Autoclave machine: Principle, How to Use and Maintenance

An autoclave is a specialized machine used in laboratories, hospitals, and other healthcare settings to sterilize equipment and materials through the use of high-pressure steam for a specific duration. This process is known as steam sterilization and involves exposing materials to steam at high temperatures for a specific period of time aiming to kill all microorganisms inside the machine. Autoclaves are essential in maintaining aseptic techniques and reducing the risk of contamination and are important in healthcare, research, and the food processing industry. In this article, we will cover the autoclave principles, proper use, and maintenance.

The principles of autoclaves

Autoclaves use high-pressure steam to kill microorganisms, including bacteria, viruses, and fungi, through the process of steam sterilization. The temperature, pressure, and sterilization time are carefully controlled to ensure that materials are properly sterilized. To be effectively eliminating the microbes, the autoclave usually operates at 121ᵒC / 15psi for 20 minutes as most of the bacteria cannot withstand this condition.

Proper use of autoclaves

Before any sterilization process takes place, ensure the inside chamber is clean and the water inside the autoclave is sufficient for the process. To use an autoclave, materials must be placed in the sterilization chamber and exposed to steam at high temperatures and pressures. Never put materials that cannot be autoclaved, for instance, flammable materials, radioactive materials, and plastics that are not intended for sterilization. It is important to properly arrange and secure materials in the chamber by using an autoclave basket to ensure that they are evenly exposed to the steam. Make sure that all bottle caps are not tightly closed to allow steam air to enter the bottle during the process. After sterilization, materials must be allowed to cool to room temperature before being removed from the autoclave. Read more on how to properly use an autoclave.

Cleaning and maintaining autoclaves

Regular cleaning and maintenance of autoclaves are crucial in ensuring proper operation. This includes cleaning the sterilization chamber and other parts of the machine, such as the door gasket and drain lines, changing the water, and checking and replacing any worn or damaged parts. Regular cleaning and maintenance can effectively secure your sterilization and ensure prolong use of the equipment.

Furthermore, in clinical applications, the autoclave may be used to sterilize material or decontaminate biological waste, it is a must to regularly do a proper cleaning routine such as changing the water on daily basis, run a weekly empty sterilization and cleaning the internal chamber to prevent any cross contamination.


Achieving secure sterilization

To ensure that materials are properly sterilized, it is necessary to follow proper autoclave protocol, including using the correct sterilization temperature and time for the specific materials being sterilized and properly loading and securing materials in the sterilization chamber. It is also important to regularly calibrate the autoclave to ensure that it is operating at the correct temperatures and pressures. Tomy Autoclave comes internal sensor and printer that allow the user to prevent and monitor heat transfer lag times of the autoclave. Heat transfer time lag is the time difference between the autoclave chamber temperature and the temperature of the articles to be sterilized. During a sterilization process, the sterilization temperature of the articles arrives later than the displayed or chamber temperature, causing the articles not to be appropriately and sufficiently sterilized at the temperature of 121ᵒC. Read more about how to achieve secure sterilization.

Autoclaving hazardous biological materials

When working with hazardous biological materials, it is essential to follow proper autoclave protocol to ensure the safety of the operator and the laboratory environment.

Guidelines on autoclaving biological hazards.

  1. wear proper personal protective equipment (PPE).

  2. All biological hazards need to be soaked with disinfectant (70% of alcohol or 0.1% sodium hypochlorite) for 30 minutes before the autoclaving process.

  3. drain all disinfectants before the autoclaving process. Autoclave at 121ᵒC for 30 minutes.

  4. Drain out the water daily and use the ratio of 1 part tap water and 9 parts of distilled water according to the manufacturer’s manual.

  5. it is advisable to empty run the autoclave at 121ᵒC for 30 minutes after autoclaving biological waste to ensure proper basket and chamber sterilization.

Validating autoclaves with biological indicators

To verify that an autoclave is effectively sterilizing materials, it is necessary to use a biological indicator. A biological indicator contains a specially formulated culture medium and microorganism, G. stearothermophilus spores that are known to be resistant to sterilization and are used to test the autoclave's performance. By exposing the biological indicator to the sterilization process and then culturing it to see if it has survived, the effectiveness of the autoclave can be determined. If the biological indicator does not survive, it indicates that the autoclave is operating correctly.

Learn more about Biological Indicator.


In summary, autoclaves are crucial tools in any laboratory or healthcare setting that requires the sterilization of materials. By understanding their principle, proper use, and maintenance, you can ensure that autoclaves are effective and reliable tools for maintaining aseptic techniques and reducing the risk of contamination.

We look forward to serving your needs, including autoclave accessories and services.

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