Autoclave classes ranked: differences between N, S, and B-type sterilizers


When it comes to autoclave classes (AKA steam sterilizers),three major types—N, S, and B—stand out. Each sterilizer comes with its unique features and applications. In Celitron’s next article, we will provide you with a comprehensive guide that compares these autoclave classes, ranking them based on their differences and highlighting their significance in various settings.

As a professional autoclave manufacturer in Europe, we’re here to help you make a more informed choice about which steam sterilizer better suits the needs of your medical facility. Let’s get started!

How autoclave sterilizers work, regardless of class and type

Let’s begin with the basics and clarify why you need to consider autoclave classes before making your choice.

In the healthcare industry, autoclaves play a crucial role in maintaining safety and hygiene standards. These machines resemble pressure cookers and provide an ideal solution to sterilize certain types of medical waste and tools/equipment.

This allows medical facilities to:

  • Treat medical waste onsite (such as items contaminated by blood) and then dispose of it like regular municipal waste, since it will be free from infectious foreign materials.
  • Furthermore, staff can sterilize medical tools like surgical instruments or certain elements of PPE (personal protective equipment),which can then be reused again for the treatment of patients. This is a great help in reducing the amount of waste generated at medical facilities and preventing HAIs (Healthcare-Associated Infections).

Regardless of autoclave class and type, all sterilizers operate using high-temperature, saturated steam under pressure, usually between 1.1 and 2.1. bar. The temperature can range between 121 and 134 degrees Celsius and helps eliminate even heat-resistant bacteria.

Comparing and ranking autoclave types: N, S, and B classes

Now that you know the basics about how autoclaves work, let’s see how classes such as N-type, S-type, and B-type sterilizers affect their operation and efficacity.

All sterilizer types use steam, but their class affects HOW the steam is introduced inside the autoclave’s capacity chamber. The reason why this matters is because it not only affects the speed of the steam sterilization process but also what types of items can be treated by that specific class of autoclave.

In a nutshell: versatility and speed become crucial factors affected by autoclave classes.

There are also other factors you should consider when considering a certain type of sterilizer, such as:

  • The capacity chamber of the autoclave and the available space at your facility.
  • Record-keeping and digital outputs to facilitate documentation.
  • Maintenance requirements.
  • Capital and operations costs.
  • Manual or automatic operation.

N-type autoclave sterilizer – Basic class, ranked 3rd place

Autoclaves with the type-N designation represent the earliest, and therefore most “basic” class designs in the healthcare industry. This means that by now, they can be considered to be a bit outdated compared to their modern versions – however, it doesn’t mean it’s automatically a bad choice.

The “N” in N-type autoclaves stands for “naked solid products”. As such, this sterilizer class can only be used to treat flat, unwrapped, solid medical tools. NO hollow or textile items, porous loads, or wrapped medical items in pouches, which greatly hurts their versatility. There, we cannot recommend these for facilities like large hospitals, which certainly need to treat more types of loads in their day-to-day activities.

Class N autoclaves cannot guarantee full steam penetration because of the way steam is introduced inside their chamber. These sterilizers use a process called gravity displacement, which gradually pushes the air out of the autoclave’s chamber. Air is one of the greatest obstacles for efficient sterilization, and without the vacuum pump used by more advanced models, this process is slower, but also cannot remove 100% of the air inside.

This also affects the drying process (or lack of a proper one),as instruments may still come out wet from the autoclave.

Despite all this, these sterilizers can still be a great choice for facilities that don’t need to treat that many types of medical items, and are looking for the cheapest autoclaves available on the market. If you primarily deal with non-packaged solid instruments, type N may suffice.

S-type autoclave sterilizer – Intermediate class, ranked 2nd place

As an intermediate class, the S-type sterilizers refer to a much broader range of autoclaves sold on the healthcare market, with varying features. This is why it’s much more difficult to provide a general description for this category, and should pay even more attention to the manufacturer’s instructions about technical specs and compatible materials.

Still, in most cases, you can expect more control and precision in temperature and pressure settings, as well as more customizability compared to the base N-type autoclaves.

You can also expect more versatility compared to N-type models, but S-type autoclaves still may not treat all materials that class B machines can.

S-type autoclaves can also have their own drying mechanism, and even a vacuum pump, though it is not an overly common feature, and most models still use gravity displacement to displace the air from their chamber.

B-type autoclave sterilizer – Advanced class, ranked 1st place

Finally, the clear winner of this ranking of autoclave classes is the B-type sterilizer. Only the most advanced models can earn this categorization.

The distinct identifier of autoclaves with this designation is the obligatory presence of a vacuum pump. This helps them completely remove the air from their chamber. This not only speeds up the whole process (since you don’t have to wait until the air is pushed out via gravity displacement) but also ensures much more efficient sterilization. With the greatest obstacle (air) out of the picture, steam can penetrate every single part of the load inside.

The result? Unparalleled versatility and speed: Celitron’s B-type autoclaves can complete the sterilization process in about 20 minutes. Including the drying and cooling phases.

Of course, the exact time of the process will always be affected by the type of load and the number of items inside, but you can still expect quicker cycles on average.

All in all, autoclaves with the type-B designation are the go-to option for any medical facility or lab that deals with intricate and hollow instruments, and needs the most versatile option to sterilize the wide range of materials and equipment they use.

The benefits of using Celitron’s type-B autoclave sterilizers

  • Capacities for facilities of all sizes. We provide options for small clinics with limited available space and large hospitals alike. All of our autoclaves have the type-B designation, regardless of size.
  • Easy external documentation via PC connection.
  • Self and remote diagnosis for easy maintenance. You can also count on Celitron’s after-sales support.
  • Low operational costs. Thanks to advanced water and energy-saving systems. This also contributes to reducing your environmental footprint.
  • Fully automated operation. Easy to learn, easy to use, with automatic safety features.

As you can see, there are many benefits to using autoclaves with type-B designations. These sterilizers provide a fast and versatile onsite solution for medical facilities of all sizes.

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