steveve1
Member
- Location
- Tucson, AZ
Looking for a little help finding suitable boxes for concealed work inside of the RF shielding. Can't seem to find any stainless steel products. Has anyone out there done one of these rooms recently?
MRI Exam Room Wiring
- Thread starter steveve1
- Start date
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wirenut3
Member
- Location
- Northern New Jersey
One we did a few years ago was all done in pvc- no metal whatsoever.
Better check that.
Better check that.
One was on an outside wall and they had to block off 6 parking spots. The old ones would rip stuff out of peoples pockets, don't know if the new ones will.
Large masses of metal affect the calibration of the machine. A big truck parked outside today and not tomorrow would affect the way the thing worked, ( that information is from the vendor rep.)
Better check that.
Mitsubishi an GE wanted no magnetic material in the same room. You couldn't secure metal boxs and emt to studs. The studs were wood and the screws bronze or brass.
One was on an outside wall and they had to block off 6 parking spots. The old ones would rip stuff out of peoples pockets, don't know if the new ones will.
Large masses of metal affect the calibration of the machine. A big truck parked outside today and not tomorrow would affect the way the thing worked, ( that information is from the vendor rep.)
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
kwired
Electron manager
- Location
- NE Nebraska
I don't know a lot about MRI but have understood that magnetic materials are not desired which is fairly obvious. I also believe non magnetic materials effect calibration. I understand they have to calibrate the equipment to the room. If anything in the room changes they must recalibrate.
I have done many MRI's GE, Phillips, Mitsubishi (open) and Seimens and have done all in EMT and steel boxes.
Most are inside an alluminum evelope but I will try to post some pictures of a Phillips installation inside of a copper envelope tomorrow.
Roger
Most are inside an alluminum evelope but I will try to post some pictures of a Phillips installation inside of a copper envelope tomorrow.
Roger
Must be a different set of specs then we get from GE and Mitsubishi.
Must of been poor shielding, what do you think would happen to the mobile units they set up in parking lots?
Yes they will and any magnetic metallic particles in your body as well.
Maybe from vibration but if proper shielding is in place what's outside the room should not effect the magnet.
Roger
steveve1
Member
- Location
- Tucson, AZ
The manuf. is Seimens. This is new construction in an existing hospital. The engineer has specified aluminum rigid conduit and nonmagnetic boxes in the exam room. There are a total of 8 back boxes required for recepts, lighting, and controls; each would require an 1-5/8" ring to flush with interior acoustical paneling. The rf shielding is 3 oz. copper paneling by ETS-Lindgren. Im looking for a listed stainless steel back box and extention ring but haven't had any luck. I could maybe get a local stainless fab company to make them but what of the listing requirements?
Any thoughts or help is appreciated...Thanks
Any thoughts or help is appreciated...Thanks
- Location
- Massachusetts
If it was me I would send an RFI requesting the engineer to specify the boxes he wants used. In other words make it their problem.
masterinbama
Senior Member
- Location
- Huntsville Alabama
So do I.
Steve, you also state the engineer wants this, that is not necessarily what the manufacturer requires.
Roger
renosteinke
Senior Member
- Location
- NE Arkansas
A few things need to be stressed:
Some units have supercooled magnets that are capable of pulling fillings out of teeth and pins from bones. "Slightly magnetic" is not good enough.
Many, if not most, forms of stainless steel are at least 'slightly' magnetic. That's enough to cause an issue.
Apart from boxes, most wire nuts are magnetic.
Don't forget that the magnetic field will also fry your credit cards, erase your I-Pod (goodbye, Billy Idol!), and probably drive your cell phone insane.
I agree that the burden is on the designer to tell you what you need to do. In place of the usual electrical boxes, you might have to use PVC, "Bell" boxes (zinc or aluminum), or larger 'pull cans' made of stainless. Whatever you get, double-check the assorted screws, etc., for magnetic properties.
Some units have supercooled magnets that are capable of pulling fillings out of teeth and pins from bones. "Slightly magnetic" is not good enough.
