MRI Room Alarms

From Bangor Imaging Unit

Don't Panic

Notice: We will update this page after the new alarm system is installed.


The Scanner Suite Environmental systems are connected to an alarm panel. Many faults in the system will trigger an alarm. Don't panic. Only the low oxygen alarm indicates possible immediate danger.

Low Oxygen


Low Oxygen Alarm Protocol
  1. Stop scanning and prepare to remove participant
  2. Open the door to the scanner suite and remove the participant. This may be a little difficult as the exhaust fan will have switched on and there will be negative pressure in the MRI room that you have to work against. Prop the door open. The combination of the open door and the exhaust fan should rapidly bring the O2 levels in the room back to equilibrium, and the Alarm should switch off.
  3. If the Alarm is still going, silence the alarm using the mute sounder button.
  4. If the alarm does switch off (red light on panel goes out) we now have to look for the cause of the initial O2 drop. Contact Paul Mullins and Andrew Fischer so we can have a look at the problem and ascertain if it is a Helium leak or some other environmental cause.
  5. If the alarm doesn't go off check the O2 numbers, and check that everyone is breathing Okay, and that no-ones lips are turning blue. This should ensure that the problem is not really related to O2 levels. If you do have difficulty breathing, or lips are turning blue, leave the scanner room if possible and close the door behind you - Get Paul or Andrew and be prepared to call security. If you can't leave the room, open the windows, call security and report the problem then call Paul Mullins or Andrew Fischer.
  6. If the alarm light stays on, even after checking for Helium or other gasses, it may be due to a faulty O2 sensor. The O2 sensor should last 12-18 months before needing to be replaced. If this is the case contact Paul or Andrew, who can recalibrate the sensor so it will work until a new sensor is ordered.
  7. If the alarm switches off, and the room does not appear to contain a helium leak, then you can continue to scan.

Mute Sounder

Pressing the MUTE SOUNDER button will silence the alarm. It is generally a good idea to mute the sounder immediately as the audio alarm makes it hard to use the intercom.

Emergency Extract Fan Running and Ventilation Fail

Together, these two alarms indicate the emergency ventilation system is in operation. When active, a powerful fan pulls air from the magnet room. At the same time the normal MRI room AC is isolated. The emergency ventilation system is activated either by a Low Oxygen Alarm or by rotating the test switch at the bottom of the panel to the test position. If the test switch is set to normal, assume there is a low oxygen alarm even if the Low Oxygen lamp is out. The Low Oxygen lamp might be faulty. Follow the Low Oxygen protocol above. If the switch is set to test, find out why before switching the emergency system off. There may be a helium leak or other reason why the fan is running.

Water Under Floor


If this alarm occurs:

  1. Mute the sounder.
  2. Stop scanning.
  3. Remove the participant from the magnet.
  4. Contact Paul Mullins and Andrew Fischer
  5. If Andrew and Paul are not available, contact Estates


There are high voltage cables under the floor of the technical room. To be safe, you may wish to disconnect the scanner from mains power before entering the technical room.

Emergency Electrical Disconnect

  1. Remove the participant from the scanner.
  2. Exit the scanner software and shut down the console computer.
  3. Wait for the computer to finish shutting down
  4. Push the Emergency Electrical Switch Off button.
  5. DO NOT TOUCH THE HELIUM VENT CONTROL.

Chilled Water Fault

Press the Mute Sounder button to silence the alarm. If you are scanning, prepare to end the scan. It will not be possible to scan until this fault is corrected. A Chilled Water Fault does not require emergency action.
Contact Paul Mullins and Andrew Fischer. When the cooling plant is out of operation for several days, the liquid helium around the magnet will gradually heat up and begin to boil off. To prevent this from happening, there is a a by-pass system using mains water to cool the helium compressor. If Andrew or Paul are not available, contact Estates. They should be able to correct the fault or switch over to the backup.

Technical Room A/C Unit Fault

Press the mute sounder button to silence the alarm. If you are scanning, prepare to end the scan. Technical Room A/C Unit Fault does not require emergency action. Contact Paul Mullins or Andrew Fischer. They may be able to resolve the issue quickly and allow you to resume your scan. Equipment in technical room requires cooling and may overheat without AC. Do not continue to scan until this alarm is resolved.
If Andrew or Paul are not available remove your subject from the scanner. After your subject has left, prop open the technical room door. Contact Estates.

Emergency Extract Fan Isolator Open

There is no protocol for this alarm.

Control Room A/C Unit Fault

This fault alone should not prevent continued scanning. Open a few windows if the control room becomes warm. Contact Paul Mullins and Andrew Fischer.

Filter Dirty

Contact estates - this alarm requires an A/C technician to come out and replace the A/C filter

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