Utility Requirements
H157654_9_011 77 / 120
8.9 Fire Detection System and Fire Extinguishers
Rooms containing NMR magnets should be equipped with temperature sensors for fire de-
tection. These must respond only to a sudden rise of temperature, and not be triggered by a
quench (sudden drop of temperature).
Optical smoke detectors cannot discriminate between smoke from a fire and fog from either a
helium refill or caused by a quench, so these may not be used. Combined heat and smoke
detectors are recommended instead.
Fire extinguishers in the vicinity of the magnet room must be non-magnetic (stainless steel
or aluminum). It is the obligation of the customer to inform the local fire department about the
dangers of magnetic fields. These magnets stay at field for a long time even in a most blazing
fire!
Ceiling sprinkler heads should be made of metal instead of glass. A quench could falsely
trigger the alcohol-filled glass vials, which can shatter in the presence of cold helium gas.
Sprinklers should not be located directly over the magnet.
Any sprinkler lines or other metal pipes located above the magnet should be thermally-insu-
lated to prevent O
2
condensation or water freezing in the line from the large amount of cold
He gas following a magnet quench.
A pre-action sprinkler system is recommended, as it is not loaded with water, but is acti-
vated through an interlock mechanism enabling the water to fill the lines in case of a fire.
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