MRI's and Article 517.13

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DaveDesjardins

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Is it an oversight that section 517.13 requires branch circuits serving patient care areas be "provided with a ground path for fault current by installation in a metal raceway system,..." without addressing installation of these systems in MRI (which require the use of non-ferrous materials)? This has come up on several MRI projects in our office in which the contractor had intended to use PVC as the non-ferrous material but the code doesn't allow it. Would they need to use aluminum conduit in these cases? Maybe I'm missing something here. Any direction/comment would be appreciated.
 
Re: MRI's and Article 517.13

Let me take a try at this and then you tell me what you think, okay?

You have made reference to 517.13 Grounding of Receptacles and Fixed Electric Equipment in Patient Care Areas.

First let?s look at what a Patient Care Area is:

Patient Care Area is any portion of a health care facility wherein patients are intended to be examined or treated. ??.. The governing body of the facility designates these areas in accordance with the type of patient care anticipated and with the following definitions of the area classification.

General Care Areas is patient bedrooms, examining rooms, treatment rooms, clinics, and similar areas in which it is intended that the patient will come in contact with ordinary appliances such as a nurse call system, electrical beds, examining lamps, telephone, and entertainment devices. ?? In such areas, it may also be intended that patients be connected to electromedical devices

Critical Care Areas are those special care units, intensive care units?? patients are intended to be subjected to invasive procedures

Wet Locations are those patient care areas that are normally subject to wet conditions while patients are present.

As outlined by the definitions I can?t see where a MRI or X-ray would fall under the Patient Care Area. Also look at the part of the definition that states;
The governing body of the facility designates these areas in accordance with the type of patient care anticipated and with the following definitions of the area classification.

How did I do with this explanation?
:)
 
Re: MRI's and Article 517.13

I would think that whatever structure containing the part of an MRI machine that takes images of humans would be an examination room.
 
Re: MRI's and Article 517.13

Thanks for taking the time to respond.
So are you saying that because the definitions of General Care/Critical Care/Wet Location do not appear to include the procedures which occur in MRI (Radiology) rooms that they do not classify as Patient Care Rooms. I was stuck on Patient Care Rooms being "wherein patients are intended to be EXAMINED or treated". I guess what you are sayin makes sense. Am I understanding you correctly. Thankyou again for your input.
 
Re: MRI's and Article 517.13

Sam
Okay let?s call the MRI an examination. Now tell me what part of the MRI that is ordinary.

General Care Areas is patient bedrooms, examining rooms, treatment rooms, clinics, and similar areas in which it is intended that the patient will come in contact with ordinary appliances

I don?t think that the MRI is an ordinary piece of equipment but would fall under special appliance. What would be the outcome should EMT or Rigid conduit be around the MRI while in use?
Remember that MRI means Magnetic Resonance Imaging

Dave
I would say that a MRI or X-ray would be different than the ordinary examination room due to the phrase ordinary appliances as outlined in the definition.

Edited to add

Dave
Your referral here;
Would they need to use aluminum conduit in these cases? Maybe I'm missing something here. Any direction/comment would be appreciated.

I am not sure as to the methods and was asking the question myself.
:)

[ May 31, 2005, 05:24 PM: Message edited by: jwelectric ]
 
Re: MRI's and Article 517.13

JW your interpretations never cease to amaze me. :eek:

Patient Care Area. Any portion of a health care facility wherein patients are intended to be examined or treated. Areas of a health care facility in which patient care is administered are classified as general care areas or critical care areas, either of which may be classified as a wet location. The governing body of the facility designates these areas in accordance with the type of patient care anticipated and with the following definitions of the area classification.
Click to expand...
Your position is a MRI room is not a portion of a health care facility wherein patients are intended to be examined?

I can not accept that and I do not see how one could even think that. :confused:

Bob
 
Re: MRI's and Article 517.13

Bob
Then help us. How would you install the MRI machine?

Note my last post, I was asking.
:confused:

edited to add
where is the rest of the definition?

[ May 31, 2005, 05:37 PM: Message edited by: jwelectric ]
 
Re: MRI's and Article 517.13

DaveDesjardins, I strongly suggest you do not base your decisions on the response of just a few of us.

Wait for some more replies, we have members here that spend all their time wiring hospitals. :)
 
Re: MRI's and Article 517.13

Originally posted by jwelectric:
Bob
Then help us. How would you install the MRI machine?
Click to expand...
I do not know how to install a MRI, I have never done so. :)

That aside I see the definition differently than you do.
 
Re: MRI's and Article 517.13

517.78 (C) Noncurrent-carrying metal parts of X-ray and associated equipment (controls, tables, X-ray tube supports, transformer tanks, shielded cables, X-ray tube heads, etc.) shall be grounded in the manner specified in Article 250, as modified by 517.13(A) and 517.13(B).

I base my statement that the MRI will not be classified as a patient care area is due to the fact that X-ray equipment fall under a different section and only refers back to the patient care area as to grounding.

In the definition of patient care area we are told that there are two types, general and critical.
Under the critical we find operating rooms and the like but we do not find MRI or X-ray in either one of them.

Again I say that a MRI or a X-ray does not fall with-in the scope of patient care area but under a different section of 517.

Am I right?
:)
 
Re: MRI's and Article 517.13

JW it is my opinion, and I certainly could be wrong that you are over thinking this by a long shot.

Do they examine patients in the MRI room?

Yes or no?

In my opinion it is that simple.
 
Re: MRI's and Article 517.13

No not in the normal sense of examination.
Look at the definition of patient care as defined in the subsections, general and critical care.

