Autoclave: what is it and what is it used for? All you need to know about the device

Thanks to technological progress, we can avoid life-threatening and health-threatening infections in places where they can occur, even if we are not aware of them. It is possible – among others – thanks to autoclaves. What are they, how do we classify them and where to place them?

Autoclave – what is it and how does it work?

Autoclave is a device designed for sterilization of various tools – cosmetic, surgical, dental, equipment used in aesthetic medicine parlors, piercing salons and tattoo studios. Moreover, thanks to the development of technology, autoclaves are now much smaller than they used to be, while at the same time they continue to increase their capabilities – for example they are faster and easier to use. What is more, the price of such devices is decreasing, making them more and more available and affordable. They are an essential part of the equipment of any of the abovementioned parlors, as effective sterilization is the basis for the hygienic and safe functioning of such parlor. The autoclave is a kind of hermetically sealed, heated tank used for chemical processes. Thanks to the thick walls inside its chamber, high pressure can be maintained, and it’s crucial for applying a higher temperature, which ensures more effective sterilization. In addition, the condensation of water vapor leads to the release of energy, which completely eliminates harmful microorganisms. The autoclave, thanks to its structure, allows the sterilization process to be carried out by using high pressure and steam, which kill microorganisms, including dangerous viruses and bacteria and all their spore forms. The use of steam-pressure autoclave is one of the most effective methods of sterilization. Sterilization by definition is the process of destroying all living forms of microorganisms, including spore forms. It can be done physically, chemically or mechanically. An instrument that is sterile – i.e. after a sterilization process – is completely safe for the human body. For sterilization to be effective, the material must be properly prepared, the process itself must be carried out correctly and the instruments have to be stored properly after sterilization. The equipment should first be pre-disinfected just after usage, washed under running water or using automatic washing machines, dried and then put into labelled packages to sterilize them. Correct sterilization should not damage or alter the equipment’s properties. The history of the autoclave dates back to 1679. The autoclave with a valve (safety flap), which was also a prototype of a steam boiler, was invented by a physicist of French origin – Denis Papin. In those days it was called “Papin's boiler”. It was also used as a pressure cooker. His invention was first demonstrated in 1682, during feast organized for members of the Royal Society in London. Thanks to Papin’s invention cooked dishes could be consumed during that celebration. Since then many changes in the production and use of autoclaves have occurred. Most of the processes have been automatized, the equipment is electronically controlled, supplied with distilled water or connected to the water supply system, and the processes are electronically archived. Some devices also have printer functions and displays showing the machine's operating stages. 

Autoclave classes – how do we divide them?

There are several classes of autoclaves available on the market. The classification is based on their intended use – according to instruments and products that can be sterilized inside. Categorization of autoclaves is defined by the European standard EN 13060 from 2004, which distinguishes three basic sterilization classes. This division includes only steam and vacuum sterilizers.

Class N autoclave

This is the lowest class of sterilizers. The Class N autoclave is a device used to sterilize simple materials such as solid, unpackaged batches. Due to the absence of a vacuum pump in this autoclave, it is not possible to sterilize hollow or porous batches or packaged instruments because the functions performed during the cycle do not physically meet the requirements of the relevant tests. This means, that the device is unsafe to sterilize the abovementioned batches. Sterilization in packages is also not possible. The 2004 regulations declassified this device as an auxiliary unit.

Class S autoclave

It is an intermediate class between class N and B. In this type of autoclave it is possible to sterilize most of instruments, except those of capillary construction. Class S allows the sterilization of more complex items, as well as single, multilayered and solid instruments which cannot be sterilized in class N autoclaves. In addition, it is possible to remove the air from the autoclave’s chamber completely by built-in vacuum pump. However, due to the use of a single-stage pre-vacuum in these models, the process is less effective than in class B autoclaves. Class S autoclaves are used in medical facilities that do not need complex, recessed tools, for example in primary healthcare facilities, as well as in hairdressing salons, beauty salons and tattoo studios. In S autoclaves it may be also possible to conduct the sterilization of liquids, which is applicable in microbiology laboratories.

