The Importance Of Autoclave Calibration And Validation

April 01, 2022

An autoclave is one of the most powerful pieces of equipment in a laboratory setting, drawing on pressure and heat to rapidly sterilize critical equipment more quickly and effectively than nearly any other method. An Autoclave uses steam under pressure to kill harmful bacteria, viruses, fungi, and spores on items that are placed inside. Sterilization with an autoclave is necessary to keep equipment contaminant-free after usage, protecting the integrity of the work done in the lab as well as the safety of personnel and end users.

Autoclave maintenance is thus critically important to ensure that the autoclave is operating as intended and is fulfilling its required purposes. Autoclave calibration and autoclave validation are two of the most important ways to verify your autoclave is working to spec.

Validation and Calibration of Autoclave Equipment: What’s the Difference?

First, we will explain the difference between the two, and then we will look at a sample autoclave calibration procedure and an autoclave validation procedure.

Autoclave Calibration

Autoclave calibration is the process of assuring the autoclave is meeting the temperature and pressure for which it is set, using calibrated equipment that is known to be accurate, such as an NIST-traceable temperature and pressure probe. Autoclave calibration can occur for a single temperature point, or for multiple points, depending on the application at hand.

Autoclave Validation

Autoclave validation is performed to verify the autoclave has been installed, operates and performs in accordance with applicable specifications. Temperature and pressure distribution studies are performed in the empty chamber (Operational Qualification) as well as in a chamber loaded with materials (Performance Qualification). These studies can be performed for multiple cycles with multiple load configurations, if desired, to assure the autoclave is performing to stated specifications.

How to Calibrate Autoclave Equipment

The following steps provide an overview of the autoclave calibration process:

  • Benchmark the zero and gain measurements for each sensor in the autoclave.
  • Fully shut down the autoclave, waiting for the steam to completely dissipate and the pressure to reach zero.
  • Place the autoclave sensors as close to the calibration equipment as possible.
  • Set the autoclave to the desired temperature and pressure, and wait at least one minute to reduce variation in the reading. Record the standard and transducer data.
  • Run a linear regression of the data using a program such as Excel, then enter the established zero and gain values into the autoclave controller to calibrate.
  • Verify the calibration with another cycle.
  • How to Validate Autoclave Equipment
  • The autoclave equipment validation process includes multiple steps to confirm the unit is installed, operating, and performing in accordance with applicable specifications.

Steps in this process include:

  • Installation Qualification (IQ) – An inspection will be conducted by physically inspecting the unit and any associated equipment. An inspection of the utilities supplied to the unit will be performed and verified to be in conformance with requirements.
  • Operational Qualification (OQ) – An empty chamber temperature and pressure mapping study will be performed for one cycle. A functional verification of unit controls will also be performed as part of the OQ.
  • Performance Qualification (PQ) – The chamber will be loaded with materials provided by the customer. Then, temperature and pressure mapping studies will be performed for the required number of cycles and load configurations. For the PQ, TSS recommends (3) cycles per load configuration. For all PQ studies, biological indicators will be placed in the chamber to quantify biocidal efficacy.

Autoclave equipment must be kept up to date and well-maintained to keep equipment sterile and safe for critical processes throughout the laboratory. Technical Safety Services offers autoclave calibration services and validation services. We also provide numerous other services devoted to keeping lab facilities operating safely and efficiently — including testing for all lab equipment, certification, commissioning, and decommissioning, etc.

To learn more, contact us today.

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