If you’re working in a clinical, dental, or laboratory setting, sterilisation isn’t just a procedure — it’s non-negotiable. And at the centre of that process is your sterilising equipment. Among the wide range of available options, autoclaves come in different classes with specific capabilities, and one of the most common dilemmas for buyers and operators is choosing between Class B and Class S models.
Let’s explore what sets these two apart, how to make the right choice, and why this decision can affect compliance, efficiency and ultimately patient safety.
What Is a Class B Autoclave?
Class B autoclaves are the heavy hitters of bench-top sterilisation. Designed to meet the most rigorous standards, they’re capable of sterilising solid, hollow, porous and wrapped instruments. That makes them suitable for dental practices, surgical clinics and anywhere complex tools are used.
What sets them apart is their use of a pre-vacuum phase. This step removes air from the chamber before the steam cycle begins, allowing steam to reach every part of the instrument. Without it, pockets of air can create cold spots, leaving instruments improperly sterilised.
You’ll find Class B units where regulatory standards are highest, especially when reprocessing critical or semi-critical tools. If you’re working with loads that include items like wrapped scalers or hollow handpieces, you need that vacuum performance to ensure full penetration. If you’re wondering how to choose the best autoclave for dental clinics, a Class B unit is likely the top choice.
What Is a Class S Autoclave?
Class S autoclaves fall somewhere in the middle — they’re more advanced than basic Class N units but not quite as robust as Class B. These machines are typically used for unwrapped solid instruments or certain textiles, depending on the manufacturer’s guidelines.
Some Class S units do offer pre-vacuum cycles, but it’s not standard. Their performance is defined more by their specific configuration than by a universal standard. This makes them suitable for facilities with less demanding sterilisation needs or where fewer types of instruments are processed.
They’re often seen in beauty clinics, podiatry practices and veterinary surgeries where hollow or porous loads aren’t as common. When weighing up the different types and benefits of autoclaves, Class S models are a good middle-ground between affordability and functionality.
Key Performance Differences Between Class B and S
At a glance, the main differences between Class B and Class S units boil down to steam penetration, versatility and regulatory compliance. Class B autoclaves use a fractionated vacuum process, which means they perform multiple vacuum and steam pulses to remove air and ensure uniform sterilisation.
Class S autoclaves typically skip this step or perform a less intense version. This limits their ability to sterilise hollow or wrapped instruments effectively. They can still perform well in the right context but shouldn’t be used interchangeably.
Here’s a practical example: A dental clinic reprocessing wrapped surgical kits with hollow tubing needs the thoroughness of a Class B. A nail salon sterilising simple, unwrapped tools may find Class S sufficient. This distinction becomes clearer when you’re choosing the best autoclaves and sterilisers for your clinic. Understanding what you’re sterilising — and how often — is crucial.
Regulatory Standards and Compliance in Australia
In Australia, sterilisation practices are heavily regulated, particularly in medical and dental environments. Standards like AS/NZS 4815 and AS/NZS 4187 outline the requirements for infection control and sterilisation.
Class B autoclaves are explicitly designed to meet these standards. Their validated cycles and documentation features make them a common choice in accredited facilities. Class S units, while not necessarily non-compliant, require careful use within manufacturer specifications.
Auditors often ask for test records, cycle logs and proof of equipment suitability. If you’re running a Class S machine in a high-risk setting, you may need extra documentation to demonstrate its fitness for purpose.
Cost and Maintenance Considerations
One of the biggest reasons clinics lean toward Class S autoclaves is cost. On average, they’re more affordable up front and sometimes have lower maintenance needs. But that lower entry cost can come at the price of flexibility.
Class B models, while more expensive, reduce the need for multiple sterilisation units and can future-proof your operations as your instrument range grows. They also often include cycle logging, advanced sensors and remote diagnostics — all helpful for audit trails and troubleshooting.
When budgeting for equipment, consider not just the purchase price but the long-term service support and operational efficiency.
Energy Efficiency and Environmental Impact
It’s worth noting that modern autoclaves — particularly Class B units — are becoming more energy-efficient. Features like eco-cycles, improved insulation and intelligent drying phases are reducing water and power usage.
