When centrifuging biohazards, it is recommended that the safety buckets and sealed rotors be:

How do I avoid centrifuge imbalances in the first place?

Ensure that your work surface is level and firm. Do not use the centrifuge on an uneven or slanted work surface.

At high speeds, a centrifuge can easily become unbalanced if equal masses are not located opposite each other in the rotor: 

For fixed-angle rotors, balance your tubes according to their weight. Load the rotor symmetrically and ensure the opposing tube is not only the same type of tube, but that it is also filled with the same mass. If the number of tubes with samples is uneven, counterbalance using water in an additional tube. Remember to balance the mass (weight) of the tubes, not the volume (size). Weigh the tube with your sample and record the mass. If you are spinning more than two tubes, only the tubes directly opposite each other have to be equal in mass.

For swing-out rotors, always load all rotor positions with buckets (incomplete loading of the rotor may reduce the lifetime of the rotor). The weight of the maximum load or maximum weight of the completely loaded bucket is specified (weight class) on the buckets. Do not exceed this weight. When loading the buckets, make sure the tubes or plates are placed symmetrically.

Always check to see that the buckets swing out smoothly. If they do not, clean the pivots and grooves and apply grease.

(The following has been adopted from the University of Minnesota Centrifuge Safety Fact Sheet.)

Centrifugation may present two serious hazards: mechanical failure and dispersion of aerosols.  This page describes safety and maintenance procedures to minimize centrifuge hazards.

General Procedures:

Before Centrifugation

• Train each operator on proper operating procedures, review the user manual.
• Use only rotors compatible with the centrifuge.
• Check the expiration date for ultracentrifuge rotors.  Check tubes, bottles, and rotors for cracks and deformities before each use.
• Make sure that the rotor, tubes, and spindle are dry and clean.
• Examine O-rings and replace if worn, cracked, or missing.
• Never overfill centrifuge tubes (don’t exceed ¾ full).
• Always cap tubes before centrifugation.
• Always balance buckets, tubes, and rotors properly.
• Check that the rotor is seated on the drive correctly, close the lid on the centrifuge, and secure it.
• When using swinging bucket rotors, make sure that all buckets are hooked correctly and move freely.

During Centrifugation

• Keep the lid closed at all times during operation. Never open a centrifuge until the rotor has stopped.
• Do not exceed safe rotor speed.
• The operator should not leave the centrifuge until full operating speed is attained and the machine appears to be running safely without vibration.
• Stop the centrifuge immediately if an unusual condition (noise or vibration) begins and check load balances.

After Centrifugation

• Allow the centrifuge to come to a complete stop before opening.
• Wear appropriate gloves to remove rotor and samples.
• Check inside of centrifuge for possible spills and leaks, clean centrifuge and rotor thoroughly if necessary.
• Wash hands after removing gloves.

Centrifuging Infectious Materials or Human Samples:

Safety procedures above plus:

• Place a biohazard label on the centrifuge.
• Always wear gloves when handling tubes or rotors.
• Avoid the use of celluloid tubes with biohazards.  If celluloid tubes must be used, an appropriate chemical disinfectant must be used to decontaminate them.
• Always use sealed safety cups, safety buckets, or sealed rotors with O-ring as secondary containment if available.

Fill centrifuge tubes, load into rotors, remove from rotors, and open tubes within a biological safety cabinet if biological safety cabinet is available.

• Wipe exterior of tubes or bottles with disinfectant prior to loading into rotor or bucket.  Seal rotor or bucket, remove outer gloves, and transport to the centrifuge.
• Always wait at least 10 minutes after the run to allow aerosols to settle before opening the centrifuge.  Check for possible spills or leaks.  For spills of infectious materials, see Emergency Procedures below.
• Decontaminate centrifuge interior, safety cups or buckets, and rotors if tube breakage occurs. See Emergency Procedures below.
• Include centrifugation procedure and decontamination plan in lab SOPs.

Emergency Situations.  The following events are considered an emergency:

• If there is a spill in the centrifuge
• If centrifuge malfunctions
• If there is rotor failure
• If there is tube breakage

Emergency Procedures:

• Turn centrifuge off immediately, close the centrifuge lid.
• Notify others, evacuate the lab, close the door, post a biohazard spill sign at the lab door.
• Leave for 30 minutes to reduce the risk of aerosols.  For spill clean-up, the operator should wear proper gloves, remove debris, clean and disinfect centrifuge interior, rotors, safety cups or buckets following the manufacturer’s instructions.
• Place any contaminated protective clothing, gloves and all clean-up materials in a biohazard bag.  Wash hands and any exposed skin surfaces with soap and water.  Call 911 or seek immediate medical attention if overtly exposed to recombinant or synthetic nucleic acid molecules or Risk Group (RG) 2 infectious agents.
• • Report incidents to P.I. or Lab Supervisor and call the CHO for assistance.

Centrifuge Maintenance:

Moisture, chemicals, strong cleaning agents, and other substances can promote corrosion of centrifuge parts and cause centrifuge failure.  The following are general maintenance recommendations:

• Follow manufacturer instructions for maintenance and cleaning.
• Keep the centrifuge clean and dry.
• Cleanup all non-infectious spills immediately.  For infectious spills see Emergency Procedures above.
• Decontaminate the rotor after use with biological or radioactive materials.  Use 10% bleach for 30 minutes followed by 70% ethanol and let air dry to clean rotors and cups.
• Never clean rotors and associated parts with abrasive wire brushes.
• Store the rotor upside down in a dry place, with lids or plugs removed, to prevent condensation.
• Remove adapters after use and inspect for corrosion.
• Inspect rotor regularly.  Remove rotors from use that show any sign of defect, and report it to a manufacturer’s representative for inspection.

Maintaining a Log Book:

To avoid rotor failure, keep a log book for high speed rotors recording the length of time and speed for each use.  Track and discard rotors according to the manufacturer’s recommended schedule.

When centrifuging biohazards What is the recommended wait time before opening the centrifuge to allow aerosols to settle?

Which of the following is a good practice when centrifuging biohazards?

When using the centrifuge what safety precautions should be followed?

What should not be done when using centrifuge?