(updated 25/2/22)
1. Hazards & Risks in NMR Facilities
Nuclear Magnetic Resonance (NMR) Spectroscopy and Imaging Facilities are classed as hazardous areas for the following reasons:
- The magnetic fields produced by superconducting NMR magnets exert strong attractive forces on ferromagnetic objects. Depending on how large the object is and how close it is to the magnet, the attractive force could be great enough to uncontrollably draw the object towards the magnet, possibly at some speed. Anyone caught between the magnet and the projectile could sustain life threatening injuries. The equipment itself may also be seriously damaged by the impact. If the ferromagnetic object is inside the body, e.g. surgical implants containing ferromagnetic material, the risk of fatal injury is far greater. In addition to causing implants to move, certain types of magnetic field can also cause implants to heat up. Note: the ferromagnetic object has to be in very close proximity to the magnet for these adverse events to occur.
- Electronic, electrical or mechanical surgical implants, e.g. pacemakers, neurostimulators or biostimulators, may be adversely affected or even stopped by magnetic fields as low as 5 gauss.
- Items such as magnetic storage media, computers, cameras and watches may be irreparably damaged if exposed to fields above 10 gauss. Electrical transformers may be affected by fields greater than 50 gauss.
- The magnets are housed in cryostats that contain large volumes of cryogenic liquids. If an accident or system failure occurs that allows the uncontrolled escape of these liquids (known as a quench) the volume of gas produced could reduce the oxygen concentration in the room down to levels that could cause rapid asphyxiation.
General Risk Assessment 160 gives further details on the hazards and risks encountered in NMR Facilities. If you intend to carry out a work related task in an NMR Facility you must read this assessment and sign the hard-copy kept in the NMR Facility.
2. Restricted Areas
In SLS, NMR Facilities are housed in clearly signed, restricted access areas. In normal circumstances, all persons requiring access to these restricted areas must complete an NMR Safety Questionnaire. There is no other mechanism for obtaining authorised access. The only people who do not have to complete a questionnaire are those making a one-off visit and those requiring access to deal with an emergency situation, e.g. Firemen, engineers, E&B staff, providing they are accompanied by an authorised person at all times. The authorised person takes responsibility for the safety of anyone they allow into the restricted area.
The NMR labs in the JBC basement have proximity card operated doors. In order to get your proximity card enabled for these doors you must complete an NMR Safety Questionnaire, get it signed off by a member of NMR Facility Staff or SLS Safety, then hand it over at DC Reception.
If you answer "no" to all questions on the NMR Safety Questionnaire, once your completed questionnaire has been processed, your proximity card will automatically be enabled for the JBC NMR lab doors.
If you answer "yes" to any of the questions on the NMR Safety Questionnaire, there is a possibility that you may be adversely affected in certain zones within the restricted area. This does not mean that you will automatically be banned from entering the restricted area, but it does mean that you will require specific, one-to-one training and instruction, from NMR Facility Staff or SLS Safety, before being granted access. Once your completed questionnaire has been processed you will receive a letter from SLS Safety giving further information specific to your case.
SLS Safety will keep: all completed NMR Safety Questionnaires; a register of all those who have completed and returned a questionnaire; copies of all correspondence relating to completed questionnaires.
3. The 5 Gauss Zone
This is the zone where the magnetic field is at a strength of 5 gauss or more. It is demarcated by hazard tape and warning signs. Only fully trained personnel are permitted to work within a 5 gauss zone.
5. Other Information