Use Autoclaves Safely
One of the most effective decontamination controls is steam sterilization
through the use of an autoclave. This process generates pressurized steam
within a sealed chamber. Autoclaves can sterilize all items that are
heat stable (not damaged by steam or high temperature).
- Gravity
autoclaves may require cycles of 250 degrees F (121
degrees C), 15 to 18 lbs. pressure for one hour to properly decontaminate.
- Newer vacuum autoclaves may require 270 degrees F (132 degrees
C), 27 to 30 lbs. pressure for 45 minutes.
- Use
a biological indicator to verify your autoclave
technique. Contact the Office of Environmental Health and Safety
for more information on the biological indicator test.
- REMEMBER:
Personal protective equipment (PPE) such as rubberized
aprons, full face shield and heat and liquid resistant
gloves must be worn when operating autoclaves.
Considerations
and Limitations of Autoclaves
Whatever
the temperature and time requirement for decontamination, the contents
of each autoclave load must be positioned so that steam penetrates into
and among all items to be decontaminated.
*
Tightly sealed or stoppered materials may not be effectively
decontaminated and may become dangerously pressurized causing injury when
removed.
A routine autoclave maintenance program is recommended. Regular
chemical "tape" monitoring
of temperature and periodic biological monitoring should be performed
to evaluate the effectiveness of the autoclave. Biological indicators
placed inside the load, the area slowest to heat up, and throughout the
autoclave are the best indication of sterilization. Call OEHS for assistance
in testing your autoclave.
NEVER place
items containing chemicals in an autoclave. Always
remove chemicals first.
DO
NOT autoclave celluloid (cellulose nitrate) tubes as they
are highly flammable and explosive in an autoclave.
*Bagged
waste from BL2+ or BL3 experiments should be sealed
before removal from the biosafety cabinet. For
this waste, carefully add water to the bag before sealing.
Use 50 ml for a small bag and 200 ml for a large bag.
The water will generate steam within the bag during the cycle.
