FEATURE TEST & MEASUREMENT
Setting the new standard for hazard-based testing
define hazard-based requirements, using engineering principles and taking into account relevant IEC equipment standards and pilot documents. To a large extent this makes IEC 62368-1 a technology independent safety standard allowing for more design freedom. IEC 60065 and IEC 60950-1 follow a set
of rules and criteria outlined in both standards. IEC 62368-1 requires the identification of safety hazards in the early product development phase so that subsequent product design eliminates them. It also provides more performance options to demonstrate compliance. The following is a typical example of the Hazard Based Approach: • Identify the energy sources by reviewing the product and its associated schematics
• Take measurements to determine the energy levels (Class 1, 2, or 3) and identify if the sources are hazardous
• If they are hazardous identify the means by which energy can be transferred to a body part, design the safeguards that will stop this and measure their effectiveness.
Jean-Louis Evans, Managing Director at TÜV SÜD Product Service and at its sister company, TÜV SÜD BABT, considers the implications of the new hazard based standards approach for electronics testing
D
ue to technology convergence, the same multi-media products are
increasingly falling under two safety standards - IEC 60065 (audio, video and similar electronic apparatus) and IEC 60950-1 (information technology equipment). IEC Technical Committee (TC) 108 has therefore created a new ‘hazard- based’ standard, which would cover both. Consequently, IEC 62368-1 (Audio/video,
information and communication technology equipment - Part 1: Safety requirements) was published in January 2010. Although the new standard covers products that fall under IEC 60065 and IEC 60950-1, this is not a simple merger of them, but is entirely new and has no similarity in its structure to the two standards that it is intended to replace. This is the first time that a hazard- based approach has been taken to product safety and it is important to recognise at this point that risk assessment and risk management does not form part of the new standard, rather it still contains specific requirements and compliance criteria the same as its predecessors, but follows a different methodology. The basic process being to identify and classify energy sources in the product, identify safeguards required
20 DECEMBER/JANUARY 2015 | ELECTRONICS
for protection and then qualify the effectiveness of those safeguards. This is quite different from IEC 60601 3rd Ed, the medical electrical safety standard which does include risk management as part of its requirements, and it is important not to confuse the two as Hazard Based Safety Engineering is not the same.
SETTING THE NEW STANDARD As the new IEC 62368-1 represents a significant departure from traditional standards, it has initially been introduced as a voluntary alternative to the existing standards, but is expected to be fully adopted in the next few years. It may now be followed by electronics manufacturers in their safety testing process instead of the two older standards, with early adoption giving them the opportunity to take advantage of the increased flexibility offered by the new standard.
The hazard-based approach HBSE (Hazard-based Safety Engineering) was used as a principal methodology in developing IEC 62368-1, which defines a hazard as an energy source that exceeds the body susceptibility limits. The philosophy applied has been to
Figure 1:
The new hazard based approach to electronics device testing is intended to offer increased product safety
CLASSES OF ENERGY SOURCE A class 1 energy source, under contact with a body part, may be detectable, but is not likely to cause injury. A Class 2 source is an energy source with levels exceeding Class 1 limits and not exceeding Class 2 limits under normal operating conditions, abnormal operating conditions, or single fault conditions. Under contact with a body part, a Class 2 energy source may be painful, but is not likely to cause an injury. However, the energy in a Class 3 source, under contact with a body part, is capable of causing injury. For fire, the energy in a Class 3 source may cause ignition and the spread of flames where fuel is available. IEC TC 108 considers that the new
standard is no different to the legacy standards IEC 60065 and IEC 60950-1, as it is a complete product safety standard with specific requirements and compliance criteria. However, IEC 62368-1 introduces a completely new methodology, turning on its head the well-established and understood principles of IEC 60065 and IEC 60950 and requires a new mind-set when applying the standard. The new standard should provide greater
flexibility in proving safe design, it should be technology independent and should better allow for technology advancement. But are you prepared for what is in effect a fundamental change in how to demonstrate product safety compliance?
TÜV SÜD Product Service
www.tuv-sud.co.uk 01489 558 100
Enter 207 / ELECTRONICS
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