However, Class S models often have a smaller footprint, which can be beneficial in compact workspaces. Their simpler operation can also mean fewer moving parts and potentially less waste.
Still, if sustainability is a key driver, look into newer Class B models with energy-saving certifications and smart load detection.
Case Study: Dental Clinic Compliance Audit
A suburban dental clinic in Brisbane recently underwent an unannounced compliance audit by the local health authority. They had been using a Class S autoclave for several years, believing it met their needs. However, they were regularly sterilising wrapped hollow instruments.
The audit flagged the autoclave as unsuitable for this application. Despite passing chemical indicator tests, the lack of vacuum cycles meant the instruments could not be reliably sterilised. The clinic had to suspend services, invest in a compliant Class B unit, and retrain staff on correct cycle selection.
This case highlights the importance of matching your equipment’s capabilities to your clinical workload — not just for best practice, but to avoid costly downtime and reputational risk.
User Training and Ease of Operation
Class B autoclaves often come with more advanced settings and options, which can be overwhelming without proper training. However, many newer models have user-friendly touchscreens and programmable presets that simplify day-to-day use.
Class S units tend to have fewer buttons and fewer options — which can be a plus for teams with minimal technical knowledge or smaller operations.
Regardless of class, investing in good training is essential. Understanding cycle types, load configurations and daily maintenance helps reduce errors and keeps your autoclave running reliably.
FAQs
1) Do I need a Class B autoclave for a beauty salon?
Not necessarily. A Class S autoclave may be sufficient for a beauty salon, especially if you’re only sterilising solid, unwrapped instruments like tweezers or nail clippers. However, if your services expand to include more invasive procedures — such as dermal needling or treatments involving hollow instruments — you’ll need to upgrade to a Class B model to ensure complete sterilisation. Always check with your local regulations and infection control guidelines to make sure you’re meeting compliance requirements for your industry.
2) Can Class S autoclaves sterilise wrapped instruments?
Some Class S autoclaves are capable of sterilising wrapped instruments, but this depends heavily on the specific model and its features. Many do not have the vacuum phases necessary to penetrate wrapped or porous loads thoroughly. If you’re regularly processing wrapped kits or need to ensure sterility for high-risk procedures, it’s best to invest in a Class B unit. Using a Class S autoclave beyond its design can compromise sterilisation quality and lead to compliance issues during audits.
3) How often should autoclaves be serviced?
Autoclaves should undergo professional servicing at least once a year, but this can vary depending on usage frequency and manufacturer recommendations. Daily and weekly maintenance tasks — like cleaning the chamber and checking gaskets — should be part of your regular routine. Keeping detailed service logs helps maintain compliance and ensures your autoclave performs at its best. For Class B units especially, service intervals may include software checks, cycle validation and filter replacements.
4) Are Class B autoclaves harder to use?
Class B autoclaves can appear more complex because they offer multiple cycle types, programmable options and integrated documentation features. However, many newer models are designed with intuitive touchscreens and user presets that simplify operation. Once your staff is trained, daily use becomes second nature. The additional control and data tracking features make Class B autoclaves ideal for settings where traceability and detailed compliance records are required.
5) What’s the best autoclave for a multi-practitioner clinic?
A Class B autoclave is generally the best choice for a busy, multi-practitioner clinic. It offers the flexibility to handle a wide range of instruments, including hollow, wrapped and porous loads. This means you won’t need multiple machines or complex scheduling just to get everything sterilised. Plus, features like load traceability, barcode scanning and eco-cycles can boost efficiency. While the upfront cost is higher, the long-term return on reliability and compliance often makes it worthwhile.
Choose with Confidence at MES Australia
The right autoclave doesn’t just tick a box — it underpins the safety and success of your operations. Whether you run a boutique salon or a bustling dental practice, choosing between Class B and Class S autoclaves comes down to what you’re sterilising, how often and under what regulations.
Think ahead, ask the right questions and don’t let short-term cost-cutting compromise long-term outcomes. When in doubt, our expert team at MES Australia is here to help you navigate the options and future-proof your practice.
For all your autoclave requirements, please call us today on 1300 342 013 or leave an enquiry.
