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An autoclave is a steam sterilisation device that is primarily used in medical facilities, laboratories, dentistry and the food and pharmaceutical industries. Its main purpose is to completely kill microorganisms such as bacteria, viruses, fungi and even heat-resistant spores in order to reliably sterilise instruments, materials or liquids.
The terms distilled water, demineralised water and demineralised water (fully demineralised water) are commonly used. Distilled or demineralised water as specified by the manufacturer to prevent limescale/corrosion and ensure process reliability. While distilled water (distilled water) is a term that implies treatment by evaporation and condensation of the water, demineralised water means that there are no minerals in the water that could damage the autoclave or the instruments. The same applies to demineralised water. The respective water quality assumed for these three terms may well be identical. Demineralised water or demineralised water is usually produced using water treatment systems based on the principle of ion exchange or reverse osmosis.
The requirements for demineralised water are defined in DIN EN ISO 13060 and DIN 285. A corresponding reference on the labels of the canisters gives you certainty about the suitability of the demineralised water for sterilisation.
Fill the water into the storage tank of the stand-alone autoclave. Before each programme start, the water quality is checked by measuring the conductivity. The autoclave issues a warning message if the water quality is 40 µS and an error message if it exceeds 60 µS. If there is water of insufficient quality in the storage tank, it is not possible to start the programme. The abbreviation µS stands for microsiemens. The unit of measurement defines the electrical resistance via the quantity of dissolved particles in the water.
The automatic supply of feed water to MELAG autoclaves has become established in almost all practices. The water treatment systems of the MELAdem series are available for this purpose. The MELAdem 47 works according to the reverse osmosis process and the MELAdem 40 and MELAdem 53 according to the ion exchange process. Once the tap water has been treated, you have optimum demineralised water with a conductivity of between 1 and 5 µS for sterilisation.
Maintenance and validation of an autoclave must be carried out regularly in order to ensure long-term safe sterilisation. Maintenance is usually carried out every two years or a specified number of cycles in accordance with the manufacturer's specifications and includes functional checks and the replacement of wearing parts. Validation or performance checks are carried out at specified intervals, usually also every two years, and additionally whenever relevant changes occur - for example, after repairs to relevant components, after adjusting process parameters or loading patterns.
Together, these measures ensure that the autoclave works reliably and that all sterilisation processes are reproducible and conform to standards.
International hygiene guidelines specify the performance of maintenance services to guarantee the reliable operation of the steam sterilisers. Only technicians with requisite training may be entrusted with performing this service task. Steam sterilisers and
washer-disinfectors are usually equipped with maintenance counters, which issue a maintenance message after completing a specified number of cycles or time interval.
Other manufacturers of autoclaves use different maintenance sets and spare parts. During the product development stage, MELAG places considerable value on sustainability, thus aiming to minimise the numberof spare parts for later maintenance while also reducing service times.
The most important maintenance task performed on MELAG products is the inspection of all relevant components ensuring the functionality of the device, as well as the replacement of wear parts.
MELAG-trained technicians perform the maintenance measures quickly whilst seeking to minimize costs. The obvious advantage of using the MELAG system solution is that the maintenance can be performed quickly and most of the time in one sitting. However, the associated cost-savings are not achieved when setting up a multi-brand decontamination workflow that requires different service technicians to carry out inspection at different times of the year on different devices. MELAG offers a hassle-free, co-ordinated and cost-friendly
alternative.
In addition to maintenance costs, the consumption costs for energy and water drive up the cost of steam sterilisation. MELAG engineers attach significant importance to achieving low consumption figures without a loss in quality. Additional costs can also result from unforeseen repairs of the autoclaves. MELAG stands for quality “Made in Germany”. Our entire product range is produced exclusively in Berlin. With over 160 R&D, IT and testing engineers, we strive daily to improve quality. MELAG products have developed a reputation for being reliable, user friendly and low maintenance. Taking into consideration all the costs incurred throughout the devices life span, the total cost of ownership of MELAG devices is significantly lower than that of their competitors, even those initially retailing at lower prices.
