1. Safe Use and Operation of Vacuum Lines, UCLA Chemistry and Biochemistry2. http://www.monash.edu.au/ohs/topics/hazard-alerts/vacuum-pumps-cold-traps.html

VACUUM SAFETYJULY 26, 2011

STARTING UP• Ensure that the vacuum trap is dry and clean.• Lower the trap into the empty Dewar.• Ensure that all valves are closed, and start (or

open line to) the vacuum pump.• Fill the Dewar with liquid nitrogen and wrap the

top with a towel.

• Make sure all vessels attached to the line are under nitrogen.

• Carefully lower the Dewar and turn the pump off.

• Vent the system to air and wait for any frozen liquid to thaw.

• Dispose of any solvent.

SHUTTING DOWN

• Notify all laboratory personnel.• Wear a face shield, fastened lab coat and

thick rubber gloves.• Lower the Dewar and vent the system.• Carefully place a safety shield around the

trap. Do not attempt to remove.• Leave cold trap to stand overnight vented to

air and then carefully re-inspect to check that all suspect material has evaporated.

IF LIQUID O2 IS PRESENT

• NEVER let the trap sit in liquid nitrogen for more than a minute without having the vacuum pump turned on.

• Under NO circumstances should the system be left open to air with the Dewar containing liquid nitrogen in place.

FINAL WORDS