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

What checks do you do on your electric beds: -

1. Routine PAT testing
or
2. Routine Medical Safety Testing

With the increase in electrical beds on wards these days and the fact that they are most often classified as Class II Type B to BSEN60601, the only correct way to electrically test these items is option 2 above.
Traditionally beds have been maintained by Estates Fitters and with the new electrical beds being PAT tested annually by Estates Electricians. As far as I am aware, there is no PAT tester that will test the applied part e.g. Type B, the metal frame on the bed?

What do you all do on this, are there any EBME departments out there that carry out medical safety testing on electric beds etc...? What do your Estates department do?

I recently spoke to a Huntleigh Technician who modified one of our beds, he said that all they do is a PAT test and not a medical safety check, although the equipment is classified as above!
We medically safety tested the bed after the modification to be sure.
Some beds have aux power sockets to power air mattress devices such as the Nimbus 3 etc, which raises another question about testing these devices as one complete system.

Mark

Okay, no responses!

Put it this way: -

Does anybody use a PAT Tester to electrically check a medical device?

The types of medical device's that I am referring to are the type that maybe are more traditionally maintained by Estates staff, e.g. electric beds, air mattress pumps etc...

Has this issue never been raised before?

Mark

Mark, I am not familiar at all with patient beds but just to point out what I think is a mistake made by a number of individuals, not just yourself, type B does not refer to applied parts. The classification "F" determines the applied part (floating part) and the prefix (B or C in this case) determines the degree of isolation from mains parts to applied parts e.g. "BF" or "CF" or alternatively from mains parts to the equipment enclosure if there are no applied parts i.e. "B" I think.

So, on the face of it, the frame of the beds you give as examples would not be tested as applied parts if the classification is Class "1B" or Class "2B" in my opinion because there are no intentional applied parts to test. "B" is the equipment classification for medical equipment with no intended patient applied parts, either type Class1 (protectively earthed) or type Class2 (no protective earth) is used to specify the basic level of mains protection afforded by mains powered equipment.

RL,

It clearly states in BS EN 60601-1:1990 section 2.1.5 that an applied part is defined as: -

2.1.5
*APPLIED PART
a part of the EQUIPMENT which in NORMAL USE:
— necessarily comes into physical contact with the PATIENT for the EQUIPMENT to perform its function;
or
— can be brought into contact with the PATIENT; or
— needs to be touched by the PATIENT.

Also section 2.1.24 states Type B is an applied part: -

2.1.24
*TYPE B APPLIED PART
APPLIED PARTS complying with the specified requirements of this Standard to provide protection against
electric shock, particularly regarding allowable LEAKAGE CURRENT and marked with symbol 1, Table D.II,
of Appendix D
NOTE TYPE APPLIED PARTS are not suitable for DIRECT CARDIAC APPLICATION.

Mark

Thanks for that Mark, my apologies for poor terminology and poor explanation of what I'm getting at. B applied parts, as defined in the standard do exist - by the definition of the standards the "B applied part" (of the bed) you refer to does not exist in practice because the bed frame can be classifed as enclosure can't it? (section 2.1.6). Is it, in fact, applied part or enclosure? Does the manufacturer need to specify this? Type B aplied parts protection applies in any case.

If there were applied parts then B, BF or CF would apply to them but in practice it it more likely that manufacturers would define the equipment as BF or CF if there were conductive patient connections. Defining the bed as applied part rather than enclosure is stretching it a bit I think.

Looking at the standard - applied parts refer to those parts that constitute the patient connection (section 2.1.23) don't they? Surely you can only call the bed frame an applied part if it is part of an electrical circuit (patient circuit; section 2.1.15) that contains a patient connection?

RL- I disgree. An applied part is essentially any part of the equipment with which the patient could make contact in normal use. The bed frame should therefore be considered an an Applied Part, and one with which we can expect the patient is likely to make good contact. Whether or not you intentionally applied the part would be academic to the patient who received a shock from it.
(ps: The Equipment is Class 1 or 2; its Applied Parts are Type B, BF or CF - as per the Standard Mark quotes).

I agree with Mark, beds should be tested as medical devices (as should any electrical device used in the 'patient area')- but commonly aren't because traditionally they were often the remit of Estates Depts.
Bed management at this hospital has now been contracted out, but this level of safety testing was specified in the agreeemnt.

RL,
If the patient can come into contact with the enclosure then it must become an applied part, as this would be the overriding factor within the standard?
Mark

Yes but all I'm saying is that the definition of enclosure could also apply to the bed frame. I suppose it doesn't really matter because the mains protection afforded by a "B applied part" applies in either case. I do actually think a medical safety test is essential for mains B, BF or CF equipment.

We are talking about definitions when in practice the tests that will be applied are the same aren't they? Irrespective of what we call the applied part or enclosure? Is this the case?

An understanding of which is Enclosure (Class 1 or 2) and what is Appled Part (Type B, BF, or CF) will inform how you conduct your test. A 1-BF device for example - conductive parts on the Enclosure are likely to be protectively-earthed but those on the Applied Part not.

To go back to the bed example, to quote from Appendix A of the 60601-1 Standard; "A table top supporting a patient is an Applied Part ...... conductive parts of the table top would therefore be classified as Patient Connections"

Ged,

Thanks for the info, Mark