Nuclear Magnetic Resonance Instrumentation
NMR Instrumentation Safety Program
Nuclear magnetic resonance (NMR) instrumentation presents hazards associated with the strong static magnetic fields, cryogenic liquids and gases, and high electrical voltages/radiofrequency (RF) sources. The university operates multiple NMR spectrometers equipped with superconducting magnets. Some magnets are actively shielded to reduce the extent of their fringe magnetic fields; however, hazardous magnetic fields may still be present. strong magnetic fields remain present at all times. NMR magnets remain energized at all times, even when the spectrometer console or computer is turned off.
A 5-gauss perimeter will be physically marked if it encroaches on any active workspace or walkway.
NMR hazards are minimized through appropriate engineering controls, restricted access, user training, and adherence to established NMR facility procedures. Access to NMR magnet rooms and operation of NMR instrumentation are limited to individuals who have received appropriate training and authorization from the NMR Director and/or Facility manager.
NMR Hazards
- No person may operate NMR instrumentation without proper training and authorization from the NMR Director and/or Facility Manager.
- Users must not remove instrument covers or access electrical panels, RF amplifiers, power supplies, consoles, or other internal electrical components.
- Installation, servicing, troubleshooting involving internal components, and electrical repair may be performed only by appropriately qualified and authorized personnel.
- Users should immediately report electrical problems, unusual odors, smoke, damaged cables, or other suspected equipment malfunctions to NMR Facility Manager.
- Any accumulation of water or other liquid on the laboratory floor must be reported immediately to the NMR Facility Manager. Users should remain clear of wet areas, particularly in the vicinity of electrical equipment, until the hazard has been corrected.
Superconducting NMR magnets contain liquid helium and liquid nitrogen. Cryogenic liquids can cause severe cold burns or frostbite. Rapid evaporation of cryogens can also displace oxygen and create an oxygen-deficient atmosphere.
- Only individuals trained and authorized in cryogen handling may transfer or otherwise work directly with cryogenic liquids.
- Cryogen transfers must be performed in accordance with NMR facility procedures and with knowledge of the NMR Facility Manager.
- Appropriate personal protective equipment must be worn during cryogen handling. This includes a lab coat, long pants, closed-toed shoes, cryogenic gloves (gloves designed for cryogenic handling), and eye protection.
- Never place cryogenic liquids in a sealed container or otherwise prevent expanding gas from venting safely.
- Any accidental exposure to cryogenic liquids must be reported to the NMR Facility Manager and the Director of Environmental Health & Safety. DEHS: 502-852-6670
- NMR laboratory doors can be propped open if this is specifically allowed by the procedure or directed by authorized personnel.
- Oxygen monitors are installed in NMR magnet rooms where required to detect potentially hazardous decreases in oxygen concentration. Users must immediately leave the area if an oxygen-deficiency alarm activates. Do not enter the room if the oxygen alarm is active.
A magnet quench occurs when a superconducting magnet loses superconductivity and stored cryogenic liquid, particularly liquid helium, rapidly vaporizes. The resulting gas can displace oxygen in the room and create an asphyxiation hazard.
If a quench occurs or is suspected:
- Evacuate the magnet room immediately.
- Do not remain in the room to investigate the source of the gas release.
- Warn others not to enter the affected area.
- Follow the building emergency procedure and notify the NMR Facility Manager and emergency personnel as appropriate.
- Do not re-enter the room until authorized personnel have determined that it is safe.
Superconducting NMR magnets generate very strong static magnetic fields that are present continuously, including when the spectrometer console or computer is turned off.
Strong magnetic fields can exert very large attractive and rotational forces on ferromagnetic objects. Such objects can rapidly accelerate toward the magnet and become dangerous projectiles capable of causing severe injury or death and significant equipment damage.
- No person may enter an NMR magnet room without appropriate authorization and safety training
- Ferromagnetic or potentially ferromagnetic objects must not be brought into an NMR magnet room unless specifically approved by the NMR Facility Manager.
- ASSUME ANY METALLIC OBJECT IS MAGNETIC UNTIL PROVEN OTHERWISE.
- Examples of potentially hazardous objects include tools, gas cylinders, carts, chairs, keys, pocketknives, scissors, magnetic equipment, and electronic devices containing ferromagnetic components.
- Personal items such as keys, watches, phones, wallets containing metal objects, jewelry, hair accessories, and other potentially magnetic objects should be left outside the magnet room unless specifically approved.
Only approved non-magnetic tools and equipment may be used near an NMR magnet.
High-pressure gas cylinders must never be brought into an NMR magnet room unless they are specifically designed or verified for use in that environment and approved by the NMR Facility manager.
Certain implanted medical devices or metallic foreign bodies may interact with strong magnetic fields or may malfunction in a magnetic environment.
Anyone with a pacemaker, implantable cardioverter-defibrillator, neurostimulator, cochlear implant, other implanted electronic device, metallic implant, surgical clip, or known metallic foreign body must notify the NMR Facility Manager before entering an NMR magnet room or other controlled magnetic-field area.
