EBME Forums Forums Management Medical Equipment Management Electric Beds - PAT or Medical Safety Testing

Dear Mark.

Since you know the standard so thoroughly I have to wonder why you asked for opinions in the first instance?

As for "read the standard" as a response don't be cheeky!

As I said before Part 1 very specificaly defines Enclosure, but then very broadly defines Applied Part.

If it was really clear then poor Ged would not have had to expend such a large amount of virtual web ink clarifying it for me!

What this brings to home for me is the generality of the Part 1 and therefore, the particular usefulness of the Part 2 documents from BSI.

In addition to considering whether time is well spent doing an Applied Part test in such an odd situation, there is the problem of avoiding damage to equipment from running inappropriate tests. The Applied Part tests are indeed more stringent but they are potentially destructive.

As can be seen from other areas on this site such as Reliability Centred Maintenance we don't generally have the time to do any more tests than is absolutely necessary. It is perhaps unfortunate, but working out what is really necessary is nowdays at the heart of our work.

Marc

Hello there guys, just to add a little to this subject or throw a spanner in the works.

I was previously employed by one of the main UK electric bed manufacturers (Clue: Blue Foot and head boards).

When we serviced the beds for clients we would use a Robin SmartPat5000 electrical saftey tester and using pre-programmed code 104.

Our reason was because our bed frames use 24v dc to power all actuators and controls, and only has 230v ac supplying power to the Linak cb14 control box.

So we therefore safety tested our products using class 1b. In addition all metal frame parts are linked together via then metal bushings and earth straps to the main mattress platform.

Hope this helps, as this is the same system of testing I use on all the Trsut beds I'm responsible for.

pete

What standards were the beds manufactured to Peter?

ok cant remember fully but heres the info from the service manual.

Electrial Safety standards:
Complies with 60601-1 (BS 5724: part 1, IEC 601-1)

Electrical shock protection:
Class 1 Type B

EMC:
Complies with BS EN 60601-1-2

Equipotential Terminal:
Complies with IEC 601-1

This Information applies to the Huntleigh Healthcare/Nesbit Evans Contoura 880 and Variants, and Information was from the Service manual we have in our possession.

Hope it answers your question

The way I see it is 'if your not sure ask the manufacturer'. Huntleigh beds are marked and are tested here to 1B or 2B accordingly depending on the model. The pressure relief systems are also marked eg 1BF on Nimbus 2. This is despite being totally enclosed in a plastic case with only AIR exiting the case and going to the mattress through non-conductive plastic pipes.
The manufacturer SHOULD be the authority on this. We are supposed to adhere to manufacturers instruction and reccommendation.

Can I ask why EBME departments are carring out what is essentially an estates function?

Where is the cutoff point, I agree that specialist rotational beds should be mainatained by EBME'S but standard hospital beds I would argue are out of our scope.

We in wolves maintain all electrical beds as they are classified as medical equipment to be safety tested IAW IEC 601. etc and i guess it's because we have techs in all the specialized area's (ITU,Theatres,Cardiac etc) we are the users first port of call.

I visited a bed manufacturer as part of a purchase evaluation and saw a lot of work going in to strapping all the parts of the frame to earth. When I asked why they said because of electrical safety. All the actuators and controls etc were either low voltage or fully enclosed in their own housing either class 2 or earthed. i.e. no mains was near the bed frame.
Anyone any idea as to why all parts of a bed have to be earthed. Do they have to be earthed? I can think of many medical devices with metal parts that are not physically earthed as the mains cannot come near them.
Are you actually putting the patient at greater risk by providing a good earth return for fault currents? Rather than having an isolated bed frame.
I asked the company why they did this and they said "because we have to" but could not quote any regulation.
I would be interested to know your thoughts. And I expect the manufacturer would be as well as they said it cost them a fortune in man hours adding the studs to the frame and then wiring them all up.
Regards
Robert

I suppose electrostatic discharge is an issue as well as electrical safety. Enclosure-leakage and patient leakage values obtained during safety testing might also be an issue since the standard for beds establishes a significant amount of the bed frame as applied parts.

Can't really get my head around this since what's defined as applied parts on beds are likely to be earthed and this might cause conflicts with the results that are obtained using safety tests. e.g. patient leakage tests with mains on applied parts and with patient leakage to applied parts with earth O/C. In these circumstances one could reasonably expect the limits to be exceeded I think (especially for beds classified as CF but even BF I think). The points I was trying to get across in earlier postings.

A technique or rationale for test methods would be useful if provided in the standards. The manufacturers probably just comply with the advice of the notifed body or whatever their regulatory people say.