Vacuum Heat Treatment for 3D Printing: The Ultimate Guide
by aifurnaces
Jul 4, 2022

How to Do Dry Heat Sterilization Using a Lab Oven

Drying, baking, and sintering are some of the functions of a lab drying oven. On top of these heat treatment processes, you can also utilize lab ovens for sterilizing, specifically dry heat sterilization.

In this sterilization method, you’ll place the object inside an oven and heat it at 150 to 170°C  for 60 to 150 minutes. This temperature range ensures that no moisture will remain in the object after heating. 

Since this process takes place in an enclosed environment with no air circulation, there is no chance of contamination by microorganisms or particles from outside sources while you’re heating your items to the maximum temperature.

What is Dry Heat Sterilization?

Dry heat sterilization is a method for killing microorganisms in materials sensitive to moisture or chemical agents. It uses hot air that is either free from water vapor or has very little of it. It also doesn’t use any additive sanitizing agents or chemicals.

This method is ideal for all kinds of metals and powders that cannot be compromised by moisture and chemical agents, such as anhydrous oils, fats, and glassware. Additionally, it is great for paper-wrapped items and medical instruments, especially surgical tools. The heat penetrates through the wrapping to sanitize the inside.

Advantages of Dry Heat Sterilization

Here are other benefits you can experience by leveraging dry heat sterilization in your lab.

  1. The cost of operation and heating cycles is generally low

Operation and heating cycle costs are low because dry heat sterilization uses simple equipment. The energy required is relatively low compared with other methods since the process is similar to oven drying. In short, it has minimal utility costs. 

  1. Metals that can handle heat can be sterilized quickly

Dry heat sterilization works with metallic items that can take heat well. It kills bacteria at a temperature high enough to kill them but not too high that it damages the metal.

  1. Dry heat is non-corrosive for metallic materials

This sterilization method does not corrode metals at low temperatures, unlike steam sterilization. Dry heat has little to no moisture, meaning there will be no water vapor interfering with a metal’s chemical structure. This is because water vaporizes at 100°C, which is lower than most sterilization temperatures. 

  1. The process involves no toxic agents

There is always the concern that lab equipment and methods will cause toxic fumes, corrosion, and pollution. Dry heat sterilization doesn’t produce these negative effects, making the process safer while keeping costs low and leaving no harmful substances in the environment.

  1. Dry heat sterilization doesn’t require human attendance during the operation

A major advantage to this sterilization method is its ability to operate on its own. You only have to set the oven and leave it to complete the cycle. You can also automate this process, depending on your lab oven. This reduces your staff’s workload and allows them to focus on other complex tasks.

2 Types of Dry Heat Sterilization

There are two ways to do dry heat sterilization. You can use either, depending on your requirements.

  1. Static-air sterilization

The chamber of a static-air oven is heated with dry heat, and the air circulates via gravity convection. This means that the hot air naturally rises and expands, then falls as it loses heat energy. 

Static-air sterilization is recommended for small batches of material that can be placed on racks inside the chamber. One thing to keep in mind is that this process can take a little longer because it only relies on natural convection to reach the desired temperature. 

Additionally, note that if the temperature is inaccurate or there’s too much moisture in the air, it can damage or spoil the product. This process is a lot slower than forced-air sterilization, but it’s a good, low-cost option if you’re not facing time constraints.  

  1. Forced-air sterilization

This method works under the principle of conduction. Forced air drying ovens use a fan to move the hot air around. This prevents the hot air from rising to the top while keeping the cooler air on the bottom.

An advantage to using this method is that it circulates the hot air consistently, maintaining the ideal temperature in the oven. The constant movement of the hot air also allows you to dry and sterilize objects faster.

If you need a quicker sterilization process, especially if it involves medical instruments, forced-air sterilization is the way to go. It can quickly kill bacteria, viruses, and other microorganisms that can harm laboratories and healthcare facilities. 

High-Quality Lab Ovens for Sterilization

Sterilization is an integral process in decontamination, and dry heat sterilization is one of the most cost-effective methods. It can sterilize even moisture-sensitive materials while keeping operating expenses low.

If you are looking for a lab oven to perform dry heat sterilization, check out AI Furnaces’ forced air drying ovens. Our forced air ovens can reach up to 250°C, ideal for dry heat sterilization and other high-temperature heat treatment processes. 

We also carry other types of lab ovens and furnaces for different lab processes. You can browse our selection here. If you need assistance in selecting the right equipment for your lab, fill out the contact form and we’ll get in touch with you. 


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