Mastering Sterilization: The Essential Guide to Choosing the Right Class of Autoclave

Autoclaves play an indispensable role in ensuring the sterility of equipment and materials across various industries, most notably in healthcare, pharmaceuticals, and scientific research. These powerful machines use steam under high pressure to kill bacteria, viruses, fungi, and spores, making them a critical component in the fight against infections and contamination.

Given the range of applications and requirements for sterilization, autoclaves are classified into different categories, each designed to meet specific standards of sterilization efficacy.

This blog post delves into the different classes of autoclaves—Class N, Class S, and Class B—highlighting their unique features, applications, and how to choose the right one for your needs. By understanding the distinctions between these classes, users can make informed decisions that ensure safety, efficiency, and compliance with industry standards.

What is an Autoclave? 

An autoclave is a sophisticated device designed to perform sterilization by applying steam under high pressure at temperatures well above boiling point. The concept of using steam to sterilize instruments dates back to the 19th century, revolutionizing medical practices by drastically reducing infection rates.

Modern autoclaves come in various sizes and are more technologically advanced, but the underlying principle remains the same: to achieve sterilization by exposing materials to high-temperature steam for a specific period. This process effectively destroys all forms of microbial life, including highly resistant spores, ensuring that surgical instruments, laboratory equipment, and other materials are free from contaminants and safe for use.

The Importance of Sterilization 

Sterilization is a critical process in many fields, particularly in healthcare, where it is essential for preventing infections and ensuring patient safety. Autoclaves serve as the backbone of sterilization protocols, offering a reliable method for rendering instruments and materials sterile. In scientific research, sterilization prevents contamination of experiments, maintaining the integrity of results. In the tattoo and beauty industries, autoclaves protect customers from the transmission of infectious diseases.

The effectiveness of autoclaves in achieving sterilization lies in their ability to penetrate materials with high-temperature steam, ensuring that even the most durable microbial spores are eradicated. This level of sterilization cannot be achieved through other methods such as dry heat or chemical disinfectants, making autoclaves indispensable in settings where sterility is paramount.

Overview of Autoclave Classes

Before delving into specific uses in nail salons and tattoo shops, it's crucial to understand the classification of autoclaves. Autoclaves are categorized into three main classes—N, S, and B—based on their sterilization capabilities and the types of loads they can handle. Class N autoclaves are designed for solid, un-wrapped items and are generally considered basic. Class S autoclaves offer more flexibility, capable of sterilizing wrapped goods and some types of hollow instruments.

Class B autoclaves are the most advanced, suitable for a wide range of instruments, including wrapped, unwrapped, solid, and hollow items, making them ideal for settings requiring the highest sterilization standards. This classification system ensures that various industries can select an autoclave that best fits their specific sterilization requirements.

Autoclaves in Nail Salons and Tattoo Shops 

Nail salons and tattoo shops are environments where the risk of cross-contamination and infection is significant. Given the intimate contact with customers' skin and the potential exposure to bloodborne pathogens, strict sterilization protocols are essential. Autoclaves play a vital role in these settings, providing a reliable method for sterilizing equipment that cannot be achieved through conventional cleaning methods.

Nail Salons

In nail salons, tools such as clippers, cuticle pushers, and nail drills come into direct contact with the skin and can harbor bacteria and fungi if not properly sterilized. Using a Class B autoclave, the most comprehensive of the classes, ensures that these tools are sterile and safe for use on clients. The high-pressure steam effectively penetrates every surface of the tools, eliminating all microbial life. This level of sterilization reassures clients that their health and safety are taken seriously, enhancing the salon's reputation and trustworthiness.

Tattoo Shops

Tattooing involves piercing the skin, posing a higher risk of infection transmission. The use of needles and other equipment that comes into direct contact with the client's bloodstream necessitates the highest sterilization standards.

Class B autoclaves are again the preferred choice for tattoo shops because of their ability to sterilize a variety of instruments, including those with complex designs and hollow parts. Ensuring that every needle, tube, and grip is thoroughly sterilized before use is critical in preventing the transmission of diseases such as hepatitis and HIV, thereby protecting both the client and the artist.

Choosing the Right Autoclave

For both nail salons and tattoo shops, selecting a Class B autoclave is advisable due to its versatility and superior sterilization capabilities. These establishments should consider factors such as the autoclave's capacity, cycle time, and ease of use when making a selection. Investing in a high-quality autoclave not only meets health regulations but also demonstrates a commitment to client safety and service excellence.

