Due 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.
While there will be a long transition period, this is the first time that a hazard-based approach has been taken to product safety and it is important to understand that risk assessment and risk management do not form part of the new standard. While it still contains specific requirements and compliance criteria that are the same as its predecessors, it follows an entirely different methodology, the basic process being to identify and classify energy sources in the product, identify safeguards required for protection and then qualify the effectiveness of those safeguards.
A safeguard is defined as “a device or scheme or system that is interposed between an energy source capable of causing pain or injury and a body part, and reduces the likelihood of transfer of energy capable of causing pain or injury to a body part.
The previous standards, 60950-1 and 60065, closely dictated product design, and were known as ‘prescriptive’ standards. The new philosophy applied has been to 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.
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 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.
Hazard-based Safety Engineering
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.
An energy source can be:
- Electric shock Electrically-caused fire
- Chemical (e.g., chemicals, including batteries)
- Mechanical (e.g., moving parts, sharp edges, physical stability)
- Thermal (e.g., skin burn)
- Radiation (e.g., ionizing, non-ionizing, acoustic)
While 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 and design the safeguards that will stop this and measure their effectiveness.
There is also a hierarchy of safeguards, which can be applied, that must be taken into account:
- 1. Equipment safeguards - do not require any knowledge or actions by persons coming into contact with the equipment.
- 2. Installation safeguards - when a safety characteristic can only be provided after installation. For example, the equipment has to be bolted to the floor to provide stability.
- 3. Behavioural safeguards - when the equipment requires an energy source to be accessible.
Classes of energy source
Unless otherwise specified, a Class 1 source is an energy source with levels not exceeding class 1 limits under:
- normal operating conditions; and
- abnormal operating conditions that do not lead to a single fault condition; and
- single fault conditions that do not result in class 2 limits being exceeded.
Under normal operating conditions and abnormal operating conditions, the energy in a Class 1 source, in contact with a body part, may be detectable, but is not painful nor is it likely to cause an injury. For fire, the energy in a class 1 source is not likely to cause ignition. Under single fault conditions, a Class 1 energy source, under contact with a body part, may be painful, 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. For fire, the energy in a Class 2 source can cause ignition under some conditions.
A Class 3 source is an energy source with levels exceeding Class 2 limits under normal operating conditions, abnormal operating conditions, or single fault conditions, or any energy source declared to be a Class 3 source. 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.
An advantage of early adoption by manufacturers is that they will have plenty of time to become familiar with the new standard, and adapt design approaches accordingly. 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?