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IEC 60601-1, 2005: A Revolutionary Standard, Part 1

Originally Published MDDI February 2005

Originally Published MDDI February 2005

Regulatory Outlook

IEC 60601-1, 2005: A Revolutionary Standard, Part 1

The third edition of the standard is a more-comprehensive, better-organized document. But will you be prepared for all the changes?


Mike W. Schmidt
Strategic Device Compliance Services

Mike W. Schmidt

In all its incarnations, IEC 60601-1 has played an important part in ensuring the safety of electrically operated medical devices and, therefore, in complying with medical device regulations.1 The standard was originally developed as German National Standard VDE 0750, and compliance was required for medical electrical equipment sold in that country.2 The standard then became a European Norm (EN 60601-1) and, after that, an international standard published by the International Electrotechnical Commission (IEC) as IEC 60601-1.3, 1 As the standard evolved, it continued to play a critical role in demonstrating compliance with medical device regulations in Europe as a harmonized European norm. This article presents a historical overview of IEC 60601-1 as well as the key changes that will be included in the third edition of the standard.

In 1998, when FDA launched its standards recognition program in the United States, the second edition of IEC 60601-1 was one of the first standards listed. IEC/EN 60601-1 will take the next leap in its evolution when the third edition of the standard is published in August 2005. Those who haven't followed the development of the third edition of 60601-1 are likely to be surprised by the new standard. The new edition introduces a dramatic shift in the philosophy behind device safety standards. It combines product requirements (similar to those in the second edition) with process requirements (in the form of risk management) into a single document. Some of the significant new requirements will be discussed in a future issue, along with the compliance options that have been added.

The third edition of IEC/EN 60601-1 also introduces the concept of essential performance. Essential performance refers to those characteristics of a device's operation that can directly affect the safety of the patient, the user, or others. As soon as the new standard is published, it will be harmonized in Europe and added to FDA's list of recognized standards, replacing its predecessor. In addition, national standards bodies in countries such as Australia, Canada, Japan, and the United States, where national standards had been based on the second edition of IEC 60601-1, will be updating those documents to reflect the significant changes implemented in the third edition. A compliance management tool to help manufacturers understand the changes between IEC 60601-1, 2nd edition, and the third edition is available on-line at www.devicecompliance.com.

In the United States, the current standard, Underwriters Laboratories (UL) 2601-1, combines the requirements of the second edition of IEC 60601-1 with approximately 32 pages of U.S. deviations.4 However, it will be replaced by AAMI/ANSI 60601-1 by 2006.5 This new U.S. standard will incorporate all of the requirements of the third edition of 60601-1 but will include only two pages of U.S. deviations. The significant reduction in the number of U.S. deviations results from a decision by the Association for the Advancement of Medical Instrumentation (AAMI) Electrical Safety Committee. The committee opted to include only requirements from the National Fire Protection Association 1999 standard and the National Electric Code related specifically to medical devices.

Transitioning to the Third Edition

The significant changes being introduced in the third edition of IEC 60601-1, as well as the European and national standards based on it, consistently raise one question: “How long will the transition period be?” Technically, all of the standards based on IEC 60601-1 are voluntary, and this makes the issue of transition moot. Transition periods for new standards essentially recognize that it would be impossible for manufacturers to instantly shift from an old standard to its successor for all new and existing designs. Typically, transitions set a time limit after a new standard's publication when new products can no longer be certified to the old standard. Transitions also define how long existing products may continue to claim compliance with the old requirements before they must be recertified to the new standard. In Europe, the significant role standards play in ensuring compliance with the Medical Devices Directive (MDD) has resulted in a standardized period for transitions (typically three years).6 IEC, however, has no set policy. In most cases, it withdraws the old standard when the new publication is issued. In the United States, the standards development organization (SDO) that published the standard determines how to transition between revisions. For example, UL has repeatedly changed its policy on when manufacturers must switch from UL 544 to UL 2601-1.7, 4 And there are still products on the market certified to UL 544.

Cooperative discussions within IEC and between IEC and the European SDO, CENELEC, began during the last year. The United States and most other countries that publish their own national versions of IEC 60601-1 are heavily involved in the work of IEC and specifically in the development of the third edition. So it is likely that all will adopt whatever transition is agreed to between IEC and CENELEC. Currently, the most commonly discussed time frame is three years.

