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A new safety standard

IEC 62368-1 is the new hazard-based product safety standard coming into effect this December. What does this mean for design engineers? Neil Tyler reports

IEC 62368-1 comes into force worldwide from 20th December and it brings with it a totally new set of engineering principles and terminologies. Significantly, it’s the first time that a hazard-based testing approach has been taken with these types of electronic equipment and comes in response to the growing convergence in, and the development of, new ‘state of the art’ technologies.

Multi-media and communications products, for example, had been falling increasingly under both the IEC 60065 (AV equipment) and IEC 60950-1 (IT equipment) standards, creating a degree of confusion among manufacturers. In response the IEC Technical Committee (TC) 108 created the new ‘hazard-based’ standard - IEC 62368-1, which while it isn’t a merger of existing standards does cover the older standards.

“This is the first time that a hazard-based, rather than test-based, approach has been taken with product safety. To a large extent this makes IEC 62368-1 a technology independent safety standard, allowing for more design freedom,” explained Richard Poate, senior manager at TUV SUD.

“Its introduction has caused some problems in terms of the compliance methodology, as it’s the first time the hazard approach has been taken and people will need to be aware that it is not just a repackaging of the existing standards - although at first glance it’s certainly possible to spot many familiar aspects to it,” he conceded. “But the hazard based approach that’s been taken means it is not just a simple merger of the previous two standards. It is a fundamentally different approach to proving compliance and that your product is safe.”

The two older standards followed a set of prescribed rules, while IEC 62368-1 now requires the identification of safety hazards in the early product development phase.

“The standard takes a proactive risk-based approach by identifying hazards and then testing the effectiveness of the chosen safeguards,” Poate said.

It also provides more performance options to demonstrate compliance. With this new standard coming into force in a matter of weeks, what exactly are the benefits?

“While the previous standards were clear and addressed specific markets as is always the case with technology, new products and designs move very quickly while standards don’t. So, as new products appeared, there was growing confusion as to which standards should be applied.

“Take the example of a Sky Box. It has a video recording capability but open it up and it’s essentially a personal computer. “As a result, different countries wanted products tested to one standard, others to another. The whole thing,” according to Poate, “was getting ‘messy’.”

As a result IEC 62368-1 was conceived as a replacement for these existing standards.

“The European version of IEC 62368 has been around for a number of years, but becomes mandatory in December,” Pate explains.

It comes at an interesting time for the UK with Brexit set to happen but Poate suggested that whatever is agreed by the UK and Europe, in their on-going trade talks, it would take a large team to re-write standards that have been developed over many years.

“No matter what deal is agreed, I think from next year the UK will look to operate with a harmonised set of European standards. There’s really no way we can re-write the thousands of different standards that are currently in operation. “Going forward, however, I think there may be a push towards developing particular UK standards. However, I would argue that they would have to stay aligned to European standards, as manufacturers will not want to work with additional barriers to trade.”

While the biggest change with IEC 62368-1 is the adoption of a hazard rather than test-based approach, the testing requirement for batteries has also become more onerous.

“The requirements for batteries are more stringent and the standard has looked to become more ‘future proof’, with the aim of keeping up with developments in the technology. We are seeing more battery powered consumer products and a move away from mains-powered devices to lithium ion rechargeable batteries – the standard needed to reflect that.”

A change of mindset

According to Poate IEC 62368-1 will require a significant change in mindset among engineers, when it comes to testing and compliance.

“With this approach an engineer is not designing a product to meet a particular set of criteria in order pass a specific test,” he explained.

“Rather they will have to identify possible hazards in their products, quantify them and then restrict access to those hazards.

“In the past, engineers would be confronted with a prescriptive set of requirements against which their design would need to be validated – a list drawn up by those who wrote the standard. It was very easy to follow, but how did you as an engineer know that all the hazards had been addressed? You were only working with those already identified, not new ones.

“IEC 62368-1 has turned that approach on its head and forced the design engineer to look at their product afresh, and requires them to identify potential hazards. That sounds easy, but can be quite challenging, especially for engineers who are used to working with a set of prescriptive tests,” suggested Poate.

Accordingly, while the new standard doesn’t throw away those types of tests, it does call for the identification of likely hazards to take place first and only then for the use of prescriptive tests to pass or fail that device.

“IEC 62638-1 is a hazard based safety engineering methodology which requires you to identify potential hazards, whether that concerns electrical, thermal or mechanical safety and so on, and mitigate against them.

“Take a fan that sits inside a laptop, for example. It has a moving element - rotating blades - so that would be identified as a low risk hazard – but whatever the level of hazard, the concept is the same.

“Taking this example, you will have identified the blades as a hazard, documented that and by doing so ensured that anyone would be able to see what was identified as a hazard and, perhaps, what was overlooked.”

According to Poate, once the hazards have been identified, then the various safeguards required can be selected and the necessary prescriptive testing carried out.

“You are being asked to manage the risk associated with the hazardous part by employing safeguards. Only then do you fall back on the prescriptive testing that was at the heart of the previous standards, so we can test the integrity of those safeguards that have been selected.

“This is the heart of the new standard. You are identifying the risks first, then applying the safeguards and testing them.”

The biggest benefit from this new approach is that the engineer does not have to design to a specific standard, so there’s more flexibility as a result.

“To start with it will be a bit more restrictive – we are replacing a tried and trusted methodology with something very different. Engineers will not have used this approach before but, in time, I believe that once they get use to the new methodology it will give them much more freedom with their designs,” argued Poate.

The prescriptive test-based approach of the old standards left little room for subjectivity, as they required engineers to apply specific tests to prove compliance. By contrast, IEC 62368-1 takes a more subjective approach which relies on engineering expertise to identify potential hazards.

“It’s not prescriptive and will allow designers to think outside the box, with the potential for radically new designs that could use new materials or be lighter, more cost effective, or come with better features.”

However, not every individual engineer may identify exactly the same hazards when considering a similar product.

“Only time will tell if this new, more flexible, less objective approach will ensure that products remain safe,” concluded Poate.

Author
Neil Tyler

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