Get in our video tutorial all important information about the correct loading of the autoclave / steriliser. The video tutorials for the compilation of an individual loading pattern can be found on our Multimedia channel.
Successful sterilisation requires correct cleaning and disinfection of the instruments.
Please always comply with the reprocessing instructions from the instrument manufacturer. When performing instrument care, it is imperative not to use water-repellent care products or water-impermeable oils. Use only those care agents suitable for steam sterilization.
Correct loading of the autoclave is a prerequisite for effective sterilization and best drying results. In this regard, please comply with the following principles while loading the autoclave:
Place textiles on the top tray
Place the sterilisation containers at the bottom
Place unwrapped instruments at the bottom
Place heavy loads at the bottom
Place sterilisation packaging (foil and paper pouches) on the top trays. Except when sterilising in combination with textiles: In this case, place them at the bottom.
As far as possible, sterilisation pouches should be placed in an upright position in the steam steriliser. If you place the sterilisation packaging directly on a tray, make sure that the film side faces upwards to prevent the development of water droplets.
The fractionated vacuum used by Class B autoclaves also permits the sterilisation of double wrapped instruments e.g. instruments wrapped in two pouches or in a pouch and a sterilisation container. Closed sterilisation containers (preferably made of aluminium) must be perforated on at least one side to permit steam injection. The MELAstore-Boxes and the MELAG sterilisation containers ensure the best-possible sterilisation and drying results.
Regularly checking the autoclave is an important part of hygiene management in practices and clinics.
Testing sterilisers using bioindicators used to be carried out every six months or after 400 sterilisation batches. However, this requirement originates from an outdated chapter of DIN 58946-6, and the updated standard DIN EN ISO 17665-1 does not include a corresponding reference to the use of bioindicators.
Biological indicators such as spore tests are not suitable for assessing the sterilisation process. This is because sterilisation requires a longer holding time than is necessary to kill the biological indicators.
The use of a suitable indicator system is recommended in order to monitor sterilisation on a batch basis. The sterilisation result of hollow instruments is checked with a Helix test body. As a system provider, MELAG offers you the two helix test devices MELAcontrol Helix and MELAcontrol Pro for functional testing of its class B autoclaves. Both test devices fulfil the requirements of EN 867 - 5. Please test class S autoclaves with a class 5 indicator.
Daily routine tests are required for the safe operation of an autoclave. These include the vacuum or leak test, which checks for leaks and correct negative pressure generation, as well as the Bowie thickness or helix test, which verify correct vapour penetration and air removal. These tests are carried out regularly before the sterilisation cycles and must be fully documented to ensure process reliability.
In addition, the performance assessment within the validation shows that the sterilisation parameters have also been achieved at the load in the autoclave. Validation is therefore a check of the sterilisation success with practice-specific sterilisation material, sterilisation packaging and loading at the autoclave installation site. To ensure successful sterilisation in the long term, this performance assessment must be repeated at regular intervals in the practice and clinic.
Depending on the model, MELAG autoclaves have several standardised sterilisation programmes that are adapted to different materials and load types. The universal programme at 134 °C is used most frequently, which is suitable for both wrapped and unwrapped instruments and is the standard in most practices. For instruments that are available more quickly, a fast programme at 134 °C is available, which is specially designed for unwrapped items. For more sensitive materials such as certain plastics, the gentle programme at 121 °C is usually used, which works at a lower temperature but with a longer holding time. Many MELAG autoclaves also offer a prion programme at 134 °C, which meets particularly high safety requirements. Depending on the model, there are also special programmes for liquids or for special documentation and drying requirements. Overall, the choice of programmes enables sterilisation to be tailored precisely to the material, packaging and area of application.
With a vacuum test, steam sterilisers monitor how well all steam-carrying parts are sealed. This test is carried out in accordance with DIN 58946-6: 2002 and is thus prescribed by the national hygiene regulations.
