Class B autoclave: selection criteria and maintenance

01Class B, N or S: what the EN 13060 standard says

The EN 13060 standard applies to small steam sterilisers and distinguishes three types of cycle (summary of the EN 13060 standard):

• Type B: sterilisation of all wrapped or unwrapped, solid, hollow and porous products, as represented by the test loads in the standard.
• Type N: sterilisation of unwrapped solid products.
• Type S: sterilisation of products specified by the steriliser manufacturer.

Newmed offers models in all three classes and states that the choice between B, S and N depends on your needs (Newmed Kronos & Tiche catalogue FR, R2 12/2023, p. 5). Its brochure specifies that hollow instruments are type A and B within the meaning of EN 13060 (Newmed Kronos Class B brochure, FR, p. 4). In a dental practice, where wrapped instruments and hollow instruments are sterilised, this is why a Class B autoclave is sought.

The Newmed Kronos B18 is a Class B benchtop autoclave, CE certified in accordance with Regulation (EU) 2017/745 and designed to the EN 13060 standard (Newmed catalogue 2023, p. 15).

02The criteria for comparing two autoclaves

1. Chamber volume and depth

Newmed presents the 18-litre chamber as suited to small and medium-sized practices, and the deeper 23-litre version (530 mm) to higher throughput and larger kits. A 6-litre version is also available (Newmed Kronos Class B brochure, p. 3; Newmed catalogue 2023, p. 4).

2. Maximum load

Source: Newmed Kronos & Tiche catalogue FR, R2 12/2023, p. 15.

3. Available cycles and tests

The Class B Kronos models offer a choice of 10 cycles, so that water and electricity consumption can be matched to the load (Newmed catalogue 2023, p. 5).

4. Water

"Good-quality steam can only be obtained from good-quality water," writes Newmed (Kronos Class B brochure, p. 3). On the Kronos 18 and 23, a front-mounted water pump fills the unit from a tank placed on the floor, and draining can be manual or automatic. As an option, the ROSI system integrates reverse osmosis into the unit so that it can be connected to tap water (Newmed catalogue 2023, pp. 5-6). Newmed also offers water treatment accessories: Osmo3, AquaMed, Perfect Water, and the Green Control meter (TDS in ppm, conductivity in µS/cm, temperature) (p. 18).

5. Traceability and safety

A printer, optional data logger on USB stick, automatic door locking, water quality monitoring and maintenance reminders are described by Newmed (catalogue 2023, p. 5). Standby mode activates after 60 minutes and a delayed start is possible (p. 5).

03Which cycle for which load?

For the Class B Kronos B18, the Newmed catalogue lists the following cycles: Helix test, Bowie-Dick test at 134 °C, vacuum test, wrapped hollow at 134 °C and 121 °C, Prion at 134 °C, wrapped solid at 134 °C and 121 °C, porous at 134 °C and 121 °C, fast at 134 °C and 121 °C, unwrapped hollow at 134 °C (Newmed catalogue 2023, p. 14). The stated sterilisation (plateau) times are 5 minutes at 134 °C, 18 minutes at 121 °C and 20 minutes for the Prion cycle (p. 14).

The Newmed selection guide for the B18 suggests the following reasoning (Newmed, Cycle Selection Guide B18):

The total duration of a cycle depends on preheating, drying, the load and the electrical supply (Newmed catalogue 2023, p. 14): refer to the unit's display and its manual.

04Testing and documenting sterilisation

Newmed describes the role of each test and indicator (Newmed catalogue 2023, p. 19):

• Bowie-Dick test: detects correct steam penetration into a porous load.
• Helix test: monitors steam penetration into a lumen-type device (1 helix + 250 indicators per pack).
• Steam process indicators: colour-change check (250 per pack).
• Steam integrating indicators: verify sterilisation at 134 °C and 121 °C (250 per pack).
• Biological indicators: determine whether the conditions for eliminating micro-organisms have been reached (10 per pack), with the Pulcino incubator.

The Kronos B18 also has a vacuum test cycle (p. 14). Test frequency is a matter for your practice's quality procedure and the manufacturer's instructions.

To keep records, the printer and USB logger make it possible to document and monitor sterilisation processes; for older Newmed autoclaves, the STS Datalogger transfers data to a computer (pp. 5 and 19).

05Maintaining a Newmed Kronos B18

Newmed organises maintenance in kits, according to the number of cycles performed. The Newmed price list designates the service kits as follows (Newmed price list 2025):

The unit displays maintenance reminders and monitors water quality (Newmed catalogue 2023, p. 5); when the ROSI cartridges are nearing the end of their life, the software sends a notification (p. 7). ROSI consumables kits and Osmo3 cartridges are also listed in the Newmed price list 2025.

Day to day

• Use water of suitable quality and watch for water quality alerts.
• Empty the waste water tank (4 L) before it is full.
• Load without exceeding the maximum masses for the class used.
• Choose the cycle according to the load (table above) and archive the reports.

Newmed offers a 3-year warranty, subject to conditions (catalogue 2023, p. 5). For commissioning, original maintenance kits and Newmed parts, contact AxeMed. Complementary hygiene products are on the Hygiene and sterilisationpage.

→Products mentioned

Newmed Kronos B18 autoclave – Class B steam steriliser, 18-litre chamberRef. KRB10000SA100405 739,00 € excl. VATIDactiv Instrument Disinfectant 1 Litre Dosing BottleRef. BOS984217,49 € excl. VATAldena blue nitrile examination gloves, powder-free – size M, box of 100Ref. NRB32M3,39 € excl. VAT

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