Compression fittings for Aluminum EMT

[mshields]

I just was informed by an electrician working on a job for which I am the engineer, that the Aluminum EMT we are requiring in an MRI room (for it's non-ferrous properties) needs to be interconnected via steel compression fittings; that they do not make aluminum compression fittings.

Indeed I'm having a difficult time finding such a thing. Is it true?

Mind you, I don't think the pull from the magnet on fittings installed in the ceiling is a realistic concern. Still, I was surprised to hear this.

Thanks,

Mike

 

[GoldDigger]

You can probably find stainless steel (non-ferromagnetic), but for big bucks.

Sent from my XT1585 using Tapatalk

 

[jumper]

Are not die cast fittings made out of zinc and therefore would not be non ferrous and non magnetic?

This says the material is zinc or is it an alloy?

http://www.cooperindustries.com/con...log-pdfs/compression-fittings-zincdiecast.pdf

 

[gadfly56]

Are not die cast fittings made out of zinc and therefore would not be non ferrous and non magnetic?

This says the material is zinc or is it an alloy?

http://www.cooperindustries.com/con...log-pdfs/compression-fittings-zincdiecast.pdf

Is the ferrule steel?

 

[hbiss]

Never heard of aluminum EMT. I would say go with cast set screw fittings but I'm thinking a set screw is no good with soft aluminum much the same way that set screw connectors are not allowed with aluminum MC or AC. How about using rigid aluminum? How much is there? Probably would cost less to cut and thread than stainless fittings.

-Hal

 

[hbiss]

Is the ferrule steel?

As I remember it is.

-Hal

 

[jumper]

Is the ferrule steel?

IDK, ask Mr. Cooper.

 

[gadfly56]

I just was informed by an electrician working on a job for which I am the engineer, that the Aluminum EMT we are requiring in an MRI room (for it's non-ferrous properties) needs to be interconnected via steel compression fittings; that they do not make aluminum compression fittings.

Indeed I'm having a difficult time finding such a thing. Is it true?

Mind you, I don't think the pull from the magnet on fittings installed in the ceiling is a realistic concern. Still, I was surprised to hear this.

Thanks,

Mike

There is at least one report of an steel oxygen tank having been brought into an MRI room and on activation of the MRI the tank flew into the ring. There was a small child on the bed at the time. He did not survive. Items as small as paper clips or hairpins have caused patient injury. I'd err on the side of caution.

 

[Carultch]

Is the ferrule steel?

The ferrule is ferrous steel. I just checked one with a magnet.

The zinc body and locknut are not ferrous. It probably isn't elemental zinc, but whatever it is, the dominant ingredient of die cast is zinc.

 

[steve66]

There is at least one report of an steel oxygen tank having been brought into an MRI room and on activation of the MRI the tank flew into the ring. There was a small child on the bed at the time. He did not survive. Items as small as paper clips or hairpins have caused patient injury. I'd err on the side of caution.

Yes, I remember reading about that.

You can also watch videos on youtube of someone throwing a wrench (or something similar) into an MRI. Its very cool to watch. The wrench just keeps flying back and forth through the MRI bore.

But metal parts that are securely anchored in place usually aren't a problem. I've never specified anything other than the usual EMT.

What would you do about boxes if you tried to get rid of all the steel? And the hangers and supports? Even outlets will probably have some steel in them. And I believe the wall studs are usually steel also.

 

[mshields]

thanks for the input

thanks for the input

I'm not going to allow it.

By the way, the whole problem came to light because of a "manufacturer" who won't allow aluminum MC cable. The owner actually bought these fixtures from someone other that who we specified, so not my problem.

We normally use AL MC cable for normal fixtures and AL EMT for Critical branch fixtures with 6 foot whips of Al FMC to the fixtures.

This manufacturer and I don't think they know what they are doing. In fact, I think they have these contract manufactured. Their install manual is riddled with errors.

They are insisting that all wiring whether normal or critical branch and including the final connection to the fixtures be with solid conduit.

Does this sound odd to you?

 

[K8MHZ]

I think rigid aluminum has all aluminum fittings.

 

[Fulthrotl]

Never heard of aluminum EMT. I would say go with cast set screw fittings but I'm thinking a set screw is no good with soft aluminum much the same way that set screw connectors are not allowed with aluminum MC or AC. How about using rigid aluminum? How much is there? Probably would cost less to cut and thread than stainless fittings.

-Hal

.
i'd vote for aluminum rigid conduit. it comes with aluminum couplings.
but..... straps, j boxes, covers, etc. i've never seen aluminum straps....

aluminum isn't that expensive, and it cuts and threads pretty quickly
with a porta pony.

 

[roger]

FWIW, I have always used steel EMT within the walls of an MRI room, this includes GE, Philips, Hitachi, and Siemens. Some MRI's even use steel envelopes (I have never been involved with one of these though) The main concern is that the ferrous metal is secured.

Overhead I always used aluminum flex.

All of this was per the manufacturers drawings and specs

Roger

 

[Rampage_Rick]

There is at least one report of an steel oxygen tank having been brought into an MRI room and on activation of the MRI the tank flew into the ring.

The stronger magnets are always on. The electromagnets used to tweak the main field are exponentially less powerful. Turning off the superconducting magnet is a very expensive endeavor requiring engineers and special "ramp down" equipment, or a big red button that could possibly damage the machine... (google "magnet quench")

There is another case where an oxygen tank was brought in by accident when an orderly was asked to bring in an oxygen mask.
Two workers were pinned for four hours because the big red button was disconnected.

For fun:

 

[Carultch]

.
i'd vote for aluminum rigid conduit. it comes with aluminum couplings.
but..... straps, j boxes, covers, etc. i've never seen aluminum straps....

aluminum isn't that expensive, and it cuts and threads pretty quickly
with a porta pony.

Stainless straps are non-ferrous, and accomplish the same intent.

 

[iwire]

The stronger magnets are always on. The electromagnets used to tweak the main field are exponentially less powerful. Turning off the superconducting magnet is a very expensive endeavor requiring engineers and special "ramp down" equipment, or a big red button that could possibly damage the machine... (google "magnet quench")

There is another case where an oxygen tank was brought in by accident when an orderly was asked to bring in an oxygen mask.
Two workers were pinned for four hours because the big red button was disconnected.

For fun:

That is all well documented but we are not talking about loose items being brought into the room after the magnet is operational.

The studs are steel, I bet the screws holding the wall finish to the studs are steel. Why would EMT have to be treated differently?