Conformity Magazine - September 2008 - (Page 24)

Its 2nd Edition, which will also be a Technical Specification, is close to being finished [10] and has been rewritten using IEC 61508 terminology so that it can be used as the “missing EMC annex” when applying IEC 61508, or standards based upon IEC 61508. However, the IEC medical standards community applied for and received [11] an exemption from the safety pilot function of IEC 61508, so the risk management standard referenced by medical standards will continue to be ISO 14971 instead. This is a good safety standard in its own right, and employs many of the safety principles in IEC 61508. However, in the areas it does cover, it does not go into anything like the depth of detail, nor does it provide anything like as much assistance for the safe design of software or hardware. (On the plus side, it is much easier to read and understand than IEC 61508.) Regarding the work on the 4th Edition of IEC 60601-1-2, the decision to reference ISO 14971 instead of IEC 61508 means that the excellent work that MT15 has done on the 2nd Edition of IEC 61000-1-2 is difficult to employ directly, because it is written to align with IEC 61508. The Approach Taken by the Draft 4th Edition of IEC 60601-1-2 A great deal of work has been done towards the first published official draft of the 4th Edition of IEC 60601-1-2 by a large international team of established medical EMC experts. We won’t write here about its emissions test limits, immunity test levels, or the test methods themselves, because they could all change by the time of the first CD. Instead, we’ll discuss the approach being taken. There are many standards covering EMC performance, concerned with preventing interference to radiocommunications, telecommunications and other equipment (i.e., EM emissions), and also with ensuring that a product is reliable enough in its intended operating environment (EM immunity). These standards are used by the FCC (in the U.S.) and the EMC Directive (in Europe) [12] [13] for regulatory compliance of electrical products, but these EMC standards and associated regulatory regimes do not cover safety issues (which comes as a surprise to many manufacturers). In the case of the 2nd and 3rd editions of IEC 60601-1-2 [5], the requirements were a mixture of EMC performance and safety requirements, as the earlier quote from [4] shows. IEC 60601-1-2 has been used by regulatory authorities around the world for EMC performance compliance, as well as for medical safety, so MT23 wanted to clarify this in their 4th Edition. IEC Guide 104 subclause 5.3.3 allows safety and EMC performance aspects to be covered in the same publication, if they are clearly distinguished from each other. MT23’s initial idea was to have two sets of requirements in separate standards, but this would have proved unwieldy in practice. For example, it would have required one set of EMC tests 2 Conformity September 2008 for performance, and one for safety, whereas medical manufacturers were used to performing just one set of tests, and would have complained about the duplication of what were, essentially, the same tests but with different test levels and different performance criteria. So MT23 submitted a proposal to its parent committee SC62A. The idea was that the test methods would be common to both EMC performance and safety, but the labelling requirements, compliance criteria and test levels would be different. The safety requirements of a combined EMC performance and safety standard would either be referenced by Clause 17 of the 3rd Edition of IEC 60601-1, or by the 4th Edition of IEC 60601-1-2. Permission to proceed along those lines was officially given by SC 62A’s parent committee, TC 62, at their meeting in Auckland, New Zealand, in April 2008. The Structure of the Draft Combined EMC Performance and Safety Standard Currently, the planned structure includes two separate immunity subclauses, one for “EMC safety” and one for “EMC performance,” and a number of annexes providing guidance and rationales, including how to apply risk management techniques to EMC for safety purposes. One idea is that the resulting IEC 60601-1-2 would be very short, maybe only a few pages, referencing (or excluding) certain subclauses in the new standard. The immunity testing requirements in the work so far have had to take into account the fact that medical products are now widely used outside of the controlled environments of healthcare premises such as hospitals. Portable and implanted medical devices are now routinely expected to function safely enough in all environments (where they are not specifically excluded), and MT23 has so far considered immunity test criteria covering the EM environments associated with the following locations: • Hospital • Intensive care • Large clinic • Patient room • Surgery room • HF-Surgery • MRI • Small Clinic • Diathermy • Doctors office • Dentist • Home • Library • Shopping • (Motor-)Bike • Airplane • Railway station • Train • Ambulance • Car • Helicopter • Ship • Spacecraft • Submarine • RFID • Security • Military • Broadcast radio and TV transmitters

Table of Contents Feed for the Digital Edition of Conformity Magazine - September 2008

Conformity Magazine - September 2008 Contents Editor’s Note Commission Adopts Regulations for Internet-Based TRS Services Another Company Fined for Non-Compliance with HAC Requirements FCC Extends “Do-Not-Call” Registry Compliance Requirements Marketing Company Gets $1.4 Million Fine for Junk Faxes EU Commission Codifies Directive on TTE Market Competition EU Commission Releases Updated Standards List for the R&TTE Directive Updated Standards List for the “New” Low Voltage Directive Released New Standards List Released for the EU’s Machinery Directive The ESD Association: Voluntary Standards in Action ESD Open Forum Medical EMC Standards: Towards the 4th Edition of IEC 60601-1-2 iNARTE Informer Pre-Pulse Voltage in the HBM ESD Model Digital Interfaces and EMC Performance ESD Design Buyer’s Guide Product News Commission Publishes Updated Standards List for the EU’s Personal Protective Equipment Directive FDA Links “Human Factors” to Adverse Events with Medical Devices CPSC Actions in the News IEC Standards Update UL Standards Update Product Reviews Telcordia Standards Update From Our “You Can’t Make This Stuff Up” Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - September 2008

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