All Columiba NMR users should read and be familiar with the following safety information.  There are multiple potential hazards in the NMR laboratory.

 

Columbia’s NMR instruments use large superconducting magnets that are housed in a cryostat containing liquid helium and liquid nitrogen.

 

Magnetic Field Hazards

Magnets will exert large attractive forces on equipment or other magnetic objects when brought close.  The force may become large enough to move the equipment uncontrollably towards the NMR magnet.  Small pieces of metallic subjects (wrenches, screwdrivers...) may become projectiles. Large equipment (gas cylinders) can cause bodies or limbs to become trapped between the equipment and the magnet.  Keep in mind the following:

The closer to the magnet, the larger the force.

The larger the mass, the larger the force.

Remember: Superconducting magnets are ALWAYS on

 

Here and here you can see a video of a demonstration of what happens when you get a heavy iron object too close to a magnet.

 

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Medical Implants

The operation of electronic,electrical or mechanical medical implants, such as cardiac pacemakers, biostimulators, and neurostimulators may be affected or even stopped in the presence of either static or changing magnetic fields.  Medical implants such as aneurysm clips, surgical clips or protheses may contain ferromagnetic materials and therefore would be subjected to strong attractive forces near the magnet. This could result in injury or death. Additionally, in the vicinity of rapidly changing fields (pulsed gradient fields), eddy currents may be induced in the implant resulting in heat generation. 

 

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Cryogen Hazards

Cryogens such as liquid nitrogen (LN2) and liquid helium that are present in the magnet cryostat and portable dewars may pose several dangers, including asphyxiation, frostbite  and chemical explosions.  A) When a magnet quenches, or suddenly becomes non-superconducting,  large amounts of liquid cryogens are quickly vaporized. Here is a video of a magnet quenching. Due to their large expansion ratios (nitrogen 695:1, helium 760:1), these gases can quickly displace all the oxygen in the NMR room and cause asphyxiation. Effects from oxygen deficiency become noticeable at levels below ~18% and sudden death may occur at ~6% oxygen content by volume. B) Direct contact with cryogenic substances in liquid or vapor form can produce “cold burns” on the skin similar to conventional burns.  The temperature of liquid helium is -269 C and of liquid nitrogen is -196 C.  C) Cryogenic fluids with a boiling point below that of liquid oxygen are able to condense oxygen from the atmosphere. Repeated replenishment of the system can thereby cause oxygen to accumulate. Violent reactions, e.g. rapid combustion or explosion, may occur if the materials, which make contact with the oxygen, are combustible.

 

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NMR Tube Safety

NMR tubes have thin walls and are easily broken.  Once broken, they are extremely sharp. When inserting NMR tube into spinner, grap the tube close to the spinner.  This will avoid applying a torque that can easily break a tube and, often, drive it into a finger.

 

Chemical Safety- Hazardous and dangerous materials

All users who conduct experiments with hazardous materials, including toxic and radioactive materials, including pressurized, explosive, or otherwise unusually hazardous materials must closely follow Columbia Environmental Health and Safety guidlines. Failure to do so may jeopardize the environment and safety of all users and may lead to suspension of facility access privilege and payment of any cleanup cost.

 

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In Case of Emergency:

Dial 99 from any campus phone, or 212-854-5555 for campus assistance.  It is your responsibility to report any accident to the NMR technical personnel immediately.