Helium flow and low oxygen alarms


As a reference, here is a description of the possible alarms in the MEG lab, and what to do if they activate. There will also soon be a lab safety section placed in the MEG lab manual binder at the acquisition desk.

  1. Fire alarm. There are audible and visual alarms in case of fire. There is also an announcement of “code red” throughout The Neuro in that event, indicating the location of the emergency. A code red is a standby alert, not a signal to evacuate, unless you feel in danger. Any order to evacuate will be a code green, with specific instructions provided over the PA.
    (The Neuro emergency procedures for code red and other codes are posted in the MEG lab near the phone.)

  2. Low oxygen alarm. This is a continuous high-pitched tone, coming from the oxygen sensor box on the wall near the helium cylinders (now behind the MEG electronics rack). The box also displays the oxygen levels in the shielded room. It triggers below 19.5% O2 (normal levels are 21%). If this happens, calmly evacuate the shielded room and the MEG suite, and close the suite door. (It is not necessary to close the shielded room door.) Inform Marc of the situation. If Marc is not on site, please place a sign on the door indicating not to enter while the alarm is sounding. (I will make a sign soon for that purpose and keep it on the inside of the door.) Finally, if you were not able to reach Marc, please call 5555 and indicate that there is a helium leak in NWB216 and that no further action is needed but that no one should enter until the alarm stops.

  3. Helium flow alarm. This is a regular beeping high-pitched tone coming from the flow meter besides the oxygen sensor box. It indicates how much helium gas is coming out of the MEG system. If it is lower or higher than set thresholds, it starts beeping and the corresponding red light will flash instead of being on continuously. This could indicate a problem with the MEG, though it can sometimes happen when moving the dewar in some situations. Marc should be informed (call or email if he is not on site) so he can investigate. It is ok to turn off the alarm by simply unplugging the power cable on the side of the flow meter. It is ok to continue using the MEG, unless the flow is so high that the orange ball is all the way to the top and the MEG was put horizontal. In that case, it is best to bring the MEG back to vertical and wait for Marc to investigate.

Marc’s contact info is posted in the lab near the phone, in the MEG lab manual binder, and on the lab door.