Written and maintained by CASRAI Editorial Board
Last updated
This page describes products and general use; it is not medical advice.
What is a face mask?
The FDA defines a face mask as “a product that covers the wearer’s nose and mouth.” It is used as source control and, in the FDA’s wording, face masks “are not personal protective equipment.” A face mask may or may not meet filtration and fluid barrier levels, and the FDA says it is not a substitute for an N95 respirator (FDA, page current as of 10/21/2024, checked 2026-10-30).
In everyday use the word covers four product classes that regulators treat differently: face masks without a performance claim, barrier face coverings, surgical masks and N95 respirators.
Types of face masks
| Type | Regulatory status (as stated by the FDA) | Fit | Filtration and fluid |
|---|---|---|---|
| Face mask | Covers nose and mouth; source control; not PPE | Not specified as sealing | May or may not meet filtration and fluid barrier levels |
| Barrier face covering | References ASTM F3502-21 | Covers at least nose and mouth | Should meet the particulate filtration efficiency, airflow resistance and leakage assessment recommendations; gives “a degree of particulate filtration” |
| Surgical mask | Regulated under 21 CFR 878.4040; Class II (special controls) | Loose-fitting; edges not designed to form a seal | Physical barrier; does not filter or block very small airborne particles; made in different thicknesses with different ability to protect from contact with liquids |
| N95 respirator | Most are regulated by NIOSH; surgical N95s are Class II under 21 CFR 878.4040 | Very close facial fit; edges form a seal around nose and mouth | Very efficient filtration of airborne particles |
Sources for the table: the FDA page and 21 CFR 878.4040 (Cornell LII), both checked 2026-10-30; links are in the Sources section.
Surgical masks
The FDA describes a surgical mask as “a loose-fitting, disposable device that creates a physical barrier between the mouth and nose” and the environment. Under 21 CFR 878.4040 surgical apparel is intended to be worn by operating room personnel during surgical procedures to protect the patient and staff from transfer of microorganisms, body fluids and particulate material. See what a surgical mask is.
N95 respirators
An N95 is “a respiratory protective device designed to achieve a very close facial fit.” Under 21 CFR 878.4040(b)(1) a surgical N95 is exempt from premarket notification only when its user-contact components are biocompatible, flammability is characterized, it resists penetration by fluids such as blood, and it is NIOSH approved; it is not exempt if intended to prevent specific diseases or infections. See what an N95 respirator is and NIOSH-approved N95 masks.
Barrier face coverings
The FDA describes a barrier face covering as a product worn on the face covering at least the wearer’s nose and mouth, and points to ASTM F3502-21 for its performance recommendations.
Related equipment
A face shield is a different product from the masks above. Respirators for gases and vapors are covered in gas mask types.
Who uses them
Surgical apparel, including surgical masks, is intended to be worn by operating room personnel (21 CFR 878.4040(a)). Face masks and barrier face coverings are worn to cover the nose and mouth as source control.
How to choose a face mask
The FDA’s own distinctions are the criteria this page relies on:
- If the goal is source control (covering the wearer’s nose and mouth), a face mask or barrier face covering fits that description.
- For a physical barrier against liquids, the FDA notes surgical masks are made in different thicknesses with different ability to protect from contact with liquids, so the product’s stated fluid-barrier level matters.
- A very close facial fit with efficient filtration of airborne particles is the N95 description; the FDA states face masks are not a substitute for N95s.
Follow your facility’s infection-control policy and the manufacturer’s instructions for use.
How to put on and wear a face mask
By definition a face mask covers the wearer’s nose and mouth, so both must be covered while it is worn. A surgical mask is loose-fitting and its edges are not designed to seal. An N95 is designed for a very close facial fit with edges that seal around the nose and mouth (FDA); the donning steps are in how to wear an N95 mask.
Common mistakes
- Treating a face mask or surgical mask as if it were an N95. The FDA says face masks are not a substitute for N95s and that surgical masks do not filter or block very small particles in the air.
- Treating a mask as PPE when it is sold only as source control. The FDA says face masks are not personal protective equipment.
- Expecting a loose-fitting surgical mask to seal: the FDA says its edges are not designed to form a seal around the nose and mouth.
FAQ
What is a face mask?
A product that covers the wearer’s nose and mouth, used as source control and not classed as PPE (FDA, checked 2026-10-30).
How do I choose a face mask?
Match the product class to the need: source control (face mask or barrier face covering), a liquid barrier (surgical mask, whose fluid protection varies) or a sealed respirator (N95). See the table above.
How do I put on a face mask?
Cover the nose and mouth. For an N95, follow the steps in how to wear an N95 mask.
How do I wear a face mask?
Keep it covering the nose and mouth for as long as it is worn, and follow the manufacturer’s instructions for use for the specific product.
Sources
- FDA, N95 Respirators, Surgical Masks, Face Masks, and Barrier Face Coverings, current as of 10/21/2024, checked 2026-10-30.
- 21 CFR 878.4040, Surgical apparel (Cornell LII), checked 2026-10-30.
Related product category: elastic bandages.