If you operate a large autoclave (>1 STU), we recommend carrying out this test on a monthly basis. For a table-top steam steriliser, the test is recommended to be carried out once a week. Ideally, this will be done on Monday morning before work starts, as a cold sterilisation chamber without loading is required.
To start the test, remove the tray mount from the sterilization chamber and check if it is dry. After closing the steam steriliser, use the control panel to select the vacuum test. Now the air will be evacuated from the chamber of the autoclave. The test starts automatically after pressure equalisation has taken place. During the test, the pressure change within the chamber per unit of time is measured to see how much air enters the unit during. If the leak rate exceeds a certain value, the autoclave will issue a malfunction message on the display. If the test is successful, you can start with the instrument decontamination process.
Learn more about routine tests for an autoclave in our video-tutorial.
Daily or regular routine tests must be carried out in accordance with the applicable standards and manufacturer's specifications. These include in particular the Bowie-Dick test or helix test to check air removal and steam penetration as well as the use of chemical indicators in each batch. If necessary, biological indicators must also be used in accordance with official and standard specifications. All test results must be documented and archived in a traceable manner.
The Bowie-Dick test must be carried out every working day before the first sterilization. It serves as proof of sufficient air removal and uniform steam penetration in the sterilizer and must be documented.
The use of a helix test device is particularly necessary for batch control when reprocessing medical devices of category "critical B". This simulates complex hollow instruments and ensures that even lumens that are difficult to access are sufficiently sterilized. The results must also be documented for each batch.
Fractionated pre-vacuum is a process used in modern autoclaves in which the air in the sterilisation chamber is not removed in a single step, but through several successive vacuum and steam pulses. This repeated sequence is particularly effective at displacing air from cavities, narrow lumens and wrapped instruments, allowing saturated steam to reach all surfaces safely and completely. This process is crucial for the sterilisation of hollow bodies and complex instruments, as even small air residues would block the entry of steam and thus impair the sterilisation effect.
Modern class B autoclaves generally require between 15 and 45 minutes per sterilization cycle, depending on the load type, load quantity and selected program. Shorter running times are possible, particularly with optimized fast programs and low loads, while complex loads (e.g. hollow instruments or "critical B" products) require longer cycle times.
To increase energy efficiency, current appliances have various technical functions such as eco programs, intelligent standby modes and heat recovery systems. These significantly reduce energy and water consumption in everyday practice, especially with irregular use or between sterilization cycles.
Targeted load optimization also helps to increase efficiency: By utilizing the sterilization chamber sensibly and adapting the programs to the respective load, cycle times can be shortened, resources conserved and process economy improved without compromising the validity of sterilization.
EN 13060 is particularly important for small steam sterilisers, as it defines the technical requirements, test methods and performance characteristics of these device classes. Among other things, it specifies which sterilisation cycles are permitted, how the devices must be designed and how their effectiveness must be verified. In addition, various national hygiene recommendations and legal requirements apply in Germany, in particular the guidelines of the RKI and KRINKO/BfArM, which describe in detail how medical devices must be reprocessed and which quality and documentation standards must be complied with. In addition, depending on the facility, further regulations on occupational health and safety, water quality and the validation of reprocessing processes apply. Taken together, these standards and regulations ensure that autoclaves are operated safely and that reproducible, standard-compliant sterilisation is achieved.
Hollow bodies can only be safely sterilised if an autoclave has class B cycles with fractionated pre-vacuum, as these processes reliably remove the air from narrow lumens and thus enable complete steam penetration. Equally important is the correct packaging, such as special sterilisation films or cassettes that allow steam to pass through. The instruments must be arranged in such a way that openings are unobstructed and no kinks or blockages occur. A helix test, which simulates the penetration of long, narrow cavities, is regularly used to check process reliability. In addition, the manufacturer's instructions for straight and contra-angle handpieces and other sensitive hollow instruments should always be observed, as these often contain specifications for cleaning, lubrication and sterilisation parameters.
