If you want to understand the ASTM standards for medical masks, you must familiarize yourself with ASTM F2100-21.

What is the ASTM Standard for Medical Masks?

ASTM standards are vital to the medical mask industry because they provide production guidelines to ensure masks effectively protect people from infection. The most critical standard is ASTM F2100, which specifies performance requirements for three different levels of masks: Level 1, Level 2, and Level 3. To be recognized as a medical mask, a product must meet specific filtration and fluid barrier requirements.

• Level 3 masks provide the highest grade of protection, requiring a Bacterial Filtration Efficiency (BFE) of $\ge 98\%$ and fluid resistance of $160 \text{ mmHg}$.

• ISO 10993-1 is another essential standard providing guidelines for the safety of materials in contact with human skin.

For any reputable medical equipment manufacturer, strictly following these ppe standards is an absolute, non-negotiable bottom line. It is simple: only masks that successfully pass these rigorous ASTM tests can be safely and legally classified as true medical devices. This strict classification is what ultimately guarantees that frontline healthcare workers get the reliable protection they need when it matters most.

Applications of ASTM F2100-21

Standard Specification for Performance of Materials Used in Medical Face Masks

The ASTM F2100 standard is widely used in the United States and other countries as the primary guideline for evaluating the performance of medical masks, including those used against the SARS-CoV-2 virus. It offers three levels of protection based on intended use:

ASTM Protection Level	Fluid Resistance	BFE / PFE Filtration	Ideal Medical Scenarios
Level 1	80 mmHg	More than 95%	Low-risk (e.g., basic exams, visitor use)
Level 2	120 mmHg	More than 98%	Moderate-risk (e.g., dental procedures)
Level 3	160 mmHg	More than 98%	High-risk (e.g., surgeries with heavy fluid splash)

When should you use an ASTM Level 1 mask? (Scenarios)

ASTM Level 1 masks are generally used for low-risk situations and tasks, such as visiting a doctor or using public transportation. They are designed to provide basic protection against respiratory droplets and large particles. Made from lightweight, breathable materials, they feature ear loops or ties for security. While healthy individuals can wear them to prevent spreading infection to others, they are not designed for high-risk environments and should not replace measures like social distancing and handwashing.

When should you use an ASTM Level 2 mask? (Scenarios)

ASTM Level 2 masks are used for moderate-risk situations, such as dental procedures or clinical exams. They are made of thicker, more durable materials than Level 1 masks and provide higher protection. They block at least $98\%$ of very small particles ($0.1 \mu m$) and may have even higher efficiency for larger particles.

When should you use an ASTM Level 3 mask? (Scenarios)

ASTM Level 3 masks are intended for high-risk situations, such as during surgery or when exposure to body fluids or blood is highly likely. These masks use the thickest and strongest materials to provide the maximum level of protection. They block at least $98\%$ of sub-micron particles ($0.1 \mu m$) and up to $99\%$ of larger particles. They may have higher breathing resistance and are used in surgeries where significant aerosols are generated.

Additional Information Regarding ASTM Standards

To achieve certification for a specific performance level, masks must undergo a comprehensive battery of tests designed to quantify their efficacy in protecting the wearer against various airborne contaminants. Among these, the most critical is the Filtration Efficiency test, which evaluates the mask’s capacity to intercept submicron particles from the air. Generally, a mask demonstrating a filtration efficiency of 95% or higher is classified as “medical-grade.”

While the ASTM F2100 standard is primarily engineered for medical face masks, its framework is also applicable to other categories of Personal Protective Equipment (PPE), such as respirators.

In a broader sense, any PPE intended to provide respiratory protection—including defense against dust, smoke, or chemical vapors—should, at a minimum, satisfy the baseline filtration efficiency requirements established within these standardized protocols.

FDA Regulations and Policies Regarding Face Masks

The U.S. Food and Drug Administration (FDA) regulates face masks, medical masks, and surgical masks, classifying them as Class II medical devices. Face masks are designed to protect the wearer from airborne particulates, bacteria, and viruses. Medical masks are intended to protect the wearer from body fluids, including blood, saliva, and mucus. Surgical masks are specifically designed to protect the wearer from surgical instruments and other items that may be contaminated with blood or body fluids.

When hospital administrators evaluate what ppe required means for their specific wards, they rely heavily on how the FDA distinguishes between everyday face masks (like basic cloth or dust masks) and true clinical surgical masks. The key difference? Only true surgical masks are subjected to strict fluid resistance testing, proving they can actually block the dangerous splash of bodily fluids.

How Do ASTM Standards Regulate Mask Performance?

ASTM evaluates mask performance by measuring two primary factors: filtration efficiency and breathability. Filtration efficiency refers to the percentage of particulate matter successfully filtered out by the mask. Breathability refers to the volume of air that can pass through the mask material.

• Filtration Efficiency Testing: Particulates of a standard size are used, and the mask is secured onto a mannequin head. The mannequin is then placed within an aerosol environment to measure the percentage of filtered particles.

