DIN EN 13060 defines three classes of small steam sterilizers. The KRINKO/BfArM Recommendation 2012 requires Class B for all instruments classified as Kritisch A and Kritisch B — the vast majority of dental and podiatric instruments. For tattoo studios, Class B is the state of the art. Choosing the wrong class means your instruments may not be sterilized.
DIN EN 13060, the German adoption of the European standard EN 13060, classifies small steam sterilizers into three classes based on their steam penetration capability and the load types they can process. This classification determines which instruments each autoclave can sterilize and, therefore, which class is appropriate for each profession. The MPBetreibV (Medical Devices Operator Ordinance) Section 8 requires the use of standards-compliant reprocessing equipment -- the Vermutungswirkung (presumption of conformity) under Section 8(2) only applies when recognized standards of technology are followed.
Class B (Big autoclave, small sterilizer) is the most versatile class. It features a fractionated pre-vacuum system that evacuates air from the chamber and from the internal channels of hollow instruments (dental turbines, contra-angle handpieces, cannulae) before steam injection. Only Class B can reliably sterilize wrapped loads, hollow instruments, and textiles.
In Germany, Class B is effectively mandatory for dental practices: Kritisch-B (critical B) instruments -- those with lumens -- require a Class B autoclave and prior machine cleaning and disinfection (RDG -- Reinigungs- und Desinfektionsgeraet) per DIN EN ISO 15883, as specified by the KRINKO/BfArM Recommendation. The DAHZ Hygieneleitfaden (16th edition, 2024 -- Dental Hygiene Guidelines) recommends Class B as the standard for all dental offices. For tattoo studios using hollow instruments, Class B is likewise the only safe choice.
Class N (Naked) can only process solid, unwrapped, non-hollow instruments. There is no pre-vacuum -- air displacement occurs by gravity, which is insufficient for hollow instruments or wrapped loads. Instruments sterilized in a Class N autoclave must be used immediately after the cycle, as they lose sterility upon contact with ambient air without packaging.
In German practice, Class N has very limited application: it does not allow sterilization of wrapped instruments (no use-by date possible), cannot process hollow instruments, and does not provide the traceability required by the MPBetreibV and the KRINKO/BfArM Recommendation. Its use is restricted to immediate sterilization of emergency instruments.
Class S (Specified) is an intermediate category defined by the manufacturer's specifications. The manufacturer declares which load types their Class S autoclave can process (e.g., "solid wrapped instruments" or "hollow type A instruments"). The available cycles and permitted loads vary from model to model -- there is no single standard for Class S.
Before purchasing a Class S autoclave, it is essential to verify that the manufacturer's declared cycles cover the specific requirements of your practice. When in doubt, Class B is always the safest choice: it covers all load types and avoids the risk of using an unsuitable cycle for a particular instrument type.
Regardless of class, every autoclave must undergo regular controls: a daily Bowie-Dick or Helix test before the first load (mandatory for Class B and Class S with pre-vacuum, per KRINKO/BfArM 2012), chemical indicators in every load, weekly biological indicators (spore tests with Geobacillus stearothermophilus), a weekly vacuum leak test (Class B), and maintenance per the manufacturer's instructions. For details on mandatory controls, see the biological controls guide.
Dental practices: Class B effectively mandatory -- rotary instruments (turbines, contra-angle handpieces) are hollow and must be sterilized wrapped. The standard cycle is 134 degrees C for 18 minutes (prion cycle). The KRINKO/BfArM Recommendation additionally requires machine pre-cleaning in an RDG for Kritisch-B instruments.
Tattoo, piercing, and permanent makeup: Class B recommended per DIN EN 17169:2020 and DOT e.V. hygiene guidelines. State-level Hygieneverordnungen require sterilization of reusable instruments -- Class B enables wrapping and assignment of a use-by date.
Podiatry: Class B recommended for all invasive instruments. Surgical instruments (scalpels, curettes, gouges) must be sterilized wrapped to maintain sterility until use. For details on load documentation requirements, see the traceability sheet guide.
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