The process documentation of the autoclave is essential as proof that a sterilisation programme has been successfully completed. Documentation can be carried out manually or digitally using a software solution. In our video tutorial, you can find out more about the integrated documentation and release of the sterilisation batch with our premium-class autoclaves.
Manual documentation and release are carried out using a documentation sheet from our MELAdoc series. The release decisions are recorded on this sheet by hand. You can further simplify the documentation process with the help of the MELAdoc label printer.
Release after sterilisation begins with checking and documenting that the process has been carried out correctly. The relevant process parameters are stored in a log and the success of the batch is shown on the autoclave display. In addition, the sterilisation packaging is checked for integrity and dryness, and finally the sterilised items are labelled. Please always label the packaged instrument behind the seal seam on the film side of the sterilisation packaging. After using the instrument, you can remove the label from the film packaging and transfer it to the patient file. This documentation completely fulfils the reverse burden of proof in your medical or dental practice.
The release of the sterilisation batch on the documentation sheet includes the following points:
Personnel, device and batch number Sterilised on / Usable until Programme / Load Successful sterilisation: Yes / No Batch indicators (e.g. MELAcontrol Helix) OK: Yes / No Release granted: Yes / No Signature for release
The reprocessing logs can be output to a storage medium, such as the MELAflash CF card, for data backup. No additional software is required to open the logs. The files can be opened with a word processing program (Word or text editor). Please observe the statutory retention periods when storing the release documents.
MELAtrace fulfils the requirements for complete documentation and release quickly, securely and paperlessly. The software solution links the reprocessing steps of cleaning and disinfection with sterilisation to ensure comprehensive and complete documentation of instrument reprocessing. MELAtrace guides you step by step through the programme. The batches are released via the system and the labels for identifying the instruments are printed out via the MELAprint 60. By scanning barcode labels, digital assignment in patient management software is even ensured.
Further information on the documentation and release of instrument reprocessing can be found here.
The regular chamber cleaning of your autoclave is an important step of the instrument reprocessing workflow and enables a long-term protection of the device.
For ideal cleaning results and long-lasting shine the MELAG Chamber Protect cleaning set should be applied to the autoclave once a week.
The cleaning set, including the Chamber Protect spray, 50 lint-free cloths and 1 microfibre cloth saves the chamber from discolouration and depsosits and removes even soiling that is invisible to the eye. Approved through extensive material compatibility tests it is particularly gentle on the material of the chamber and door seal and therefor ideally matched to all MELAG steam sterilizers.
Before starting the chamber cleaning, the autoclave should be switched off and cooled down. The Chamber Protect Spray is then sprayed onto the sterilization chamber and the inside of the door and is spread with a lint-free cloth.
After a short exposure time (approx. 3 minutes), the stainless steel surfaces are moistened with demineralised water and then wiped with another cloth that has also been moistened. After a further 5 minutes exposure time, the sterilisation chamber and the inside of the autoclave door should be dried with the microfiber cloth.
The cleaning set can be applied to your autoclave as well as to all of your trays.
The process documentation of the autoclave is vital as verification of a successfully completed sterilisation program. The documentation can be done manually as well as digitally using a software solution. Learn more about the digital documentation and approval process via the colour-touch Display of the Premium-Class Evolution in our video-tutorial.
Manual documentation and approval takes place with the help of a documentation sheet from our MELAdoc articles. The approval decisions are then recorded by hand. With the help of the MELAdoc label printer, you can further facilitate the documentation process.
After sterilisation, batch approval begins with the review and documentation of the correct process. The relevant process parameters are saved in a log file and the success of the batch is displayed on the autoclave’s display. In addition, the sterilisation packaging is checked for integrity and dryness, and finally the labeling of the sterilised material takes place. Please always mark the wrapped instruments behind the seal seam on the foil side of the sterilisation packaging. After using the instruments, you can remove the label from the foil packaging and transfer it to the patient record.
