Companies wishing to sell medical electronic equipment or systems in Europe must first grasp the changing regulatory requirements they have to fulfill. All such products sold in the European market must comply with requirements of the so-called new approach directives that cover product safety, EMC issues, and products regarded as telecommunications devices. Safety issues, including risk analysis, are treated in the Medical Devices Directive (MDD) 93/42/EEC and the relevant safety standards. They are not of interest for the purposes of this article.

The authors here focus on the complex requirements of current EMC and telecommunications directives, outlining their development and discussing possible sources of confusion arising as each set of requirements undergoes revision.

EMC Requirements

Background. Since June 1998, all medical devices have been required to comply with the MDD. With respect to EMC, EN 60601-1-2:93 is the related standard. EN 60601-1-2 is identical with IEC 60601-1-2 and is the collateral standard to the IEC 60601-1, which is the general safety standard for medical electrical equipment. IEC 60601-1-2 was published in April 1993 with the title "Medical Electrical Equipment: Part 1: General Requirements for Safety. 2: Collateral Standard: Electromagnetic Compatibility—Requirements and Tests." In November 1993, EN 60601-1-2 was published in Europe.

The collateral standard EN 60601-1-2:93 contains emission and immunity requirements. The emission test referred to is specified in EN 55011 (CISPR 11) Group I or II, Class A or B. To satisfy immunity requirements, the following so-called basic standards (the old IEC 801 series on "Industrial, Scientific, and Medical Radio-Frequency Equipment—Electromagnetic Disturbance Characteristics") were to be fulfilled:

At the time the collateral standard was developed, the basic standards were under revision. Now, the relevant new publication of these standards must be used—EN 61000-4-3 and EN 61000-4-5—instead of the IEC 801 series. For ESD and EFT, IEC 801-2 and IEC 801-4, respectively, must be used.

These tests described in EN 60601-1-2:93 are well-known to most medical device manufacturers and therefore are not discussed further here.

Revision of EN 60601-1-2. At this time, Working Group 13 of IEC Technical Committee 62 is working on a new edition of EN 60601-1-2. The development of new basic standards and of other standards like EN 55011 has made a second edition necessary. The committee's draft document is presently being circulated for review, comments, and voting. Votes are due back to the IEC by July 15, 2000. The new standard is expected to be published around the middle of 2001 and should stipulate a transition period of three to five years.

Some test laboratories, as well as some manufacturers, are already recommending this second edition of EN 60601-1-2. Nevertheless, the new standard is not officially published yet and cannot be used to show compliance with the MDD.

Such farsightedness is a sensible impulse, however. Many medical devices have very long development and life cycles compared to, say, information technology products. It is important for manufacturers of such devices to follow the development and anticipate the future of the applicable standards, particularly if new standards will have a great impact on product design owing to new tests and other requirements. By way of illustration, Table I presents a comparison of the tests referenced by EN 60601-1-2:93 and those called for in the proposed second edition of the standard.

EN 60601-1-2:93 (published May 1993)
Emission:	EN 55011 class A or B EN 55014 for click noise
Immunity:	ESD (IEC 801-2 1991): 3 kV contact, 8 kV air Radiated Field (IEC 61000-4-3): 3 V/m, 80% AM 1 kHz (or special bandpass), special 1 V/m, 26–1000 MHz
	Burst (IEC 801-4): 1 kV, flexible power supply; 2 kV, fixed power supply; 0.5 kV, input/output lines > 3 m
	Surge (IEC 801-5): 1 kV differential mode; 2 kV common mode
IEC 62A/247/CD:3.98 (to be published in mid-2001)
Emission:	EN 55011 privileged class B (only for special units class A) EN 55014 for click noise
Immunity:	ESD (IEC 61000-4-2): 2+4+6 kV contact, 2+4+8 kV air
	Radiated Field (IEC 61000-4-3): 3 V/m, 80–2500 MHz, AM: 80% , 1 kHz or 2 Hz, Modulation Frequency; 10 V/m from 80–2500 MHz for life-supporting systems
	Burst (IEC 61000-4-4): 2 kV, all kinds of power supply; 1 kV, input/output lines > 3 m; patient cables are excluded
	Surge (IEC 61000-4-5): 0.5 kV, 1 kV differential mode; 0.5 kV, 1 kV, 2 kV common mode
	Conducted RF Immunity (IEC 61000-4-6): 3 V, 80% AM, 0.15–80 MHz, 1 kHz or 2 Hz Modulation Frequency; 10 V for life-supporting systems at the ISM frequencies
	Magnetic Fields (IEC 61000-4-8): 50/60 Hz, 10 A/m; special units can have less
	Ac Variations (IEC 61000-4-11): For systems with input power less than 1 kW, voltage test level 0%, 40%, and 70%; duration (periods) 0.5, 5, 25; voltage interruption 5 seconds
	Harmonics (IEC 61000-3-2/3/4/5)
	Failure Criteria: Clinical utility is maintained. Performance criteria and special tables with information for the user must be included.

Besides technical changes, the draft revision of EN 60601-1-2 introduces new specifications of information that the manufacturer would have to provide in documents accompanying the product. The additional information would give the end-user direction in the use or operation of the product pertinent to EMC. The drafters of the revised standard noted that some medical devices cannot fulfill the specified test levels, particularly for immunity. An example is EEGs. In such cases, the manufacturer must demonstrate in the documentation the level at which the product has passed (see Table II). And when a device is operating in an environment with higher-than-average EMC pollution, the user manual must advise the end-user on how to avoid problems. This gives the manufacturer more freedom in specifying the product.

