Bruker BioSpec 117 AVANCE III, Manual

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22 ID: 182463115
Laboratory infrastructure and interactions
5.3 Interactions
The MR system and its surroundings may affect each other based on the following interactions:
▪ magnetic interactions
▪ electromagnetic interactions
▪ building vibrations and impact noise
▪ room air and cooling systems
A distinction must be made in these items between
▪
Standard specifications
: The maintenance of these values by the MR system and by all
the facilities in the vicinity of the system guarantees the safe operation of all systems and
facilities. See chapter
Standards [

15]
.
▪
Functional specifications of the MR system
: The maintenance of the functional specifi-
cations is necessary to guarantee the promised quality of the MR system. These specifica-
tions are usually more stringent than the standard specifications.
The following sections deal with the description of the
functional specifications
and
interac-
tions
.
See also Chapter
Mobile sources of magnetic disturbance [

23]
See also

Environmental conditions [ 
15]
5.3.1 Magnetic interactions
5.3.1.1 Ferromagnetic mass
The quality of the magnetic field of the MR system is negatively influenced by ferromagnetic ma-
terials located in the immediate vicinity of the magnet.
This interference is generally caused by magnetic building materials in the immediate vicinity of
the magnet. All ferromagnetic materials in the building structure must be considered, e.g.:
▪ Steel reinforcements in floors and walls
▪ Pipelines
▪ Structural steel and reinforcements
▪ Heating elements
▪ Steel doors and steel window frames
▪ Crane rails and hanging trolleys
▪ Sub-structures
Limit value of ferromagnetic mass density:
If there are floors or walls in areas that lie within the area defined by the 0.5 mT stray field
strength, the ferromagnetic mass density may not exceed the limit value of 100 kg/m
2
.