The approval of the sterilisation batch on the documentation sheet requires following information:
Personnel-, equipment- and batch number
Sterilised on / Usable until
Program / Loading
Successful sterilisation: yes / no
Batch indicators (e.g. MELAcontrol Helix) OK: yes / no
Release granted: yes / no
Signature for release
The log files may be stored on an output medium, such as the MELAflash CF card, for data backup. No additional software is required to open these files. The log files can be simply accessed with a word processing software (e.g. word or text editor). Please note the legal retention periods when storing the approval documents.
MELAtrace meets the requirements for complete documentation and approval quick, secure and paperless. The software solution combines sterilisation, cleaning and disinfecting steps to ensure comprehensive and complete documentation of instruments reprocessing. MELAtrace guides you step by step through the approval process. The batches are released via the system and the labels for marking the instruments are printed out via the MELAprint 60. Scanning barcode labels even ensures digital assignment in a patient management software.
Learn more in our video tutorial about the correct filter exchange procedure for the MELAdem 40 water treatment system:
Watch now
The MELAdem 40 water treatment unit supplies the steam steriliser with demineralised water. The Evolution series automatically tests the conductivity of the demineralised water during every sterilisation procedure and issues a warning if the water quality is too low. Please change the mixed-bed resin cartridges as soon as the warning is displayed. Before changing the cartridges, please close the tap of the water line. Then start the Universal-Program and abort it after c. 20 seconds. You can now open the cartridge container using the wrench in the housing cap of the MELAdem 40. Please slide the wrench over the cartridge container and turn it clockwise.The water in the cartridge container can be poured into the drain and the exhausted cartridges can be disposed of in the domestic waste. Please insert the new cartridge in the thoroughly rinsed cartridge container and screw the container tight by hand and then with the wrench. Repeat this procedure for the second mixed-bed resin cartridge. After you have re-opened the water tap and have checked the MELAdem 40 for leaks, your steam steriliser and water treatment unit are ready to use.
Our decades of development experience and focus on the instrument reprocessing segment are the basis for our innovative and permanently reliable products - made in Germany. Learn more about the differences between Premium and Pro-Class autoclaves in the following section:
The advantages of the Premium-Class Evolution
✓ Record operating times: Very fast cycle times of 10 to 25 minutes due to the patented double-jacket technology
✓ Intelligent drying DRYtelligence: Optimum drying results and an 80 % reduction in drying time
✓ Very high loading capacities: For up to eight trays and 9 kg
✓ XXL Colour-Touch Display: Intuitive user interface with integrated software for documentation and approval
✓ Documentation interfaces: CF card slot and two network interfaces in the device at no extra cost
✓ Video Tutorials: how to use the autoclave explained quickly and easily with video tutorials
✓ MELAconnect App: Access the autoclave status and program progress at any time via mobile app
✓ Customized to your decontamination room: As a stand-alone solution or autoclave with fixed water connection in chamber sizes 18 and 24 litres
Discover the product highlights in our video of the Premium-Class Evolution.
The advantages of the Pro-Class
✓ Short operating times: Fast cycle times from 20 to 50 minutes
✓ High loading capacities: For up to 6 trays and 7 kg
✓ Intuitive operation: With MELAG four key concept
✓ Serial interface: For paperless documentation with MELAflash or MELAnet Box
✓ Customised to your decontamination room: As a stand-alone solution or autoclave with fixed water connection in boiler sizes 17, 23 and 29 litres
✓ Vacuklav 24 BL+: With 60 cm chamber depth for sterilization of extra-long instruments such as endoscopes
Discover the product highlights in our Pro-Class video.
Hygiene measures to prevent infection are more important than ever in times of COVID-19. In medical practices and clinics, special attention must be paid to the reprocessing of instruments in addition to the new distancing and hygiene rules. This is because sterilisation is the only way to completely inactivate all pathogens capable of reproducing and thus achieve absolute safety for patients and the team.