Entry will be determined according to the device or implant's known magnetic-resonance safety status and NMR Facility policy. Devices with unknown safety status should not be assumed to be safe.
AS A GENERAL RULE, PERSONS WITH SUCH MEDICAL DEVICES MUST STAY OUTSIDE OF THE 5-GAUSS LINE.
If an object becomes attached to an NMR magnet:
- Do not attempt to remove the object yourself.
- Keep other personnel away from the magnet.
- Notify the NMR Facility Manager immediately.
- If an individual is injured or trapped, contact emergency services and follow NMR Facility emergency procedures.
For any suspected magnet quench, oxygen-deficiency alarm, fire, electrical emergency, or other immediate threat to personnel, evacuate the affected area and follow University emergency procedures.
NMR Safety Rules
Keep all ferromagnetic or potentially ferromagnetic objects outside of all Nuclear Magnetic Resonance (NMR) spectroscopy laboratories.
Superconducting NMR magnets generate extremely strong magnetic fields. The magnet is ALWAYS ON. Turning of the spectrometer console, computer, or other electronics does not turn off the superconducting magnet.
The following safety rules apply to anyone entering or working in an NMR laboratory:
- Medical implants and metallic foreign bodies. Anyone with a pacemaker, implanted electronic device, or other types of medical implants must notify the NMR facility manager before entering the room with the superconducting magnet.
- All ferromagnetic objects must be kept outside the NMR laboratory. This includes keys, wallets containing metal objects or magnetic-stripe cards, pocketknives, tools, etc. ASSUME ANY PIECE OF METAL IS MAGNETIC UNTIL PROVEN OTHERWISE.
- Keep electronics outside of the NMR laboratory unless approved by the NMR facility manager. Electronics may contain ferromagnetic components and may also be damaged or malfunction in strong magnetic fields.
- Use only non-magnetic tools inside the NMR laboratory.
- Access to the NMR laboratory is restricted. No individuals may be present within any NMR laboratory unless they have read and signed this safety form AND are present with the knowledge and explicit approval of NMR Facility staff.
- Do not bring ferromagnetic equipment into a controlled magnetic-field area without approval. The NMR facility manager must be notified prior to use of ferromagnetic objects within the 5-gauss line or any other magnetic-field safety boundary. Approval will be given on a case-by-case basis.
Strong magnetic fields can generate large attractive forces on ferromagnetic objects. Objects such as tools, high-pressure gas cylinders, pocketknives, carts, key rings, and most electronics can become dangerous projectiles if brought too close to the magnet. A ferromagnetic object can accelerate rapidly toward the magnet with great force and may cause severe injury or death to anyone in its path. An object striking the magnet can also cause serious and expensive damage to the magnet and associated equipment.
If any object becomes attracted to or strikes the NMR magnet, DO NOT attempt to remove it yourself. Leave the immediate area and notify the NMR facility Manager immediately.
A magnet quench occurs when the superconducting magnet loses superconductivity, causing liquid helium to rapidly boil into gas. The rapidly expanding helium can displace oxygen from the room and create a serious asphyxiation hazard. Escaping cryogenic gas can also cause cold injury or frostbite.
Signs of possible quench may include visible vapor or fog, unusual or loud gas discharge, or rapid release of cryogenic gas from the magnet or its venting system.
If a magnet quench is suspected:
- Leave the magnet room immediately
- Do not attempt to investigate or stop the quench
- Warn other not to enter the room
- Notify the NMR facility manager
- Do not re-enter the magnet room until it has been declared safe
5-Gauss line – The 5-Gauss line is the location around an NMR magnet where the static magnetic-field strength is 5 gauss (0.5 mT). It has traditionally used as a boundary for controlling access around superconducting magnets. The position of the 5-gauss line depends on the magnet and its shielding and may extend beyond the physical magnet room. Posted magnetic-field boundaries and NMR facility instructions must be followed.
Medical implants, electronic – Electronic medical implants (such as pacemakers) may be affected by strong magnetic fields. These devices can be either magnetic-field safe, conditionally safe, or unsafe. Anyone with an implanted electronic medical device must notify the NMR facility manager and receive clearance before entering an NMR magnet room or other controlled magnetic-field area.
Medical implants, non-electronic - Metallic implants such as pins, surgical clips, etc. may be magnetic and maybe subject to the same forces described above. Anyone with a metallic implant or known metallic foreign body must notify the NMR facility manager and receive clearance before entering an NMR magnet room or other controlled magnetic-field area.
Wallets, credit cards, watch, magnetic media - While not strictly a safety issue, large magnetic fields can wipe out the magnetic information on ATM and credit cards and magnetic media like computer discs. Keep your ATM and credit cards and magnetic media outside the 5-gauss line. Mechanical watches may also be permanently affected by large fields and thus should also be kept outside the 5-gauss line. Digital watches are usually okay within high magnetic fields, although some may have magnetic material. Each user is responsible for knowing if their watch is magnetic.