A Regulatory Review of the EMC Standard for Medical Devices

Leonard Eisner, Robert M. Brown, and Dan Modi

Manufacturers should be prepared to meet tougher requirements now that the second edition of IEC 60601-1-2 is supplanting the first.

Table I. Comparison of immunity tests in the first and second editions of IEC 60601-1-2 (click to enlarge)..

Recently, manufacturers have had two options for showing compliance with the electromagnetic compatibility (EMC) requirements for medical devices sold in the European Union (EU): they could use either EN/IEC 60601-1-2:1993 or EN/IEC 60601-1-2:2001.^1,2 However, the period of overlap between the first (1993) and second (2001) editions of the standard ended November 1, 2004. That is, the convenient transition from applicability of the first edition to replacement by the second edition is now history.

Some manufacturers have not recognized that there will be no grandfathering after November 1 for new equipment evaluated to the first edition of 60601-1-2. The presumption of conformity has ceased. Products that will be CE marked after November 1, 2004, require retesting to the new standard. This article reviews the differences between the first and the second editions of EN 60601-1-2, the regulatory status of the second edition, and the steps manufacturers need to take to bring their product line into agreement with the new standard.

EMC Overview

Table II. Emissions tests in the first and second editions of IEC 60601-1-2 compared (click to enlarge).

EMC signifies the ability of a device to operate harmoniously in its electromagnetic (EM) environment. That is, the device both is compatible with (not susceptible to) its EM environment and does not emit levels of EM energy that cause electromagnetic interference (EMI) in other devices operating in the vicinity.

New communications technology is proliferating today, as evidenced by the many cell phones, personal communications systems, and wireless computer links. At the same time, cutting-edge electronics are being used increasingly in medical products for purposes of speed, automation, and miniaturization. The amount of electromedical equipment to be found in a typical hospital operating room, surgicenter, or doctor’s office also is increasing rapidly; devices often are stacked on top of each other. Hence, it is not surprising that Standards Committee 62A of the International Electrotechnical Commission decided to revise the 1993 edition of IEC 60601-1-2. The second edition was a major rewriting of the standard that is having a profound effect on the regulatory compliance of electromedical products.

EMC compliance is an important aspect of the safety and efficacy (or safety and performance) evaluation of electromedical devices conducted by regulatory bodies. Besides receiving emphasis in the EU, product EMC is also required by, and reviewed for, all of the other regulated medical equipment markets, including Canada, Australia, and Japan.

In the United States, the Food and Drug Administration (FDA) requires EMC review for all its market clearances. The Electromagnetic Compatibility Working Group of FDA’s Center for Devices and Radiological Health (CDRH) coordinates CDRH activities to ensure medical device EMC. FDA also takes into account EMC in its good manufacturing practices (GMP) inspections, which require FDA investigators to assess a firm’s EMC activities while conducting an overall inspection of its quality system and GMPs. Almost all of the regulated markets refer to IEC 60601-1-2 as a method of showing the product’s safety with respect to EMC.

Regulatory Status of EN/IEC 60601-1-2:2001

The various regulated countries and regions have taken several different approaches to effecting the transition from recognizing the first edition of the EMC standard for medical devices to requiring compliance with the provisions of the second.

Table III. Example guidance and manufacturer’s declaration regarding a product’s electromagnetic emissions to IEC 60601-1-2, 2nd ed (click to enlarge).

European Union. The EN 60601-1-2 standard (identical to IEC 60601-1-2) is listed as the harmonized standard under the Medical Devices Directive (MDD; 93/42/EEC).³ The first edition (EN 60601-1-2:1993) lost its harmonized-standard status on November 1, 2004—in other words, stopped providing the presumption of conformity to the essential requirements of the MDD—and the second edition (EN 60601-1-2:2001) became the new harmonized standard.⁴ Compliance with the latter standard is necessary to show compliance with the MDD and to CE mark a product.

United States. FDA also lists IEC 60601-1-2 as the so-called consensus standard. On June 1, 2001, the agency adopted the second edition, superseding its recognition of the first. However, FDA acknowledged that, since there were new devices currently being tested or that were designed to meet the requirements of the first edition of the standard, it had decided to accept declarations of conformity to either the first or the second edition from January 14, 2002, the effective date of recognition of the second edition, until November 30, 2004. After this transition period, declarations of conformity to only the second edition of the standard are being accepted in support of a premarket submission.

Also, FDA advises manufacturers to review their GMP and quality system documents that reference IEC 60601-1-2:1993 in order to determine whether updates to reference the 2001 version are appropriate or necessary.²

Table IV. Example guidance and manufacturer’s declaration regarding a product’s electromagnetic immunity (except RF immunity) to IEC 60601-1-2, 2nd ed (click to enlarge).