• Breathability Testing: A mannequin head is placed inside a sealed chamber, and air is forced through the mask. The volume of air that successfully passes through is then measured.

ASTM has established specific standards for different types of masks. These standards dictate the acceptable materials for mask manufacturing, performance requirements, and precise testing methodologies.

 

Are Surgical Masks Considered Medical Devices?

The classification of a surgical mask depends on its design, intended use, and method of wear. In accordance with the U.S. Code of Federal Regulations 21 CFR 878.4040, surgical masks are classified as Class II medical devices. They are required to meet specific standards for filtration, breathability, and resistance to splashes and sprays. Both the testing procedures and the materials used in surgical masks must comply with ASTM International standards.

Medical masks can be manufactured from a variety of materials, including cotton, polyester, polypropylene, or other synthetic fibers. Material selection is driven by manufacturer specifications or the specific functional requirements of the mask.

Distinctions Between ASTM Level 1, 2, and 3 Masks

(Note: For the European Union market, please refer to corresponding literature on EN 14683.) Let us examine each specific testing domain and its associated terminology in detail.

 

ASTM Standards and Terminology

1. BFE (Bacterial Filtration Efficiency)

Bacterial Filtration Efficiency (BFE) is a metric used to evaluate a medical mask’s ability to filter out bacteria when exposed to a bacteria-laden aerosol. ASTM recommends utilizing droplets containing Staphylococcus aureus (with an average particle size of 0.6–0.8 microns) for this test. The minimum filtration efficiency requirement for medical/surgical masks is 95%. High- and moderate-protection masks are required to achieve a BFE of at least 98%. While some manufacturers employ the modified Greene & Vesley method to determine BFE values, ASTM does not recommend this method for product comparison or conformity assessment.

2. Particulate Filtration Efficiency (PFE)

Particulate Filtration Efficiency (PFE) measures a medical mask’s capacity to filter submicron particles, serving as a critical indicator for predicting viral filtration efficacy. A higher PFE value signifies superior filtration performance. The ASTM F2100 standard recommends a particle size range of 0.1 to 5 microns for testing.

When comparing test results, it is crucial to observe the specific particle size used, as larger particles can skew PFE ratings.

3. Fluid Resistance

Fluid resistance denotes a surgical mask’s ability to minimize the transfer of liquid from the outer layer to the inner layer upon exposure to splashes or sprays. ASTM recommends testing fluid resistance using synthetic blood at pressures of 80, 120, and 160 mmHg. This evaluates the mask’s capability to mitigate fluid penetration during a splash or spray event. These pressure values correlate with human blood pressure metrics:

• 80 mmHg = Venous pressure (Level 1)

• 120 mmHg = Arterial pressure (Level 2)

• 160 mmHg = Correlates with high pressures potentially encountered during trauma or high-pressure irrigation procedures, such as orthopedic surgeries (Level 3)

 

4. Differential Pressure (ΔP)

Differential pressure (Delta P) is an objective measure of airflow resistance and breathability. The Delta P value is expressed in millimeters of water per square centimeter (mm H2O/cm²). A lower Delta P value indicates better mask breathability. Current ASTM standards require a Delta P of less than 6.0 for low-barrier masks.

 

5. Flame Spread

Given that hospital environments frequently contain sources of heat, oxygen, and fuel, ASTM standards mandate flame spread testing. All medical masks must be able to withstand exposure to a burning flame for a minimum of three seconds.

 

6. ISO Certification

In addition to passing the aforementioned tests, all medical masks must undergo skin sensitivity and cytotoxicity testing (ISO 10993-5, -10) to ensure safety, as the manufacturing materials come into direct and prolonged contact with human skin.

 

ASTM Protection Levels and Intended Use

• Level 1 (Low Protection): Fluid resistance of 80 mmHg. Provides light/minimum BFE and PFE protection. Suitable for general procedures and respiratory examinations. Offers greater breathability compared to higher-protection masks and is designed to resist splashes or sprays at venous pressure.

• Level 2 (Moderate Protection): Fluid resistance of 120 mmHg. Provides high BFE and PFE protection. Designed to resist splashes or sprays at arterial pressure.

• Level 3 (High Protection): Fluid resistance of 160 mmHg. Provides high BFE and PFE protection. Offers the maximum level of fluid resistance, specifically designed to withstand splashes or sprays during high-risk procedures such as orthopedic surgeries or trauma care.

 

References:

• ASTM F2100 – Standard Specification for Performance of Materials Used in Medical Face Masks. (n.d.). ASTM International. Retrieved August 18, 2021, from https://www.astm.org/Standards/F2100.htm

• Bacterial and Viral Filtration Efficiency (BFE/VFE) Tests. (n.d.). Nelson Labs. Retrieved August 18, 2021, from https://www.nelsonlabs.com/testing/bacterial-viral-filtration-efficiency-bfe-vfe/

• Particle Filtration Efficiency (PFE) Testing | Nelson Labs. (n.d.). Nelson Labs. Retrieved August 18, 2021, from https://www.nelsonlabs.com/testing/particle-filtration-efficiency-pfe/