NMR Safety Guidelines

Please read this page before entering the NMR rooms.

Before beginning work in the NMR Facility,
users must complete the Safety Acknowledgment Form.


WARNING
Exposure to strong magnetic fields can cause serious injury or death
and significant damage to personal property, equipment and data.

5-Gauss Perimeter for our NMR Spectrometers
Frequency
Bore
Radial distance
Axial Distance
Location
500 MHz
51 mm
2.8 m (9.2 ft)
3.6 m (11.8 ft)
3608 PSBN
400 MHz
54 mm
2.2 m (7.2 ft)
2.8 m (9.2 ft)
3608 PSBN
200 MHz
51 mm
1.5 m (4.9 ft)
1.5 m (4.9 ft)
2670 PSBN
  1. Individuals with medical devices (e.g. cardiac pacemakers and metal prostheses) must remain outside the 5-gauss perimeter. The NMR spectrometers generate strong magnetic fields that can affect the operation of some pacemakers and harm implanted or attached devices, such as prosthetic parts and metal blood vessel clips. Persons with these types of medical concerns should contact their physicians about the possible health risks before entering the Facility.

    2.
  2. Floppy disks, tapes, cards with magnetic strips, cellular phones, laptops and mechanical watches should remain outside the 5-gauss perimeter. Strong magnetic fields surrounding the NMR spectrometers can damage the strip of magnetic media found on credit cards, ATM cards, driver's licenses, and other kinds of cards. Floppy disks, tapes, cellular phones, and laptop computers are also susceptible to damage inside this perimeter. Mechanical wrist and pocket watches will also malfunction and be permanently damaged when exposed to a strong magnetic field.

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  3. Metal objects must remain outside the 5-gauss perimeter. Strong magnetic fields surrounding the NMR spectrometers attract objects containing steel, iron, and other ferromagnetic materials. This includes most ordinary tools, electronic equipment, compressed gas cylinders, steel chairs, and steel carts. Unless restrained, such objects can suddenly fly toward the magnet which can cause personal injury and extensive damage to the probe, dewar, and superconducting solenoid. The greater the mass of the object, the more strongly it is attracted by the magnet. Only non-ferromagnetic materials should be used near the instruments.

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  4. The magnet/dewar has a high center of gravity and could tip over in an earthquake or if struck by a large object. In addition to serious injuries to persons near the magnet, the sudden release of nitrogen and helium gases from the dewar will displace breathable oxygen in the room. The 500 MHz and 400 MHz instruments are supported by anti-vibration legs that are bolted to the floor. The 400 MHz NMR is further supported with ropes suspended from the ceiling. The 200 MHz NMR is supported by the attached sample changer.

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  5. In the event of a "magnet quench," leave the room immediately and contact the NMR Facility Staff. A quench refers to the sudden release of gases from the dewar. Rapid expansion of liquid helium or nitrogen to gas can displace breathable oxygen in an enclosed space creating the possibility of asphyxiation. Do not re-enter the room until the oxygen level has returned to normal.

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  6. Only individuals who have had special training should transfer liquid helium and nitrogen to the instruments. Handling cryogens is dangerous and can cause serious burns. Safety glasses and gloves should be worn during the transfer of all cryogens.

    7.
  7. Do not exceed the boiling or freezing points of your sample. A sample subjected to a temperature change can build up excessive pressure which can break the tube. Broken glass, projectiles and hot or toxic chemicals can cause injury. To avoid this hazard, establish the freezing and boiling points of a sample before doing a variable temperature experiment, and never rapidly heat or cool a sample. Always wear safety glasses near the magnet when performing variable temperature experiments.

    8.
  8. Be very careful with sample tubes as they are fragile and break easily. The top of the sample tube can break off when the probe is removed. The sample should be ejected before removing the probe from the magnet. Use extreme caution when removing the probe if the sample cannot be ejected.

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  9. Do not operate the NMR spectometers in the presence of flammable gases or fumes. Flammable gases or fumes create the risk of injury or death from inhalation, fire and explosion.

    10.
  10. Do not look down the upper barrel of an NMR spectrometer if a probe is in place. Pneumatic ejection of a sample from the probe could cause injury.

The NMR Facility Manager can be reached at shirazi@chem.ucsb.edu