Autoclave operators who steam sterilize biohazardous waste must operate autoclaves as specified by the Seattle-King County Health Department according to the Seattle Municipal Code, Section 21.43.050. Autoclave operation and monitoring requirements are as follows:

Broken Autoclaves

If an autoclave is not working properly, discontinue use immediately. Post a sign alerting others not to use the autoclave and notify the PI or Lab Manager to arrange for repair.

Disposal Of Spores

Live incubated or other live biological spores should be autoclaved again before disposal or incinerated. Please refer to Biohazardous Waste for additional disposal information.


Operators must ensure that each autoclave is routinely monitored as follows:

  • Temperature Monitoring - Operators must check and document recording and/or indicating thermometers during each complete cycle to ensure the attainment of a minimum temperature of two hundred fifty degrees Fahrenheit (250ºF) or (121ºC) for at least one-half (1/2) hour or longer, depending on quantity and compaction of the load, in order to achieve sterilization of the entire load. Note: Greater time and / or temperatures may be necessary to effectively sterilize a load.
    • Thermometer Calibration - Thermometers must be checked for calibration at least annually.

  • Heat Sensitive Tape Monitoring - Operators must use heat-sensitive tape or other device for each load that is processed to indicate the load has undergone the steam sterilization process. Remember this tape only indicates that the proper temperature has been reached, but does not indicate it was heated for the proper time.

  • Chemical Integrator Monitoring - Operators must use Thermalog-S. Thermalog-S is the ONLY chemical integrator currently approved by the Seattle-King County Health Department. Place the chemical integrator in the center of each load to confirm attainment of adequate sterilization conditions. Attach a string to thermal integrator for easy retrieval after the autoclave cycle is complete.

  • Biological Indicator Monitoring - Operators must use the biological indicator Bacillus stearothermophilus placed at the center of a load processed under standard operating conditions at least monthly to confirm the attainment of adequate sterilization conditions. Following is the biological indicator monitoring test procedures outlined in Section IV, G, 7 of the Biosafety Manual:
    1. Use spore ampules or strips with an average population of 104 to 106 organisms adjusted to the following resistance data - survives steam heat at 250º F for five minutes and is killed at 250º F in thirteen minutes.
    2. The most reliable means for determining whether a sterilizing cycle has been successful is by planting biological indicators throughout the load before the load is subjected to the sterilization process.
    3. Operate the autoclave in accordance with manufacturer's instruction. The cycle (time and temperature) shall be the minimum as required by user's lab procedures.
    4. Record chamber temperature as shown by the sterilizer indicator autoclave's thermometer.
    5. Upon completion of cycle, fast exhaust the chamber and remove test spore strips from the autoclave.
    6. Incubate the Bacillus stearothermophilus test strips according to manufacturer's instructions.
    7. Record results on the Quality Control Checklist.
    8. The completed Quality Control Checklist must be retained by the lab for six years.

  • Structural Inspection - Autoclaves are considered to be unfired pressure vessels. They must be inspected every two years by a qualified inspector as per WAC 296-104-100. Contact Facilities Services Maintenance & Alterations for more information regarding scheduling an Autoclave Structural Inspection.


Operators must maintain records and procedures specified for temperature monitoring, chemical integrator monitoring, and biological indicator monitoring in the lab for a period of not less than one (1) year. The Quality Control Checklist must be retained in the lab for six years.


It is the responsibility of each lab to ensure that training, recordkeeping, and testing is conducted for each autoclave in their lab. Recordkeeping is best maintained by the individual users of the autoclave. Designate a "contact" who must:

  1. Test and assure proper operation of the unit
  2. Notify EH&S when an autoclave is removed or installed
  3. Notify users when an autoclave is not functioning properly

Report the contact's name to EH&S on the Quality Control Checklist, and post it near the autoclave.

Standard Operating Procedure

Operators are required to prepare written Standard Operating Procedures for each steam sterilizer for which they are responsible. The plan must address each of the following:

  • Time
  • Temperature
  • Pressure
  • Type of waste
  • Type of container(s)
  • Closure on container(s)
  • Pattern of loading
  • Water content
  • Maximum load quantity


An autoclave training program must be developed and implemented. All users must be trained before operating an autoclave and written operating procedures must be readily accessible.