Because the MDD is a vertical directive that incorporates EMC and safety requirements, the horizontal Electromagnetic Compatibility Directive 89/336/EEC and Low Voltage Directive 73/23/EEC are not applicable. This means that it is not compulsory for medical products to show compliance with the essential requirements of the EMC Directive.

Immunity Test	IEC 60601-1-2	Compliance Level	Electromagnetic Environment Guidance
Electrostatic discharge (ESD) (IEC 61000-4-2)	±6 kV contact ±8 kV air		Floors should be wood, concrete, or ceramic tile. If floors are covered with synthetic material, the relative humidity should be at least 30%.
Electrical fast transient/burst (IEC 61000-4-4)	±2 kV for power supply lines±1 kV for input/output lines		Mains power quality should be that of a typical commercial and/or hospital environment.
Surge (IEC 61000-4-5)	±1 kV differential mode±2 kV commonmode		Mains power quality should be that of a typical commercial and/or hospital environment.
Voltage dips, short interruptions, and voltage variations on power supply input lines (IEC 61000-4-11)	<5% Un (>95% drop in Un) for 0.5 cycle,40% Un (60% drop in Un) for 5 cycles70% Un(3% drop in Un)for 25 cycles,<5% Un (>95% drop in Un) for 5 seconds		Mains power quality should be that of a typical of the [EQUIPMENT and/or SYSTEM] requires continued operation during power mains interruptions, it is recommended that the an uninterruptible power supply or a battery.
Power frequency (50/60-Hz) magnetic field (IEC 61000-4-8)	3 A/m		Power frequency magnetic fields should be at levels characteristic of a typical location in a typical commercial and/or hospital environment.
Table II. A sample document of the type required by the proposed second edition of EN 60601-1-2 to be provided with medical electrical equipment sold in Europe. The equipment or system is suitable for use in the specified electromagnetic environment. The purchaser or user should ensure that it is used in an electromagnetic environment as described.

Telecommunications Requirements

The Intentional Radiator. What if a medical electrical product also includes an intentional radiator (radio) or uses telecommunications terminal equipment? In the authors' experience, this is the most complicated aspect of medical equipment approval. Many manufacturers are not sure exactly what an intentional radiator is, nor are they aware that there is no minimum power limit below which requirements would not apply.

In general, an intentional radiator is a transmitter, a receiver, or a transceiver. These products establish a communication link through the air, so that information or data are transferred from one point to another without a wire. Examples are telemetry products, programmable pacemakers, and wireless hearing aids. The European standards and directives mention no minimum or maximum limit regarding the transmitter power of such products. Even if a product's transmitter power is less than 1 µW and the transmission distance is less than 1 cm, the equipment is considered an intentional radiator and must fulfill the requirements discussed here.

The R&TTE Directive. The regulatory telecom requirements are described in the Telecommunications Terminal Equipment (TTE) Directive 91/263/EC, amended by 98/13/EC. This directive will be finally repealed on April 8, 2001. A new horizontal directive, which at the moment is causing a lot of confusion in Europe, replaced the old TTE Directive in April 2000. It is called the Radio and Telecommunications Terminal Equipment (R&TTE) Directive 99/5/EC, and it now controls the conformity assessment procedure and the introduction into the market of all radio and terminal products. Manufacturers are being allowed a transitional period of one year, from April 8, 2000, to April 8, 2001, to effect the switch from applying the TTE Directive to applying the R&TTE Directive.

The R&TTE Directive establishes a regulatory framework for the placement on the market, the free movement, and the putting into service of radio and telecommunications terminal equipment in the European Union. Its Article 1 describes its scope and aim: "Where apparatus as defined in Article 2(a) incorporates, as an integral part, or as an accessory: (a) a medical device within the meaning of Article 1 of Council Directive 93/42/EEC of 14 June 1993 concerning medical devices; or (b) an active implantable medical device within the meaning of Article 1 of Council Directive 90/385/EEC of 20 June 1990 on the approximation of the laws of the Member States relating to active implantable medical devices, the apparatus shall be governed by this Directive, without prejudice to the application of Directives 93/42/EEC and 90/385/EEC to medical devices and active implantable medical devices, respectively."

This is not the place to describe the complexities of this new directive. Suffice it to say that this directive will allow radio and terminal equipment manufacturers following the same rules to bring their products to the European market faster and more easily.

Conclusion

While most electrical equipment manufacturers already have a good understanding of the safety and EMC requirements applicable to their medical products, confusion about the complicated telecommunications requirements causes them a lot of trouble and expensive delays in product development and introduction. They are advised to approach accredited test laboratories to consult about regulatory requirements and product testing. Knowledgeable people are available to lead the manufacturers through the entire approval process.

Dieter Fröhlich is the laboratory manager for MIKES BABT Product Service GmbH (Strasskircher, Germany), as well as the QMS auditor for Annex III and IV according to the TTE Directive and Annex V according to the R&TTE Directive. Harald Buchwald is the manager responsible for medical products, as well as the marketing and training manager at MIKES BABT Product Service GmbH, and he is a member of TC 62A, Working Group 13.