Autoclave Validation

Chemical Indicators

Tape Indicators

Tape indicators are adhesive-backed paper tape with heat sensitive, chemical indicator markings.  Tape indicators change color or display diagonal stripes, the words “sterile” or “autoclaved” when exposed to temperatures of 121°C.  Tape indicators are typically placed on the exterior of the waste load.  If the temperature sensitive tape does not indicate that a temperature of at least 121°C was reached during the sterilization process, the load is not considered decontaminated.   If tape indicators fail on two consecutive loads, notify your Department Safety Manager.

Tape indicators are not designed nor intended to prove that organisms have actually been killed. They indicate that a temperature of 121°C has been achieved within the autoclave.  EHS recommends that you DO NOT use autoclave tape as the only indicator of decontamination or sterilization.

Integrated Chemical Indicator Strips

Integrated chemical indicator strips provide a limited validation of temperature and time by displaying a color change after exposure to  normal autoclave operating temperatures of 121ºC for several minutes.  Chemical color change indicators can be placed within the waste load.  If the chemical indicators fail on two consecutive loads, notify your Department Safety Manager.                             

Biological Indicators

Biological indicator vials contain spores from B. stearothermophilus, a microorganism that is inactivated when exposed to 121.1oC saturated steam for a minimum of 20 minutes. Autoclaves used to treat biological waste will be evaluated with a biological indicator by EHS on a quarterly basis.


  • EHS will coordinate biological validation testing with laboratory staff.
  • The indicators will be incubated by EHS for 24 hours at 60°C with a control that has been maintained at room temperature.


  • If the autoclaved indicator exhibits growth, the validation has failed and will be repeated.
  • If the second validation indicator fails, EHS will notify the Department Safety Manager and request service on the autoclave.  Autoclave should not be used until service has been conducted and the validation test passes.
  • Validation tests results are emailed by EHS staff to the appropriate labs and the Department Safety Manager.
  • EHS maintains documentation of all validation tests.
Biological Indicator Test Results


Autoclave Log:

An autoclave log containing the following details should be maintained by lab staff:

  • Date, time, and operator’s name
  • Contact information: Laboratory, room number, phone number
  • Type of material sterilized/cycle
  • Temperature, pressure, and length of time the load is sterilized.

Biological Indicator Test Results

  • EHS maintains all biological indicator test results.


Meagan Fitzpatrick
Biosafety Officer

Halina Staniszewska
Sr. Lab Safety Specialist