15.3.3 Ball Impact Test requirements in IEC 60601-1

[monty007]

Hi all. I have a question about the ball impact test requirements in IEC 60601-1. For body worn devices the ball impact test applies. How about if the device is tiny, like a hearing aid or something similar? Surely such a tiny device cannot withstand a 0.5kg ball impact from 1.3m? Does this apply to all body work devices or do you think this is usually excluded from such devices?
Any advice would be appreciated.
Thanks in advance.

 

[Pads38]

Hi Monty,

The impact test sets out to show "...sufficient resistance to impact to protect against unacceptable risk." Note it doesn't say "must not break".

If you have a look at the assessment criteria set out in 15.3.1 they are all concerned about the risks of damage to the enclosure allowing access to electrically live parts. But with a hearing aid you won't have any hazardous voltages, so you have no risk of electrical shock whatever happens.

Now, if you check the rationale to 15.3.3, in Annex A, there is an example given of the use of risk management where the manufacturer decides that the subclause does not mitigate an unacceptable risk. (The example given is for installed equipment - but the concept is the same).

I would suggest that you could justify that the impact test is not relevant. But instead you could look to the drop test of 15.3.4 to provide a more relevant test. For hand held it suggests a drop height of 1m or more. Now, if you were to perform some drop tests from 'ear height' (say a near worst case of 1.8m) I think that might be more relevant.

There is a 'Particular' standard for hearing aids - 60601-2-66. I believe that this modifies some of the test requirements, to be more relevant.

From an IEC web page about -2-66

Many subclauses of the general Standard are not applicable to hearing aids – for instance they do not present electrical, fire or heat hazards owing to their low voltage and low energy characteristics.

However, protection against mechanical hazards is given special attention in the particular Standard and devices are submitted to drop tests. The Standard states that hearing instruments "shall have mechanical strength and shall not result in an unacceptable risk due to moulding stress or when subjected to mechanical stress caused by pushing, impact, dropping, and rough handling".

As a hearing instrument is frequently installed entirely or partially in ear canals "rough surfaces, sharp corners and edges that could result in an unacceptable risk shall be avoided or covered".

https://iecetech.org/issue/2013-05/Ensuring-safer-design-for-hearing-aids

 

[monty007]

Thank you for your reply. The hearing aid was the only example of a small wearable that I could think of. The device im working on isn't a hearing aid but is a small usb chargeable device which if impacted by the .5kg ball end up with a cracked enclosure. The crack in the enclosure isn't itself a problem but because its also has an IP22 requirement this may cause a problem.
There isn't anything that gives guidance on the size of device that this applies to so I guess its a risk management thing as you have suggested.
Thanks again you your reply.

 

[Anjali Nair]

Hi monty,

I am facing a similar issue with the ball test could you please reach out to me at [email protected] to have a discussion on this?

 

[VinceTech]

I would argue that ball impact test is not necessary to a small body worn device like a hearing aid device.
You may assessment in what chance the device may subject to such a impact. and it is feasible the impact face is that much when it is worn on body.