IEC 60601-1 3rd edition Clause 9.2.2 Trapping Zone (Acceptable Gaps)

[leroybrown]

Hi all,

This is the first time my company is designing an examination chair to the 3rd edition. As such there are many more safety criteria and tests with which we have to comply. My question revolves around clause 9.2.2.2 for acceptable gaps. Can someone please explain to me how a footrest on an electrical moving chair can meet the acceptable gap requirement for a foot and still meet human factor considerations? Our 3rd party inspector says that the footrest must be >100 mm from the ground to comply. Really? What purpose will the footrest serve then? Or is that the point?

I look forward to any insight!!

 

[Mark Meer]

It sounds like, as you say, the inspector's expectations are contrary to the intended use of the footrest. As such, I would site 9.2.2.1 which states:

"If implementation of the above protective measures would be inconsistent with the INTENDED USE..., control of the relevant motion shall comply with 9.2.2.6."
(9.2.2.6. being specific controls for speed of movement).

Regardless of what you argue, it'll likely stem from your Risk Management file. If you haven't done so already, add a risk-evaluation line-item in your risk file to demonstrate that you've considered trapping hazards...

 

[leroybrown]

Thanks for the help! I have another question now. I'm only familiar with the third edition requirements. Are the second edition requirements regarding trapping zones comparable? I'm trying to establish a baseline for comparing the trapping zone requirements between editions as additional trapping zones, according to our third party inspector, have been identified on our new chair.

 

[PaulGr]

Second edition did not contain a list of acceptable gaps to determine if a trapping zone would lead to a hazard so your approach would probably be difficult.

 

[Peter Selvey]

Clause 9.2.2.1 has a quad option "or" statement, i.e. four possible solutions, with the supplementary 5th solution if those are not practical (as Mark Meer already mentioned). Study each option carefully before turning to risk management.

You could be tricked (and the inspector also) into thinking that a trapping zone is not allowed, this is not true, keeping the distances outside the limits in Table 20 is just one of the 5 options.

If you do turn to risk management, take care to check the situation carefully and also offer an alternate solution (i.e. revised criteria, don't just say it is "not applicable").

 

[leroybrown]

Via a very thorough risk evaluation, additional info provided to the operator and some design modification, our exam chair passed the requirement.

I will now work on beefing up our risk management process to incorporate more of the 60601-1 requirements. This will definitely minimize the stress level for our next product submission in relation to testing.