Utility Requirements
68
H157655_1_008
8.7
Emergency Ventilation During Installation and Quenches
Due to the large amount of liquid helium contained in the magnet, an emergency exhaust
system may be required to prevent O
2
depletion during a magnet quench.
Likewise, during the installation, refilling and cooling of superconducting magnets, large
volumes of nitrogen or helium gases may be generated under certain conditions. Although
these gases are inert, if generated in large enough quantities, they can displace the oxygen
in the room causing potential danger of suffocation.
The following table lists the maximum helium capacity and the typical gas flow rates for
helium gas during a quench for current magnet systems. Generally, the gas flow rate is equal
to half the volume in one minute.
Total Volume of Gas and Maximum Helium Gas Flow
Magnet Type
Total Volume of He
Gas (m
3
)
Maximum He Gas
Flow (m
3
/min.)
400/54 Ascend Aeon
196.7
98.35
500/54 Ascend Aeon
182.0
91.0
600/54 Ascend Aeon
262.5
131.25
700/54 Ascend Aeon
230.3
115.15
Table 8.6:
Total Gas Volume and Maximum He Gas Flow: Standard Bore 54 mm
Magnet Type
Total Volume of He
Gas (m
3
)
Maximum He Gas
Flow (m
3
/min.)
400/89 Ascend Aeon
269.5
134.75
500/89 Ascend Aeon
262.5
131.25
600/89 Ascend Aeon
225.4
112.7
700/89 Ascend Aeon
236.6
118.3
Table 8.7:
Total Gas Volume and Maximum He Gas Flow: Wide Bore 89 mm
Regarding the emergency gas exhaust, important considerations include, but are not limited
to, the following:
•
Amount of liquid helium
: Taking the 750 WB US
2
magnet as an example, the total
amount of liquid helium is 473 liters. In case of a quench, the liquid transforms into gas
and expands by a factor of 740. Therefore, the total amount of helium evaporated gas in
case of a quench will be ca. 350 m
3
(12,360 ft
3
).
•
Maximum helium gas flow
: The maximum flow of helium gas is calculated on the
assumption that half of the volume of liquid evaporates in 1 minute, thus the maximum
flow would be 175 m
3
(6,180 ft
3
) for the 750 WB US
2
magnet. The gas should be removed
from the room immediately through an emergency exhaust system.
•
O
2
level sensors
: Oxygen level sensors are required to detect low O
2
levels within the
laboratory for each system. One sensor is needed above the magnet for detecting low O
2
levels due to He gas exhaust in case of a quench or during He fills. An additional sensor is
needed close to the floor for detecting low O
2
levels due to N
2
gas exhaust during magnet
cooling or regular N
2
fills. In case of placing the magnet inside a pit, a third sensor is
needed inside a pit to detect low O
2
levels from N
2
gas.
Summary of Contents for AVANCE
Page 6: ...Contents vi H157655_1_008 ...
Page 24: ...System Components 24 H157655_1_008 ...
Page 32: ...Magnet Access and Rigging 32 H157655_1_008 ...
Page 38: ...Ceiling Height Requirements 38 H157655_1_008 ...
Page 72: ...Utility Requirements 72 H157655_1_008 ...
Page 82: ...Floor Plan 82 H157655_1_008 ...
Page 96: ...CryoProbe and Other Accessories 96 H157655_1_008 ...
Page 102: ...Contact 102 H157655_1_008 ...
Page 104: ...List of Figures 104 H157655_1_008 ...
Page 109: ...H157655_1_008 109 ...
Page 110: ...Bruker Corporation info bruker com www bruker com Order No H157655 ...