EBME Forums Forums Maintenance Technical Assistance Class III equipment

Sorry about the delay in replying, been busy preparing for a trip to Uganda on Tuesday.

As always, lots of interesting discussion regarding safety testing. My initial question was does anyone know of any symbols that would be used on Class III medical equipment.

Given the situation in Ugandan hospitals, a new biomed is (very) likely to work in a hospital / department where nothing has been safety tested (since arrival in the country) and there's no record of what is and isn't working, so everything will need to be tested.

However, I have come across equipment which does appear to fall into the definition of Class III (often fake equipment from a certain Asian country), so it would be good if we could teach the students how to spot these and what tests to carry out on them.

As a slight side, we generally teach that it's a good idea to perform electrical safety tests every year as part of the PPM. Although there are more detailed guidelines about how often to perform a test in the service manual, these are often unavailable, so a one-size-fits-all system is probably best for now. Though we do teach them to check the manual where possible for more details.

To answer the question about marking, I do not think there is a specific one.
I doubt if you will find anything powered purly by SELV, as has been stated previously if it has a seperate charger/power supply then the whole system must be tested as a mains powered unit to class I or II as appropriate.
If it is purely battery powered with no direct or indirect mains connection then that is obvious.
The B, BF, CF markings are the same what ever class the equipment is.
Robert

@Steven: maybe you need to look at this stuff a little differently, and (instead of looking for, and relying upon, equipment markings) teach your students to be able to work out "Class" for themselves.

We could also ask (especially in the context of the situation you describe):- does "Class" matter overly much anyway? When it comes to testing, and working on the kit, what practical difference does it make?

The time may well be better spent getting the guys au fait with the electrical safety tester of choice (if any). Or better still (and the way I would approach things), getting them able to understand and carry out valid electrical safety tests without an automatic EST - but rather using Common or Garden test equipment (Meggars, multimeters, and what-have-you) - plus (as has been mentioned a few times earlier in the thread) the importance of visual inspection (not to mention opening up the mains plug, checking for a decent earth, and the correct value of fuse).

Then get them used to carrying out EST on "everything* in the room" (ward, clinic, theatre, wherever) regardless of what Class it may be, or indeed "who else" might be "responsible" for it (no-one, if my own experiences are anything to go by). I would suggest that you need to instill in them the "Biomed Ethos", and the idea of the Biomed being the Custodian of Electrical Safety in the hospital. In other words (and as some may remember me saying many times in the past):- someone has to give a [censored]!

By the way, I am very familiar with the type of scenario you're faced with out there, and it's one of the reasons that I always advocate what we might call a "generic" approach to biomed work. Or if you like, a consistent approach to PM etc. regardless of manufacture (or indeed, what the manufacturer says - if anything; which may not really be applicable "out there" anyway). Let's be honest, the need is to get properly conducted PM etc. up and running in the first place. The "niceties" (the minutiae of electrical safety, and comparing risks to patients from this or that equipment, and all the rest) can always be developed later (if at all).

* Everything with a mains plug, that is.

@Sean 06:52: yes, I agree with you there.

@Sean 07:06: thanks for looking. I'll bet it has (the all-important) C.E. mark, though.

I agree with RoJo: When it is mains powered it is not class III, when it is powered from a safety charger, it is class III, but the charger is not class III. Just note about the symbol in wikipedia (http://en.wikipedia.org/wiki/Appliance_classes#Class_III) - it is correct.

Yes ... but note what the Wiki page says about medical devices.

In short, that marking (Class III) should never appear in a clinical environment.

And what, exactly, is a "safety charger"?

If it's got a mains plug on it, then it gets tested. Why complicate matters beyond that?