Face masks are incorporated into public health measures as part of the response to the COVID-19 pandemic. It provides a barrier against airborne pathogens like viruses and bacteria to the user. However, not all face masks offer the same level of protection. Their performances must be tested with scientifically sound testing methods. Overall face mask evaluation guarantees that masks are safe and protective for use in medical, industrial, or other public environments. Here we provide information on the critical attributes encompassed in face mask evaluation, such as testing parameters, filtration efficiency, antimicrobial properties, comfort and regulatory compliance.

Understanding key testing parameters

Face mask testing entails examining several key parameters directly impacting the effectiveness of masks in protecting their users. Some of these include:

• Filtration efficiency to determine the effectiveness of a mask in filtering bacteria, viruses, and particles passing in the air.
• Fluid resistance to test a mask’s capability to block liquid penetration, such as droplets containing pathogens.
• The masks are tested for their antimicrobial properties where the antimicrobial agents are applied to some masks with the aim of decreasing the amount of harmful microorganisms on them.
• Breathability test is to determine whether the masks allows for adequate airflow while maintaining protection.
• Comfort for extended use periods, especially in healthcare and industrial applications.

EN 14683 – This European standard is set to specify the requirements, testing procedures, construction and design specifications of medical face masks.

These face mask evaluation parameters help manufacturers and regulatory bodies determine whether a mask provides sufficient protection and comfort for its intended application.

Filtration Efficiency Testing (BFE, PFE)

Filtration efficiency is one of the most critical parameters in face mask evaluation. It is used in testing or measuring how effectively a face mask can filter out contaminants, such as bacteria and particles, from the air.

Bacterial Filtration Efficiency (BFE)

BFE measures the filtering efficiency using the challenge organism Staphylococcus aureus, which is usually applied during laboratory testing. Bacterial aerosol will pass through the material and the number of bacteria that penetrate the material is measured. Masks whose BFE is greater than 95% are said to be capable of filtering airborne bacteria.

ASTM F2101 is the standard test method used to assess bacterial filtration efficiency (BFE) of the materials used in making medical face masks. This is a test aimed at determining whether or not the material under test could resist penetration by bacteria, an important determinant for deciding the quality and performance of medical masks.

Particle Filtration Efficiency (PFE)

PFE tests the mask for its filtration capacities of fine particles, including bacteria and organisms smaller than bacteria. As the viruses and most other microcontaminants are much smaller than bacteria, it becomes pertinent that PFE tests a mask’s performance against influenza virus and SARS-CoV-2. The higher PFE also gives a better protection performance by a mask against pathogens.

Face mask evaluation includes filtration efficiency testing which is crucial in healthcare institutions where the risk of airborne pathogens is high. It ensures that masks provide enough protection for both health personnel and patients.

Fluid resistance and barrier performance testing

• Fluid resistance testing evaluates the effectiveness of a mask in protecting against the passage of fluid-borne substances such as respiratory droplets, blood, or other body fluids. Face mask evaluation includes numerous steps especially since they are often used in application environments where the wearer may be exposed to aerosols or splashes of fluids.
• Synthetic blood penetration tests are performed to simulate conditions which arise in the real field when healthcare workers deal with various medical procedures. In this test, synthetic blood is projected toward the mask at various pressure levels to evaluate how effectively the mask will resist penetration.

Antimicrobial, antiviral, and antifungal testing

With the growing demand for greater protection, face mask evaluation involves testing against antimicrobial, antiviral and antifungal agents. These treatments often lower the growth or existence of microorganisms on the face mask’s surface for extra protection against contaminants.

• Antimicrobial testing assesses how well the mask works not to allow bacteria or viruses to grow on it. This test, instead, is particularly useful for masks intended to be used in long-term care settings or with high-contact environments where masks become contaminated over time.
• Antiviral and antifungal testing will determine if the mask is working effectively in inhibiting the survival of viruses and fungi attaching to its surface. Examples are masks that would experience high levels of mold or fungal spores, such as those used over areas that are prone to the presence of such organisms.

Face mask evaluation for these properties ensures they are safe for extended use and provide ongoing protection, particularly in settings where masks are worn for long periods or where there is a high risk of contamination.

Breathability and comfort assessment

Although the face mask evaluation details filtration efficiency and resistance of fluid as key parameters, breathability and comfort become critical factors especially when masks have to be worn for a significant time. It is unlikely that an unfriendly mask or a mask that cannot give access to easy breathing would be used properly, thus working against its protective value.

• Breathability is determined through a differential pressure (Delta P) test, measuring how easy it is for air to pass through the mask. The mask with the smallest differential pressure would allow easier breathing and good filtration. To avoid discomfort and fatigue to the wearer, effective airflow is essential.
• Comfort testing encompasses all aspects such as the fit of the mask, how it would feel with the texture of the material and whether or not it would irritate the skin of a user. A mask that is too tight, irritating, or ill-fitting may cause discomfort, resulting in either improper use or premature removal.

ASTM F2100 is a standard that describes the performance requirements for medical face mask materials that should be used in manufacturing. The categories of requirements are bacterial filtration efficiency, differential pressure or breathability, fluid resistance and flammability.

Regulatory compliance and industry standards

To be sold and distributed in the market, face masks must pass and meet all regulatory requirements. Therefore, by virtue of this regulation, masks should suffice in giving protection and the materials used to ensure safety in human use.

Compliance with set face mask safety standards assures safety of a product but also accords customer confidence. Only face masks that have passed standard tests appear certified for protection, hence becoming reliable for use by the public and healthcare professionals.

Decision-making and quality assurance

Quality assurance in face mask production ensures that the products manufactured consistently are in conformity with the set standards on their safety and efficacy. Face mask evaluation ensures quality to the manufacturer by testing every batch at different times in the production process, thus ensuring that the masks from each batch meet the standards.

• Batch testing of the masks involves random sampling of masks from all batches produced then tested to see if they pass the stringent set criteria regarding safety and performance.
• Supply chain monitoring ensures that all materials used in making mask are safe and of high quality. For example, the requirement of filter materials in masks must meet PFE requirements to ensure that the produced masks are effective.

Practical implementation and future adaptation

The face mask sector changes with the development of new emerging technologies. New materials and designs are being manufactured to ensure improved protection, comfort and sustainability.

• Self-disinfecting masks

 Developing self-cleaning masks that contain materials to kill or inactivate pathogens on touch is under process, ensuring that such masks do not need to be replaced or cleaned to continuously protect the wearer.

• Reusable masks 

In response to the growing concern for sustainability, manufacturers focus on developing effective reusable masks that can be worn multiple times without a reduction in protection after multiple washing cycles.

In the future, face masks may also incorporate smart technology, they might have sensors that can detect the quality of air or even remind the mask wearer it is time to replace the mask. Such innovations highlight why there has been a necessity to continually assess and adapt to changing demands in health care.

Conclusion

A careful face mask evaluation will lead to maximum protection for wide-ranging applications. Common performance testing parameters include filtration efficiency, fluid resistance, antimicrobial properties and comfort. Altogether, these are important factors in assessing the overall effectiveness of a face mask. 

For manufacturers interested in validating face mask performance, Microbe Investigations Switzerland(MIS) offers comprehensive face mask testing and validation services. Contact MIS today to ensure your masks meet the highest standards of safety, protection and comfort.