directives divide the medical devices into 4 groups based on the risk posed to the human body:
- Class I for low-risk devices*
- Class IIa for medium-risk devices
- Class IIb for medium-risk devices
- Class III for high-risk devices
*Class I products do not have to be certified unless they contain a measurement function or must be sterile, in which case SGS can provide the required certification.
The 18 criteria used to determine the risk involved to the human body are based on the three following principles:
- The duration of contact between the device and the patient
- The degree and manner of the device penetrating the human body
- The degree of the device's impact on the human anatomy
Furthermore, there are also a number of general and specific requirements a medical device must comply with to achieve CE marking, regardless of classification.
Generally, it is assumed that the manufacturer's quality system will ensure that the design and/or manufacturing of a medical device is compliant with the requirements of the directives. However, under the directive, a manufacturer’s responsibility does not cease after distribution. Producers are also obligated to systematically monitor their products once they reach the market to ensure their continued safe and reliable performance.
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