Maintenance and Training: Proper maintenance and regular servicing of the autoclave are crucial to ensure it operates efficiently and continues to meet sterilization standards.

Additionally, staff in nail salons and tattoo shops should receive thorough training on the correct operation of the autoclave, understanding the importance of sterilization, and how to properly prepare instruments for autoclaving. This comprehensive approach to sterilization safeguards against infections, ensuring a safe environment for both clients and employees.

Class N Autoclaves 

Class N autoclaves, also known as "Naked" autoclaves, are designed for sterilizing solid, un-wrapped items without hollow spaces. These autoclaves are most suited for tools and instruments that are simple in design and do not require complex sterilization processes.

The "N" in Class N stands for "Naked," indicating that these autoclaves are not intended for wrapped items or instruments with internal channels.

Ideal Uses: Class N autoclaves are commonly used in settings where the instruments to be sterilized do not have intricate designs or internal hollows, such as some dental practices, tattoo parlors for simple tools, and beauty salons for metal instruments. They are effective for solid items like scissors, forceps, and other non-complex tools.

Limitations: The primary limitation of Class N autoclaves is their inability to sterilize wrapped items or instruments with hollow sections effectively. This means they cannot ensure sterilization of items that require protection from recontamination after the sterilization process or instruments with internal channels where steam penetration might be insufficient.

Class S Autoclaves 

Class S autoclaves are a step up from Class N, designed to offer more flexibility in sterilization capabilities. They can sterilize wrapped goods and some hollow instruments, making them suitable for a broader range of applications. The "S" in Class S stands for "Special," indicating these autoclaves are designed for special types of loads that do not fit the criteria of Class N or B.

Ideal Uses: Class S autoclaves are versatile, making them ideal for clinics, dental offices, and laboratories that deal with both solid and some types of hollow instruments. They can handle various loads, including some wrapped instruments and textiles, providing a higher level of sterilization security than Class N autoclaves.

Limitations: While Class S autoclaves are more versatile than Class N, they still cannot accommodate all types of loads. They are not suitable for complex surgical instruments with long, narrow lumens or highly porous materials. Users must carefully select the type of loads based on the autoclave's specifications to ensure effective sterilization.

Class B Autoclaves

Class B autoclaves represent the highest standard in autoclave design, capable of sterilizing all types of loads, including wrapped and unwrapped items, solid and hollow instruments, and porous materials. The "B" stands for "Big/small," indicating their capacity to handle a wide range of instrument types and sizes, from small dental instruments to larger surgical tools.

Ideal Uses: Class B autoclaves are essential in hospitals, dental clinics with advanced surgical tools, and laboratories requiring the highest sterilization standards. They are particularly valuable in settings where the risk of infection is high and a wide variety of instruments and materials need sterilization.

Limitations: The primary limitation of Class B autoclaves is their cost. They are significantly more expensive than Class N and S autoclaves, reflecting their advanced capabilities. Additionally, their operation and maintenance might require more specialized knowledge, making them a more significant investment in terms of both money and training.

Choosing the Right Autoclave Class for Your Needs

Selecting the right class of autoclave depends on several factors, including the types of instruments to be sterilized, the volume of items, and specific industry standards. For nail salons and tattoo shops focusing on simple tools, a Class N autoclave might suffice. However, for medical and dental clinics dealing with a variety of instruments, including those with hollow spaces or requiring wrapping, a Class B autoclave would be the most appropriate choice.

Maintenance and Safety Considerations 

Regardless of the class, regular maintenance is crucial for all autoclaves to ensure their efficient operation and longevity.

This includes periodic servicing, cleaning, and validation tests to confirm sterilization effectiveness. Safety measures, such as wearing protective equipment and following manufacturer guidelines for operation, are essential to prevent accidents and ensure the autoclave's safe use.


Understanding the different classes of autoclaves and selecting the appropriate one for your needs is crucial for ensuring effective sterilization.

By considering the specific requirements of your industry and the types of instruments you need to sterilize, you can choose an autoclave that offers the best balance of functionality, safety, and cost-effectiveness. Remember, investing in the right autoclave not only ensures compliance with health and safety standards but also reflects a commitment to providing safe and reliable services.