Class B autoclave

The most advanced devices available on the market are class B autoclaves, commonly called medical autoclaves. They can sterilize all types of instruments, packed and unpacked, even the most complex ones. The Enbio S autoclave has been classified as a class IIB medical autoclave according to European Directive 93/42/EEC. In accordance with the classification provided in EN 13060, the following medical tools may be sterilized in this type of devices: solid batches, small porous items, small porous batches, full porous batches, simple hollow items, items with narrow clearance, multiple packaging that may be unpacked or packaged. Unlike autoclaves of other classes, these devices are equipped with a fractionated pre-vacuum, which allows complete air removal and steam injection. This is the best currently available technique of sterilizing any type of product. They are also equipped with USB ports to archive the conducted processes in electronic form. Such instruments as catheters, speculum, needles and dental tips can be effectively sterilized only in this class of device. The class B autoclave is used in dental facilities, primary healthcare facilities, beauty and wellness centres, as well as in veterinary practices, tattoo studios, piercing studios and hairdressing salons. Autoclaves are also commonly distinguished according to their place of usage – there are:

In fact, there is no such division from professional or technical point of view. Any autoclave certified for medical purposes will apply in various facilities. Autoclaves used in medical and beauty facilities are the top class devices – class B autoclaves, i.e. medical autoclaves. These devices are used both in hospitals, and in tattoo and piercing studios. Autoclaves of various capacities are available on the market. The most common choice for beauty salons is 8 liter autoclave or even smaller one. They are quite compact in size, but very capacious – they can fit even several packages with tools. Autoclaves with a larger capacity, for example 18 l, 23 l, are used in larger facilities. 

Sanitary-epidemiological rules and equipment sterilization

Beauty salons in more and more countries must obey strict rules about disinfection and sterilization of their equipment. However, the law in UK does not require beauty salon to have an autoclave for reusable equipment sterilization. It is recommended to wash the equipment in hot water with soap and then provide disinfection using specified solution intended for disinfection. The only institution which establish constraints about hygiene in beauty salons is HABIA (Hair and Beauty Industry Authority). The British Government recognizes HABIA as the organization responsible for creating standards for beauty salonsand hairdressing salons. People providing these kind of services are obliged to follow the rules written in Code of practice in nail services. This document embraces such issues as sterilization, disinfection, first aid and rules of equipment storage 3. The condition of legal requirements is reflected in statistics. The surveys conducted in 2008, published by Health and Safety Laboratory show that basic rules of hygiene are not abided. For example, half of interviewees admitted that they use single-usage tools multiple times. Meanwhile, the most common types of infections occurring in such facilities are:

  • viral infections (hepatitis B virus, hepatitis C virus, human papillomavirus HPV, HIV);
  • bacterial infections (mainly staphylococcal and streptococcal);
  • fungal infections (Pityrosporum ovale, Candida sp. , Epidermophyton sp.);
  • parasitic infections.

Although British law does not impose sterilization obligations, it is worth to taking better care of the health of customers and employees. Tools which are not disposable must be washed, then disinfected and finally sterilized to ensure complete safety during the service. The sterilization process destroys all viruses, fungi and bacteria. The feature that distinguishes the class B autoclave from other devices available on the market is the possibility to sterilize any type of instruments, including those with a porous surface. A class B device is a top-notch device that also meets medical requirements. Only autoclave sterilization gives complete assurance of sterility of equipment. To ensure that the autoclave works properly, a vacuum test must be performed every day. In addition, sterilization records must be kept and an indicator must be used for each sterilization. Once a month, it is necessary to take a test on so-called “sporal A”. The sporal A is placed in an autoclave and then routinely sterilized. After the end of the dispute, it should be returned to the laboratory for testing to confirm the correct functioning of the autoclave. 

Where should the autoclave be implemented and why?

As we already know the legal requirements, let's take a look at the instruments that need to be sterilized in particular places:

  • beauty parlour – pliers, hooves, tweezers, cutters, scissors, reusable files;
  • tattoo parlour, piercing parlours – all reusable tools such as piercing tongs, tubes, earrings, jewelry, griffins and tattoo beaks;
  • dental facility – impression spoons, surgical instruments, contra-angle handpieces, rectifiers;
  • aesthetic medicine facility – all reusable tools;
  • podology parlour – scissors, clippers, hooves.

It is also reasonable to have an autoclave for veterinarians using reusable tools, hairdressers and barbers who use reusable metal razors and scissors that may come into contact with blood and body fluids.

Autoclave with or without a printer?

There are many types of autoclaves available on the market and some of them even have a printer. They are not obligatory features though, as the necessary data can be collected and stored electronically. Enbio autoclaves are equipped with a flash drive collecting data on sterilization processes. The data is automatically stored on a USB drive, then it can be downloaded to the computer and freely printed.