Canada. The Therapeutic Products Directorate (TPD) also has listed the second edition as the recognized standard for Canada. Like FDA, TPD holds that conformance with recognized standards can provide a reasonable assurance of safety and effectiveness for many applicable aspects of a medical device and, in most cases, eliminate the need to review actual test data for those aspects of the device addressed by the standard. The approach to transitioning from the first to the second edition of IEC 60601-1-2 taken by the Canadian agency also is similar to that of its U.S. counterpart.

Japan and Elsewhere. Japan’s Mini-stry of Health & Welfare now recognizes both the first and second editions of IEC 60601-1-2. The transition to recognizing the second edition exclusively is expected to be complete after 2010.

Other regulated markets, such as those in Australia and Korea, also accept compliance with the second edition as compliance with EMC requirements either directly, by quoting it in their own guidance documents, or indirectly, by their reliance on the compliance of the product in the United States or EU. But all of these other markets do not require retesting of already-existing legacy products to the second edition as the EU does. A major change to a product requiring its reregistration obviously could compel compliance with the new edition.

First and Second Editions Compared

Tables I and II list the differences between IEC 60601-1-2:1993 and IEC 60601-1-2:2001 for the immunity and emissions EMC tests, respectively.

The biggest change in the immunity tests is not, however, the difference in the test methods or the test limits, but the acceptance criteria introduced. The second edition expects the manufacturer to identify the essential performance of the product based on its intended use and its risk management profile. When subjected to the immunity tests—that is, when EMI phenomena are imposed on it—the product is expected to continue to exhibit its essential performance. The first edition, on other hand, allowed the product to fail as long as it did so in a safe state.

Table V. Example guidance and manufacturer’s declaration regarding a product’s radio-frequency (RF) immunity to IEC 60601- 1-2, 2nd ed (click to enlarge).

Besides changing test requirements for emissions and immunity tests, the second edition of EN/IEC 60601-1-2 requires that substantial information be provided to the product user that was not required by the first edition. The manufacturer must list the emissions and immunity compliance levels of the unit, and must supply guidance to enable the user to ensure compatibility of the product with its EM environment. Tables III–VI represent one example of required documentation for inclusion in the operator’s manual for a typical electromedical product.

The information to be included in the operator’s manual or service manual (the manufacturer should check with its notified body) is complicated, and its nature is dependent on the type of device, its intended environment, and its classifications, among other factors. The requirements can be confusing and warrant careful attention. A work-aid is available at www.eisnersafety.com/featuredproducts.htm. The tool is useful for manufacturers that are unfamiliar with the requirements.

Strategy for Compliance: Legacy Products

The effective expiration of the applicability of the first edition of IEC 60601-1-2 provides a good opportunity for manufacturers to take stock of their electromedical products and decide which ones are no longer marketworthy in light of their market history. Perhaps a product exhibits susceptibility to the changed EM environment. Or, considering its sales volume, it may not be cost-advantageous to retest a product to the new standards. In cases like these, manufacturers should consider discontinuing the product.

Table VI. Example manufacturer’s guidance document for users regarding the recommended separation distances between portable and mobile RF communications equipment and the manufacturer’s product to IEC 60601-1-2, 2nd ed (click to enlarge).

But if the product has a good market history and a still viable market yet cannot comply with the new standard, the manufacturer has an option. The manufacturer may be able to show that the legacy product continues to comply with the essential requirements of the MDD, and to continue to CE mark the device.

The first step would be to retest the product against the second edition, IEC 60601-1-2:2001, and identify the areas where its emission or immunity levels are short of the required levels specified by the new standard. The manufacturer should consider redesigning the product to meet the areas where the product falls short. However, if that is cost-prohibitive, or does not bring any benefit with reference to the level of risk, the manufacturer may decide to apply the standard in part—including testing up to the levels specified in the first edition.

The manufacturer would then develop the justification that, at those first-edition levels, the product continues to meet the requirements of safety and performance for its intended use and the environment. Such an analysis would be conducted on the basis of risk management principles. In other words, if the product continues to meet the essential requirements, and if the product’s market history (that is, a literature review and its complaint history) supports the risk analysis, the product may continue to be CE marked. Many manufacturers are overlooking this option, and fail to discuss it with their EU notified bodies.

Table VII. A sample list of clinical performance functions that a manufacturer might prepare for the EMC evaluation of a product to IEC 60601-1-2, 2nd ed (click to enlarge).