Again I am not sure of my answer as I have never addressed it in this manner. About the only way I have ever addressed 517 is to cover the articles in the instructor manual.

You are probably right; I have lost the only loose screw I had left. Just looking at from every angle and am still reading and sending e-mails like crazy.

Sure hope we get more input on this tonight.

I am still asking and not claming to know, because the original post, I think, is a darn good question.
:confused:
 
Re: MRI's and Article 517.13

There are times that I wonder if we take the code as written and leave our brains at the door....
Regardless of what 517.13 says about being an exam room (which it certainly is)to install steel conduits in the walls will screw up a million dollar MRI investment. Can't do that.
Code says metal so, it has to be metal i.e aluminum, brass or some other metal for the patient care area- 6 feet around where the patient is examed; don't forget the critical branch receptacles here either- two outlets per branch, not PVC.
However, that is only for the patient care receptacles in the MR room, not all of the wiring that will be in the room. Your lighting will be DC ( pay attention to the switches that are speced, they will eat you up if you miss them.) non-ferrous and that can go in RNC along with any other outlets installed within the magnetic gradient field. The supplier of the MR will keep you out of trouble so, listen to them when they tell you what is the boundary of the magnetic field. Outside of the boundary, it's just another health care facility.
But still run what you plan on doing by the AHJ, manufacture for their blessing.

Good luck on your first MR, a lot of conventional ways of doing things just don't work around these things-
 
Re: MRI's and Article 517.13

I think an MRI room is a general care area.

517.78(c) does not apply to receptacles in a MRI room, so I'm not sure why you mentioned it :confused:

Honestly, I've never had the electricians ask about the type of conduit to use in a MRI. I assume they use alumnium conduit. According to the code book, some EMT is alumnium. For normal power, I assume one could find some AC or MC or FMC that is alumnium (but hospital grade of course).

Also, I guess the boxes have to be alumnium also!!

Some limited amounts of ferrous material can be placed in the magnet room if it is properly secured. You'll have to consult your vendor to see if that might include conduit or boxes. (I'm betting that the receptacle itself has a small amount of steel in it).

Steve
 
Re: MRI's and Article 517.13

In some MRI installations we do use EMT and standard stamped steel boxes inside walls and where it can be secured to the structure above the ceiling. The fixtures and whips are aluminum as well as anything that can not be secured to the structural framing or concrete.

All wiring must go through RF filters where a single point grounding bar or stud is furnished.

The metallic wiring methods inside the room to the filters will be isolated with a nonmetallic dielectric buffer from the wiring and metal outside the shielding envelope, so regardless of what type of conduit is used a redundant ground path utilizing the conduit can not be achieved.

Rick, Phillips is recommending AC lighting with 50/100% switching in their rooms now, but GE, Siemens, and Hitachi (I'm not positive about Hitachi) are still asking for 120V DC with dimming

Roger
 
Re: MRI's and Article 517.13

I figure in time the engineers will devise a way to keep the magnetic field confined closer to the patient. I was not aware of the A/C lighting being an option. I just remember the old light bulbs from my hippie days with a magnet under the element that caused the element to wave back and forth. It may not be long before conventional wiring CAN be used around these things. Sounds like Phillips is getting a handle already.
From what I can gather from our MR physicist it isn't so much the iron content nearby but how much the iron is able to move that gives them the blues. Once the deflected field is known and the gradients accounted for, they can compensate for small amounts.
I would still leave my credit cards outside the room.....;-)
 
Re: MRI's and Article 517.13

Thanks again for all of the input. It seems that my original question about whether or not it was an oversight by the NEC was not answered however. I found myself in the same arguement with people in my office regarding the MRI (or any Radiology room for that matter) being an Exam room. I still am not sure of the answer. Again any additional information/experience is appretiated.
 
Re: MRI's and Article 517.13

I noticed that too. I'm gonna go out on a limb and agree that it might be an oversight. I don't work in health care buildings or know much about the codes for it though.

Edit: Or maybe they just don't care because you can get aluminum.

[ June 02, 2005, 02:22 PM: Message edited by: physis ]
 
Re: MRI's and Article 517.13

It is not an oversite. Due to the shielding and isolation that accompanies it, it is simply an issue that can not be achieved. In reality a patient will not have any contact with an electrical apparatus while in the magnet.

Even if a "Code Blue" situation occurs, the patient will need to be removed from the room before any life saving procedure that involves metal utensils takes place, or, the magnet must be taken offline.

Receptacles in the room are only for house keeping and possibly a TV in some rooms. In most rooms the cost of installing a TV with the filters and special TV itself is a multi thousand dollar proposition and is not done.

Another issue to consider is that the magnet table is usually more than 6' from the walls which puts the receptacles outside the patient vicinity.

Roger

[ June 02, 2005, 05:44 PM: Message edited by: roger ]
 
Re: MRI's and Article 517.13

We wired an MRI machine during the summer of 2004. The entire interior of the room was shielded from outside interference with sheet steel. We were told that we could use EMT, steel Wiremold(R), aluminum conduit, or any other metallic wiring method for the 120 volt 20 amp branch circuits provided that it did not stick out of the ceiling or the wall too far.

One thing that we did have to do was to do all metal cutting and filing outside of the room so that we only had to vacuum up coarser drilling chips.

The larger wireway for the wiring to the MRI had to be aluminum or stainless steel but that was because it was in close proximity to the MRI machine.

By the way, aluminum is slightly magnetic with a permeability 3.2 times that of a vacuum. Compare that to transformer steel which has a permeability of around 4,000 to 5,000. If you have ever tried to find a steel part in aluminum machine tool chips using a magnet, you figure that out very quickly.
 
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