Successful establishment and evaluation of a reprocessing concept via steam at 105 °C for FFP masks in hospitals in case of logistic shortages.

Filtering face piece (FFP) masks according to EN 149 Respiratory protective devices - Filtering half masks to protect against particles - Requirements, testing, marking are essential components of personal protective equipment against biological agents from an occupational health and hospital hygiene perspective. Therefore, shortages due to increased demand or supply bottlenecks can lead to staff threats due to the risk of infection. To determine whether FFP masks could be made reusable in a hospital setting, a thermal reprocessing concept (steam at 105 °C with a holding phase of 10 min) was evaluated in a bed reprocessing chamber. The results indicate that it is logistically possible to establish a reprocessing concept. Of 267 reprocessed masks, 48 were rejected by inspection because of defect strapping, trapped hair, misfolding, and missing lot number or deformation, and 22 masks were rejected by bacteriological examination because of contamination > 10 CFU of total bacteria per 25 cm² or the presence of Staphylococcus aureus. Two selected mask models maintained the expected mask performance equivalent to the FFP2 standard after reprocessing. Thermal reprocessing resulted in a virucidal effect. The results show that reprocessing of FFP masks in hospitals is possible. However, the success of reprocessing depends on the type of mask used. This study identified a suitable mask type for which the reported method is bactericidal and virucidal without impairing mask performance. The reported method required the use of a stationary hospital bed reprocessing chamber (sanitizing washer), so it cannot be used everywhere. Other methods and procedures should be tested to be independent of a bed reprocessing chamber and therefore may be more mobile and flexible.