Bruker NMR AVANCE NEO Systems, User Manual, Page: 23 / 48

Magnet Safety
H171764_6_001 23 / 48
4.1.5 Before Ramping the Magnet to Field
Prior to start energizing the magnet system, one must:
• Ensure all loose ferromagnetic objects are removed from within 5 gauss field of the NMR
magnet system.
• Display magnet warning signs at all points of access to the magnet room.
• Display warning signs giving notice of the possible presence of magnetic fields and of the
potential hazards in all areas where the field may exceed 5 gauss.
4.1.6 After Ramping the Magnet to Field
After energizing the magnet to field, one must:
• Not bring ferromagnetic objects into the magnet room.
• Use only nonmagnetic cylinders and dewar for storage and transfer of compressed gas or
cryogenic liquids.
• Use only non-magnetic equipment to transport cylinders and dewar.
It should be noted that the magnet, once charged to field, cannot be switched off so that the
strong magnetic field disappears. Switching off the main electricity supply will have no effect
on the magnet and the strong magnetic field remains present.
4.1.7 General Safety Precautions
To prevent situations as described above to occur, the following precautions are provided as
guidelines, and they should be regarded as minimum requirements.
• Every magnet site location should be reviewed individually to determine the precautions
needed to be taken against these hazards.
• Consideration must be given to floors above and below the magnet as well as the
surrounding space at the same level, since the magnetic field produced by the NMR
magnets is three dimensional.
4.2 Controlled Access Area
For equipment that generates a stray field exceeding 0.5 mT (5 Gauss) outside its
permanently attached cover, and/or an electromagnetic interference level that does not
comply with IEC 60601-1-2, a Controlled Access Area must be defined and permanently
installed around the equipment such that outside this area:
• The magnetic fringe field strength shall not exceed 0.5 mT (5 Gauss).
• The electromagnetic interference level complies with IEC 60601-1-2:2001.
The stray field plots for the various magnets can be found in the corresponding magnet
manual. These plots indicate the position of the 0.5 mT (5 Gauss) line.
The Controlled Access Area shall be delimited, e.g. by markings on the floor, barriers and/or
other means to allow the responsible staff to adequately control access to this area by
unauthorized persons.
The Controlled Access Area should be labelled at all entries by appropriate warning signs,
including an indication of the presence of magnetic fields and their attractive force or the
torque on ferromagnetic materials.