The United States and Canada would require that legacy products be updated to the second edition only (1) if the product underwent a substantial change making necessary a new submission for premarket clearance (or if postmarket experience showed that the product required a higher level of EMC, in which case it might have to meet levels even higher than those in the second edition), or (2) if the company’s quality system required that products be updated with the change in the standard. As mentioned earlier, other regulated markets do not require transition to the new edition for legacy products.

Strategy for Compliance: New Products

Manufacturers will have to design new products so as to meet the substantially higher EMC requirements of IEC 60601-1-2:2001. The design of electromedical products will require additional planning and a team effort involving members of the R&D and regulatory staff, among others.
Manufacturers will also have to perform effective risk management. To ensure a proper EMC evaluation, and to assist the in-house or third-party test lab, they should identify the following items expected by the standard:
• Intended use, characteristics, and properties of the device.
• Functions of the product (a table listing all clinical performance functions as schematized in Table VII).
• Modes and configurations of the device (a table listing these as schematized in Table VIII).
• Essential performance (again, see Table VII).
• Test modes (a table listing these as schematized in Table IX).
• Residual risk (evaluation for the operator’s manual as in Tables III–VI).

Table VIII. A sample list of modes and configurations that a manufacturer might prepare for the EMC evaluation of a product to IEC 60601-1-2, 2nd ed (click to enlarge).

Generally, the system shall be able to provide essential performance and remain safe. Manufacturers should note the following types of performance degradation, identified in IEC 60601-1-2, clause 36.202.1(j), that shall not be allowed (these apply to each essential performance aspect or function of the system):

• Component failure.
• Changes in programmable parameters.
• Reset to factory defaults or manufacturer’s presets.
• Change of operating mode.
• False alarms.
• Cessation or interruption of any intended operation, even if accompanied by an alarm.
• Initiation of any unintended operation, including unintended or uncontrolled motion, even if accompanied by an alarm.
• Error of a displayed numerical value sufficiently large to affect diagnosis or treatment.
• Noise on a waveform in which the noise is indistinguishable from physiologically produced signals or the noise interferes with interpretation of physiologically produced signals.
• Artifact or distortion in an image in which the artifact is indistinguishable from physiologically produced signals or the distortion interferes with interpretation of physiologically produced signals.
• Failure of the automatic diagnosis or treatment equipment or system to diagnose or treat, even if accompanied by an alarm.

Conclusion

Table IX. A sample list of test modes for immunity testing that a manufacturer might prepare for the EMC evaluation of a product to IEC 60601-1-2, 2nd ed (click to enlarge).

In summary, the second edition of EN/IEC 60601-1-2 presents substantial changes in the EMC requirements for medical devices. It has been widely adopted by global regulatory bodies and is expected to be the standard for EMC regulatory compliance. Manufacturers will have to develop an effective strategy for achieving compliance with both their legacy products and their new products. To effectively meet the challenges of EN/IEC 60601-1-2:2001, manufacturers will have to design in the EMC performance requirements. This will require effective use of resources, internal and perhaps external, which manufacturers should manage carefully in order to avoid falling behind on other projects. Failure to plan for the new EMC requirements could critically affect business time-to-market. On the other hand, a good strategy could provide a competitive advantage.

References

1. IEC 60601-1-2:1993, “Medical Electrical Equipment—Part 1: General Requirements for Safety—Section 2: Collateral Standard—
Electromagnetic Compatibility—Requirements and Tests” (Geneva: International Electrotechnical Commission, 1993).
2. IEC 60601-1-2:2001, “Medical Electrical Equipment—Part 1: General Requirements for Safety—Section 2: Collateral Standard—Electromagnetic Compatibility—Requirements and Tests” (Geneva: International Electrotechnical Commission, 2001).
3. The EN 60601-1-2 standard (identical to IEC 60601-1-2) is listed as the harmonized standard under the Medical Devices Directive (MDD; 93/42/EEC).
4. The first edition (EN 60601-1-2:1993) lost its harmonized-standard status on November 1, 2004—in other words, stopped providing the presumption of conformity to the essential requirements of the MDD—and the second edition (EN 60601-1-2:2001) became the new harmonized standard. 

Leonard Eisner, PE, is head of Eisner Safety Consultants (Portland, OR), a firm that specializes in helping medical device manufacturers through the regulatory process. He is a member of the US TAG for TC 62 and SC 62A. He can be contacted via e-mail at leo@eisnersafety.com. Robert M. Brown is director of electrical safety test products for QuadTech (Maynard, MA), and Dan Modi is assistant director at Alcon Research Inc. (Irvine, CA).