Sterilisation only works when the right temperature is reached everywhere in the load, for long enough. Built-in chamber sensors tell you what happened at one point near the chamber wall — independent sterilizer temperature monitoring with data loggers tells you what happened inside the load itself.
Steam sterilizers (autoclaves)
Steam sterilisers are the most common type in hospitals, laboratories and pharmaceutical plants. Typical cycles hold at 121 °C or 134 °C, with saturated steam under pressure.
What to monitor:
- Temperature across the chamber (heat distribution)
- Temperature inside the load (heat penetration)
- Chamber pressure, to confirm saturated steam
Suitable loggers: the submersible HiTemp140, or the complete AVS140-6 autoclave validation set with five temperature loggers and a pressure logger.
Dry heat sterilizers
Dry heat ovens sterilise glassware, metal instruments and heat-stable materials using hot air rather than steam. They run much hotter than steam cycles — commonly 160 °C to 180 °C, and higher for depyrogenation — which is beyond the rating of standard high temperature loggers.
The solution is a thermal barrier. In the MadgeTech DHS dry heat sterilization system, a HiTemp140-M12 logger sits inside the ThermoVault Max thermal barrier while a 36-inch RTD probe measures the chamber or load. The barrier keeps the electronics cool for the duration of the cycle.
Routine monitoring vs validation
| | Routine monitoring | Validation / requalification | |---|---|---| | Purpose | Confirm each cycle ran correctly | Prove the process is capable and consistent | | Frequency | Every cycle or batch | Installation, after changes, then periodically | | Loggers | One or a few | Many, across the chamber and load | | Output | Cycle record | Protocol, data, analysis and report |
Records auditors expect
- Logger serial numbers and valid calibration certificates
- Logger positions for each run
- Raw data plus a clear summary: hold time, minimum and maximum temperatures, and F0 where relevant
- For electronic records, secure software with audit trails — MadgeTech Secure software supports 21 CFR Part 11
Keep your loggers themselves in check with regular calibration.
This guide is part of our
Autoclave Validation
