Face mask is widely used as personal protective equipment to protect user from airborne particles as well as liquid contaminant. Numerous test methods have been developed to classify the performance of face mask, which includes of the material performance on particle filtration efficiency, bacterial filtration efficiency,  water repellent/absorption capability, flammability, differential pressure etc for the compliance of ASTM F2100 and EN 14683 specification of face mask.

ASTM F2100 Specification

Parameter	Method	Sample Size	Turn Around Day	Level I	Level II	Level III
Bacterial Filtration Efficiency (BFE), %	ASTM F2101	5	5 days	≥ 95	≥ 98	≥ 98
Differential Pressure, mm H2O/cm2	MIL-M-36954C	5	5 days	> 4	≥ 98	≥ 98
Resistance to penetration by synthetic blood (mm Hg)	ASTM F1862-07	32	5 days	80	120	160
Flame Spread	16 CFR Part 1610	14	5 days	Class 1	Class 1	Class 1
Particle Filtration Efficiency (PFE), %	ASTM F2299	5	10 days	≥ 95	≥ 98	≥ 98

 

EN 14683:2019 + AC:2019

Parameter	Method	Sample Size	Turn Around Day	Level I	Level II	Level IIR
Bacterial Filtration Efficiency (BFE), %	EN14683 (Annex B)	5	5 days	≥ 95	≥ 98	≥ 98
Differential Pressure, Pa/cm2	EN14683 (Annex C)	5	5 days	> 29.4	> 29.4	> 49.0
Resistance to penetration by synthetic blood (kPa)	ISO22096:2004	32	5 days	-	-	≥ 160
Microbial Cleanliness (cfu/g)	ISO 11737-1 : 2006	5	5 days	≤ 30	≤ 30	≤ 30
Dermal Sensitization	ISO 10993-10	20	45-60 days	-	-	-
Skin Irritation	ISO 10993-10	20	45-60 days	-	-	-
Cytotoxicity	ISO 10993-5	20	45-60 days	-	-	-

 

Bacterial Filtration Efficiency

The Bacterial Filtration Efficiency (BFE) test is performed on filtration materials and devices that are designed to provide protection against biological aerosols, such as face masks, surgical gowns, caps, and air filters. The Bacterial Filtration Efficiency test determines the filtration efficiency by comparing the bacterial control counts to test article effluent counts. The test is conducted using Staphylococcus aureus as the challenge organism.

 

Flammability

The Flammability test procedure evaluates the flammability of medical textiles including face masks, surgical gowns, and drapes.The Flammability test determines the time of flame spread for the given material. All fabrics of natural or regenerated cellulose, as well as certain types of finished and unfinished fabrics made from other natural or synthetic fibers, are combustible. Some combustible fabrics are potentially dangerous to the wearer because of the speed and intensity of flame with which these fabrics burn and their ease of ignition.

 

Differential Pressure (Breathability)

The Delta P test is performed to determine the breathability of masks by measuring the differential air pressure on either side of the test article using a manometer, at a constant flow rate of 8 L/min.

 

Water Absorption

The outer-most layer should be water-resistant (Hydrophobic) , and the middle layer, which is used to trap bacteria, should not be too porous. The innermost layer has to be able to absorb moisture such as saliva, mucus and sneeze droplets.

 

Resistance to Penetration by Synthetic Blood (mm Hg)

This test method offers a procedure for evaluating medical face mask resistance to synthetic blood penetration that is useful in establishing claims for penetration resistance performance of medical face masks and ranking their performance.

 

Particle Filtration Efficiency (PFE)

The Particle Filtration Efficiency (PFE) test evaluates the inert particle retention or filtration efficiency of face masks. It is measured by using non-living, or non-viable particles at submicron levels. The testing is conducted at a single particle size and can be tested at 0.1µm, 0.3µm, 0.5µm and 1.0µm which complying to different specification (ASTM F2100, NIOSH).

 

Cytotoxicity Test – ISO 10993-5

Cytotoxicity is a rapid and standardized test that is very sensitive to evaluate a significant quantity of harmful extractables (leachable substances) present in a device material and the effect they may have on cellular components.

 

Dermal Sensitization Test – ISO 10993-10

Sensitization or hypersensitivity tests look for adverse reactions in animals by exposing the animal to the material or by using extracts from the device or materials and injecting and/or topically applying them to the animal. Sensitization reactions are graded according to scores for erythematous and oedematous lesions on the skin.

 

Skin Irritation Test – ISO 10993-10

This test evaluates the reaction to a single, repeated or continual exposure from device materials that have the potential to produce skin irritation. The test does not involve immunological mechanism. The Intracutaneous Irritation test uses extracts of a test material and blank injected intradermally. Injection sites are scored for erythema and oedema. This procedure is recommended for devices that will have externally communicating or internal contact with the body or body fluids. It can reliably detect the potential for local irritation due to chemicals that may be extracted from a device material.