However, IEC 60601-1 is not intended to be used alone. The standard addresses general issues of safety that are applicable to most electrically operated medical devices. In addition to applying this standard, manufacturers must also apply relevant collateral standards addressing issues such as electromagnetic compatibility and programmable devices and systems.

In addition, manufacturers should apply any applicable particular device-specific standards. Collateral standards in the 60601 family are numbered using the following convention: 60601-1-x, where x indicates the specific document. Particular standards are numbered 60601-2-x, where x indicates the specific particular standard. Currently, there are nearly 60 published device-specific standards. Unfortunately, the collateral and particular standards that were written for use with the second edition of 60601-1 will be, for the most part, unusable with the third edition. Logistically, it was impossible to modify these collateral and particular standards concurrent with the writing of the third edition. Although the project to update the general standard has been active since 1996, revision of the collateral and particular standards started in 2004 and should be completed in late 2007. Work on the device-specific standards also began in 2004. Manufacturers that want to have input into the standards' new content should review and comment on the drafts as they are circulated by their national committees. For those in the United States, AAMI manages the comment and voting process and can be contacted through its Web site at www.aami.org.

New Collateral Standards

During the development of the new edition of IEC 60601-1, it became obvious that at least two additional collateral standards were needed to support the standard. Subcommittee 62A was responsible for producing the 60601 general standard, including collateral standards. However, in discussing the need for these standards, the committee realized that the gap they had identified for the third edition existed in the second (current) edition as well. But while the use of collateral standards under the second edition was not explicitly required, the third edition will require these documents to be applied for manufacturers to claim compliance with IEC 60601-1.

The need for the two new collateral standards was caused by the proliferation of particular standards for medical electrical equipment requiring alarms. In many cases, these standards directly conflicted with each other. Manufacturers of devices covered by such standards in different markets faced regulatory nightmares. In addition, clinicians and regulators were becoming increasingly concerned that the conflicts in alarm requirements were confusing to the users of the equipment. In response, IEC 60601-1-8 was published in 2003 for use with the then-current version of IEC 60601-1.8 The group that published that standard for use with the second edition will revise the document for use with the third edition in time for its publication in 2005.

Although this collateral standard does not set inflexible requirements for alarms, it does establish basic groupings of alarm types (high, medium, and low priority) and describes the basic characteristics for each. The standard also addresses issues associated with synthetic voice alarms and other new types of alarms in addition to traditional audible and visual ones.

In addition to the alarms collateral standard, the committee identified the need for a standard addressing human factors design and user error. FDA and several other regulatory bodies worldwide have recognized that many injuries from medical equipment arose from user confusion. The result of this recognition was the creation of IEC 60601-1-6, which was published for use with the second edition of IEC 60601-1.9

In addition to establishing basic requirements for developing user interfaces on medical devices, this standard brought clarity to the principle of foreseeable misuse. The term was introduced in Europe's MDD but had not been defined until publication of 60601-1-6. In essence, the collateral standard states that anything users might do, based on human factors evaluations, or anything they have done, based on the history of similar devices, constitutes foreseeable misuse. The standard further states that if the manufacturer applies the principles of human factors design and, where such design features do not eliminate the risk, warns the user through labeling and accompanying documents, the foreseeable misuse in question becomes abuse. According to 60601-1-6, abuse of the equipment by the user is not the manufacturer's responsibility.

Like 60601-1-8, IEC 60601-1-6 is being revised for use with the third edition of the general standard and should be published in 2005. U.S. and EU regulators, as well as those in most other major markets, have recognized these standards for use with 60601-1, 2nd edition and plan to do so with the versions based on the third edition.

How Has the Third Edition Changed?

The new IEC 60601-1 is nearly 100 pages longer than its predecessor. The increased length was driven primarily by three factors: new requirements, more options in complying with the requirements, and an extensive rationale (found in Annex A).
The philosophy behind the new requirements of the third edition of 60601-1 can be found in an IEC Technical Report published in 1994. That document, IEC 60513, is available from IEC.10 The technical report instructs standards writers to generate requirements based on the following principles:

• Identify the specific hazard to be addressed by each requirement.
• Identify the acceptable risk level associated with each hazard.
• Provide, where possible, an objective test that determines whether the acceptable risk level has been achieved.
• Avoid requirements, whenever possible, that define how to achieve an acceptable risk level (i.e., avoid design solutions).
• Encourage the use of risk analysis and risk reduction techniques to resolve issues not specifically addressed in the standard and to demonstrate alternative solutions to risk reduction.

