In order to obtain market access, surgical face masks should satisfied the requirements of EN 14683:2019+AC:2019 “Medical face masks - Requirements and test methods”1. This standard defines the tests that shall be performed to assess the safety and performance requirements of surgical masks.
All the tests described in the standard shall be carried out on finished products or samples cut from finished products.
A short description of each test is reported below.
1 Bacterial filtration efficiency (BFE)
According to Annex B of EN 14683:2019, the BFE shall be tested as follows: a specimen of the mask material is clamped between a six-stage cascade impactor and an aerosol chamber. An aerosol of Staphylococcus aureus is introduced into the aerosol chamber and drawn through the mask material and the impactor under vacuum. The bacterial filtration efficiency (BFE) of the mask is given by the number of colony forming units passing through the medical face mask material expressed as a percentage of the number of colony forming units present in the challenge aerosol. When tested in accordance with Annex B, the BFE of the medical face mask shall conform to the minimum value given for the relevant Type, as described in Figure 1.
For thick and rigid masks such as rigid duckbills or cup masks the test method may not be suitable as a proper seal cannot be maintained in the cascade impactor. In these cases,another valid equivalent method shall be used to determine the BFE.
When a mask consists of two or more areas with different characteristics or different layer composition, each panel or area shall be tested individually. The lowest performing panel or area shall determine the BFE value of the complete mask.
2 Breathability
A device which measures the differential pressure required to draw air through a measured surface area at a constant air flow rate is used to measure the air exchange pressure of the medical face mask material. Test should be performed in accordance with the requirement of Annex C of EN 14683:2019 [1]. The differential pressure of the medical face mask shall conform to the value given for the relevant type, as described in Figure 1.
If the use of a respiratory protective device as face mask is required in an operating theatre and/or other medical settings, it might not fulfil the performance requirements with regard to differential pressure as defined in EN European Standard. In such case, the device should fulfil the requirement as specified in the relevant Personal Protective Equipment (PPE) standard(s).
3 Splash resistance
When tested in accordance with ISO 22609:2004 the resistance of the medical face mask to penetration of splashes of liquid shall conform to the minimum value given for Type II-R, as described in Figure 1 .
4 Microbial cleanliness (Bioburden)
When tested according to EN ISO 11737-1:2018 the bioburden of the medical mask shall be ≤ 30 CFU/g tested (see Figure 1). This standard specifies requirements and provides guidance for the enumeration and microbial characterization of the population of viable microorganisms on or in a medical device, component, raw material or packaging [2].
To determine the mask’s bioburden according to EN ISO 11737-1:2018, the producer can also refers to the procedure as described in Annex D of EN 14683:2019.
The number of masks that shall be tested is minimum 5 of the same batch/lot. In the test report, the total bioburden per individual mask shall be indicated, together with the total bioburden per gram based on the mask weight.
5 Biocompatibility
According to the definition and classification described in EN ISO 10993-1:2018, a medical face mask is a surface device with prolonged contact (more than 24 hours, less than 30 days), considering the cumulative application. The manufacturer shall complete the evaluation of the medical face mask according to EN ISO 10993-1:2018 and determine the applicable toxicology testing regime [3]. The results of testing should be documented according to the applicable parts of the EN ISO 10993 series. The test results shall be available upon request.