Many, if not most, forms of stainless steel are at least 'slightly' magnetic. That's enough to cause an issue.
Apart from boxes, most wire nuts are magnetic.
Don't forget that the magnetic field will also fry your credit cards, erase your I-Pod (goodbye, Billy Idol!), and probably drive your cell phone insane.
I agree that the burden is on the designer to tell you what you need to do. In place of the usual electrical boxes, you might have to use PVC, "Bell" boxes (zinc or aluminum), or larger 'pull cans' made of stainless. Whatever you get, double-check the assorted screws, etc., for magnetic properties.
John120/240
Senior Member
- Location
- Olathe, Kansas
So looking through the window at the MRI machine ? All of that copper sheet
has to be expensive. Do light fixtures have any special requirements in these
locations ?
has to be expensive. Do light fixtures have any special requirements in these
locations ?
The top picture is inside of the magnet room, the bottom picture is the control booth
The copper is quite expensive and I am not sure why some use copper, some use alluminum, and although I have never seen one, I am told there are some using steel sheilding.
Except for Phillips all I have been involved with have required DC incandescent lighting.
The last Phillips I was involved with just called for 130V heavy duty lamps.
Roger
- Location
- Simi Valley, CA
Did one awhile back. I wasn't there, but I saw the after math. Guess the tile guy was in the room finishing up when they turned on the machine for it's initial set up. They asked the guy if the tile cutter was magnetic and he said no it was made of aluminum. They fired the machine up and they said the tile cutter started shaking and then jumped into the machine and started bouncing around and beat the bejebers out of the inside of the MRI machine. Seems that the screws in the tile cutter were steel.
renosteinke
Senior Member
- Location
- NE Arkansas
FYI ...
The copper won't do anything as to 'shielding' the magnetic field. Maybe that's why it was used. What copper sheathing WILL do is block radio waves of nearly every frequency- that is, be a 'Faraday cage.' Why this is necessary for the MRI machine is something only the designer knows.
Yes, you can 'shield' or 'direct' magnetic fields. That's exactly what the steel jacket of a fluorescent light ballast does.
For that matter, the metal used to make up the core of the ballast (as well as solenoids, coils, transformers, etc.) is specifically alloyed to increase its' magnetic properties.
The copper won't do anything as to 'shielding' the magnetic field. Maybe that's why it was used. What copper sheathing WILL do is block radio waves of nearly every frequency- that is, be a 'Faraday cage.' Why this is necessary for the MRI machine is something only the designer knows.
Yes, you can 'shield' or 'direct' magnetic fields. That's exactly what the steel jacket of a fluorescent light ballast does.
For that matter, the metal used to make up the core of the ballast (as well as solenoids, coils, transformers, etc.) is specifically alloyed to increase its' magnetic properties.
jfilipek02
New member
- Location
- South St Paul MN
non ferrous boxes
non ferrous boxes
I have confronted this same issue several times in the past: non ferrous junction boxes for MRI installations.
The PVC or fiberglass products did not meet the grounding requirements for critical care, there were also concerns about the fire ratings on these items not meeting the local code.
I have used steel boxes and aluminum conduit on 50+ MRI projects with no hesitation; but there has been increasing push from the MRI manufacturers to do away with ferrous materials all together. I have started using aluminum boxes that are custom manufactured; but it would be nice if there were a commercially available product.
Has anyone else experienced these same push backs?
Thanks- Jason
non ferrous boxes
I have confronted this same issue several times in the past: non ferrous junction boxes for MRI installations.
The PVC or fiberglass products did not meet the grounding requirements for critical care, there were also concerns about the fire ratings on these items not meeting the local code.
I have used steel boxes and aluminum conduit on 50+ MRI projects with no hesitation; but there has been increasing push from the MRI manufacturers to do away with ferrous materials all together. I have started using aluminum boxes that are custom manufactured; but it would be nice if there were a commercially available product.
Has anyone else experienced these same push backs?
Thanks- Jason
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