Numerous questions arise when choosing an autoclave. In terms of reliability, effectiveness and a wide range of applications, there can only be one answer for a medical practice: Sterilisation with saturated steam at 134 degrees Celsius. Steam sterilisation enables rapid reprocessing of unwrapped and wrapped instruments using a reproducible process. With the help of the integrated process documentation, legally compliant proof of error-free reprocessing can be provided.
Air inhibits sterilisation and must be removed from the chamber and the hollow bodies of the instruments in advance. DIN EN ISO 13060 classifies autoclaves according to their evacuation capacity into classes B, S and N. The type and complexity of the instruments determine which sterilisation process is suitable. For hollow instruments and packaged instruments, a class B autoclave with fractionated pre-vacuum is the state of the art and the first choice for studios.
The fractionated vacuum process of a class B autoclave reduces the air in the sterilisation chamber by repeatedly evacuating the air and allowing steam to flow in. This process guarantees optimum saturated steam conditions for sterilising not only solid and porous instruments, but also complex hollow instruments such as handpieces and endoscopes.
Watch the video to find out more about the sterilisation process in a class B autoclave.
Sterile pouches only remain sterile if they are removed from the autoclave completely dry and undamaged after the sterilisation process, as moisture or tears would impair the barrier effect. They must then be stored in a cool, dry and dust-free place, ideally in closed cabinets, and the shelf life and recommendations of the packaging manufacturer must be observed. If sterile bags are still damp after the cycle, this is often due to overloading, unsuitable or too tightly packed packaging, instruments stacked too tightly or insufficient drying time. Damp pouches are not considered sterile and must therefore not be used; instead, loading, packaging material and drying phase should be checked and optimised to ensure completely dry, safe sterile supply in the future.
The sterile goods must not be released if there are error codes or wet packs; the batch must be labeled and documented. The relevant influencing factors must then be systematically checked (water quality, filters, seals, loading, packaging, drying and vacuum performance). The cycle logs must be read out and evaluated. The MELAG Troubleshooting Portal should be used for support(https://www.melag.com/service/troubleshooting). If necessary, contact the service department or manufacturer.
Batch protocols, barcode data and user logins are automatically transferred to the practice network, a DMS or reprocessing software via LAN, WLAN or USB. Data processing is carried out in compliance with the applicable data protection requirements (GDPR).
Steam sterilization is characterised by a fast and gentle effect on materials, enables reliable penetration of even complex cavities and is therefore considered the standard procedure for reprocessing medical devices. In contrast, hot air sterilization (dry heat) is significantly more time-consuming and can place greater stress on materials.
Air inhibits sterilisation and must be removed from the chamber and the hollow bodies of instruments. The pre-conditioning phase comprises a conditioning and (as required) an evacuation phase. Steam is injected during the conditioning phase generating over-pressure in the sterilisation chamber. The Class B or Class S steam steriliser then evacuates the resulting air-steam mixture. This process is repeated in the autoclave up to three times. The air removal phase ensures that no air remains in the sterilisation chamber and the inside of hollow body instruments
The continuous introduction of steam generates a pressure and temperature increase in the sterilisation chamber.
The sterilisation phase starts as soon as the program-specific sterilisation parameters have been achieved. Typically, the load is exposed to a set temperature of 134 degrees °C for a holding time of 5.5 minutes. Heat or moisture-sensitive instruments and textiles can be
sterilised using the Gentle-Program with a temperature of 121 °C for a holding time of min. 20.5 minutes.
Pressure is released from the sterilisation chamber through an exhaust valve after the holding time is reached.
Depending on what sterilisation method is used, the instruments and packaging are dried using either vacuum drying or high-pressure drying.
Upon completion of the sterilisation program, autoclaves using Class B or Class S programs draw ambient air into the steam steriliser chamber through the air filter, thus the steriliser chamber is exhausted to atmospheric pressure. It is now possible to open the steam steriliser
door and remove the reprocessed instruments.