By applying these underlying principles, the new standard offers an unprecedented level of guidance to designers who fully understand its requirements. However, the importance of the expanded rationale's role in achieving that understanding should not be dismissed.

The rationale has always been an important and underused resource in all standards but is especially critical when applying 60601-1. In the second edition, clause 3.4 states, “Equipment or parts thereof having forms of construction different from those detailed in this Standard, shall be accepted if it can be demonstrated that an equivalent degree of safety is obtained.” However, to take advantage of this flexibility, one must first understand the thought process behind the requirements. In some cases, the intent of the writers may be intuitive, but for most, the best source for this information is the rationale. In the third edition, the information provided in the rationale becomes even more critical to applying the standard correctly. Demonstrating equivalent safety requires analysis as part of the risk management process. The information in the rationale is the starting point for that evaluation.

In addition to the expanded size of the new edition, the clause numbering has been changed radically to comply with current IEC rules on the format of standards. Although the renumbered clauses may be disconcerting for those who have been using the second edition for some time, the changes significantly improve the new standard's readability and usability. It is better organized and has fewer cross-references, reducing the need to read several parts of the document to understand one requirement. The clauses are now organized as follows:

• Clause 3 contains definitions.
• Clause 4 addresses the general
requirements.
• Clause 5 identifies test conditions for applying the requirements of the standard.
• Clause 6 contains requirements related to classification.
• Clause 7 includes the requirements for information provided to the user, such as labeling, instructions for use, and technical descriptions or service manuals.
• Clause 8 addresses electrical hazards.
• Clause 9 addresses mechanical hazards.
• Clause 10 addresses issues related to physiological effects from
radiation.
• Clause 11 identifies hazards related to heat and fire.
• Clause 12 addresses accuracy of controls and possible hazardous output.
• Clause 13 contains fault conditions that must be addressed.
• Clause 14 incorporates requirements for programmable electrical medical systems (formerly the collateral standard 60601-1-4).
• Clause 15 defines general issues of construction of the equipment.
• Clause 16 incorporates the content of the 60601-1-1 collateral standard for systems.
• Clause 17 contains references to the 60601-1-2 electromagnetic compatibility collateral standard.

Conclusion

Particular standards (60601-2-x) use the same clause numbering as the general standard. So it is easy to see how using existing particular standards with the new 60601-1 would be difficult based only on the restructuring of clause numbers in the standard. Therefore, most certification bodies and regulators will delay requiring that products be certified to the third edition until the new particular standards are published in early 2008. However, significant changes have been made to specific requirements and general philosophy in the new 60601. Such changes suggest that manufacturers that want to avoid confusion, unnecessary costs, and delays should start becoming familiar with the third edition as soon as possible.

References

1. IEC 60601-1, “Medical Electrical Equipment—Part 1: General Requirements for Safety,” 2nd ed. (Geneva: International Electrotechnical Committee, 1988).
2. VDE 0750, “Medical Electrical Equipment” (Frankfurt, Germany: The Association for Electrical, Electronic, and Information Technologies, 2004).
3. EN 60601-1, “Medical Electrical Equipment—Part 1: General Requirements for Safety” (Brussels: European Committee for Electrotechnical Standardization, 1988).
4. UL 2601-1, “Medical Electric Equipment, Part 1: General Requirements” (Northbrook, IL: Underwriters Laboratories, 1997).
5. AAMI/CDV-2 60601-1, “Medical Electrical Equipment—Part 1: General Requirements for Basic Safety and Essential Performance,” draft (Arlington, VA: The Association for the Advancement of Medical Instrumentation, 2004).
6. Council Directive 93/42/EEC of 14 June 1993 Concerning Medical Devices, Official Journal of the European Communities 36 (July 12, 1993): 1.
7. UL 544, “Medical and Dental Equipment” (Northbrook, IL: Underwriters Laboratories, 1985).
8. IEC 60601-1-8, “Collateral Standard: Alarms Systems—General Requirements, Tests, and Guidance for Alarm Systems in Medical Electrical Equipment and Medical Electrical Systems” (Geneva: International Electrotechnical Committee, 2003).
9. IEC 60601-1-6, “Collateral Standard: Usability” (Geneva: International Electrotechnical Committee, 2004).
10. IEC 60513, “Fundamental Aspects of Safety Standards for Medical Equipment” (Geneva: International Electrotechnical Committee, 1994).

Copyright ©2005 Medical Device & Diagnostic Industry

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