Practice Example // Reprocessing

Use without personalization

Together with experts in medical technology and hygiene, Helios Kliniken GmbH has developed a safe procedure for reprocessing FFP2 and FFP3 masks. According to their own statements, the processing method exceeds the security level specified by the Robert Koch Institute (RKI) and allows masks to be reused without personalization.

Clinics and other healthcare facilities are still complaining about bottlenecks in personal protective equipment for their employees – there is a lack of high-quality FFP2 masks and FFP3 masks in particular. The methods of reprocessing that are currently being discussed are either considered to be not safe enough or require masks to be personalized before they are used again – a requirement that cannot be met by most healthcare facilities, either technically or logistically.

Now Helios Kliniken, together with experts in medical technology and hygiene, have developed a reprocessing procedure that allows healthcare workers to reuse masks without personalization and yet guarantees a high safety standard. The procedure was shared online in order to help other healthcare facilities to reprocess respiratory masks in a safe and at the same time practicable way.

There are several steps to the procedure:

  • Drying the masks according to the recommendations from the RKI for 35 minutes at 70 degrees in washer-disinfectors
  • Processing in recirculated air convectors at 70–75 degrees for a total of nine hours

Both procedures together achieve a processing value which corresponds to the value A0 of 3000. Such a high A0 value also includes the safe inactivation of thermostable viruses. For comparison, the procedure described by the RKI only achieves an A0 value of 60.

The experts at Helios were able to prove that SARS-Cov-2 and other pathogens can be safely inactivated with the procedure. This meant that FFP2 masks and FFP3 masks no longer had to be reused in a personalized way.

Process instruction by Helios Clinics Germany

PDF download info diagramm

Step 1: Collection

Collecting masks used for protection against Covid-19, sorting out and disposing of visually damaged or soiled masks. Masks worn in connection with TBC (tuberculosis patients) are destroyed directly*.

Step 2: Transport to Central Sterile Services Department (ZSVA)/Processing Unit for Medical Devices (AEMP)

Transporting the masks to the Central Sterile Services Department or to the Processing Unit for Medical Devices in suitable containers (or equipment that is similarly used).

Step 3: Quality Control

Inspect the masks again for contamination and damage.

Step 4: Thermal Processing

Pre-treating the masks according to the recommendations from the RKI: Drying/heating in washer-disinfectors that are already available to at least 65 degrees with a holding time of 35 minutes. The total process time is just under one hour and takes into account the time required to heat up the machines**.

Step 5: Packaging

After another visual inspection is carried out in the Central Sterile Services Department, the masks are then wrapped in a single layer of sterile fleece and packaged in cartons. These cartons are then transferred to another Central Sterile Services Department, where only the next process step 6 is carried out.

Step 6: Thermal Treatment

The masks are heat-treated at 70°C for a holding time of 9 hours in recirculating air ovens (A0 value greater than 3000).

Step 7: Quality Management

Implementing a comprehensive QM system: Samples are taken from each batch, which are tested microbiologically, structurally and with regard to the filter effect. Only after all of this will the masks be approved.

Step 8: Storage

Investigations into the safety of the procedure

The team of experts at Helios carried out multi-stage comprehensive microbiological and structural investigations on masks from various established manufacturers using X-ray microtomography (micro-CT) methods and downstream tests on particle retention capacity (following the FIT test).

The process of “thermal disinfection” inactivates all vegetative microorganisms, including SARS-CoV-2 in the masks. The procedure complies with DIN 149, which requires that new masks must retain their material and shape when subjected to a continuous test at 70°C for 24 hours. In this way, the experts see no change in the masks during their thermal processing. According to Helios, endurance tests have already been initiated.

However, at the moment Helios is assuming that the masks will lose their structure or be damaged after repeated use. This is considered to be a limiting factor for multiple reprocessing. The filter function and the microbiological integrity of the processing, on the other hand, are currently considered to be less problematic.

Further information:


* Although Helios assumes that the downstream processes also ensure that tuberculosis bacteria is eliminated, microbiological detection in the laboratory requires a cultivation period of approx. six weeks. This period of time to provide evidence was not yet available and it was therefore decided to follow this approach.

** For this purpose, special temperature maintenance programs were agreed with the manufacturers of the washer-disinfectors in the air circulation procedure and programmed in the systems.

More articles:
„Hygiene in context with Corona“
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