Last updated: February 14, 2022


Face coverings include cloth face masks, non-medical masks, medical (surgical/procedural) masks, and N95 respirators. They are pieces of equipment that cover a user’s mouth and nose; and, are affixed to a person’s head using flexible straps that either go around the head or ears. Face coverings can be used for source control or as personal protective equipment (PPE). As an important reminder, wearing face coverings does not eliminate the need for physical distancing practices or hand hygiene.

This section focuses on the following:

  • The difference between source control and personal protective equipment
  • A summary of face covering types, and their purpose
  • An explanation on which mask is appropriate for which situations

Source Control and Community Protection

Source control means preventing or limiting the ability of the source of a contaminant from releasing it. In the case of masking, source control considers the source of the contaminant the user, with the mask being used to limit the risk of the wearer exposing others to an illness or infection. Where physical distancing cannot be maintained, it is even more important that everyone wear masks as source control. Surgical or procedure masks and respirators worn as part of PPE also work as source control. Source control works best when everyone uses it.

Personal Protective Equipment (PPE)

When the intended use of a face covering is for personal protection (protect the wearer from a contaminant) the masks used are certified to a standard such that there is a body of evidence that that particular mask will protect the user from a contaminant. To determine if a person or a particular task will require the use of face coverings as PPE, a risk assessment should be completed.  This can be done by evaluating the risk of exposure of the work while taking into account the following factors:

  • Who is involved, what processes are taking place,
  • How long individuals are together,
  • The size of the workspace; and,
  • The proximity that can be maintained between individuals

For assistance with this process, contact the Safety Office.

Some instances when Respiratory PPE is required include:

  • face to face research with humans that involve heavy breathing and exertion
  • face to face research where 2 m distance cannot be maintained
  • work that involves taking samples of blood or bodily fluids and tissues from other persons

Face covering types

The table below differentiates between the main types of masks used within the community as a method of protection from COVID-19.

Mask Type

Main Function


Cloth face mask - snug fitting, covers chin, nose, and mouth.

Cloth face mask Cloth face mask

  • Source control

Re-useable/Washable and non-regulated. Public health recommends 2 layers of breathable cotton, with the ability to add a filter of non-woven polypropylene.

Non-medical mask - snug fitting, covers chin, nose, and mouth.

surgical mask

  • Source control

Disposable, not regulated to fluid penetration. Medical and non-medical are visually indistinguishable. The difference is identifiable on the package.

Medical (surgical/procedural) mask – snug fitting, covers chin, nose, and mouth.

surgical mask

  • Source control
  • PPE for splashes of droplets, liquid or material

Disposable - regulated and standardized through the American Society of Testing and Materials (ASTM). Medical and non-medical are visually indistinguishable. The difference is identifiable on the package.

N95 Respirator – tight fit with no gaps

respirator maskrespirator mask

  • Source control
  • PPE – when fitted and the user is trained on its use for a specific hazard.

Disposable - regulated and standardized through the National Institute for Occupational Safety and Health (NIOSH). If used as PPE, a fit test is required.

Respirators with unfiltered exhalation valves

  • PPE

Not permitted

Which mask should be used?

To provide community protection in a shared indoor space, some form of face covering is required. In general, for areas such as corridors, lobbies, washrooms, elevators, classrooms, teaching laboratories and meeting rooms, a cloth/non-medical mask will reduce risk appropriately.

Public Health recommends that a non-medical mask should consist of:

  • multiple layers, including
  • at least 2 layers of tightly woven fabric, such as cotton and
  • a third, middle layer of filter-type fabric, such as non-woven polypropylene
  • materials that are breathable

Medical/Surgical masks can be used to protect the wearer and others against larger droplets or sprays by creating a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment.  Their use should be based upon a risk assessment. The University provides ASTM Level 2 masks which are required to be worn by employees where physical distancing (2m) cannot be maintained.

Some notes on medical/surgical masks:

  • The American Society of Testing and Materials (ASTM) have testing protocols that examine how medical masks perform for filtration, breathability, fire resistance, fluid resistance and material quality.
  • Medical/surgical masks are used for source control and to protect the user from splashes of liquids and materials that may arise from a procedure.  Although they have a rated filtration efficiency, they are not considered to provide the wearer a reliable level of protection from others because they do not make a tight seal against the face.
  • Medical masks are visually indistinguishable from non-medical disposable masks.  To distinguish between medical and non-medical disposable masks you must review the packaging of the mask.

Some notes on N95 respirators:

  • N95’s are reserved for high-risk activities or applications. High risk refers to working with infected or suspected infectious individuals, or working closely with individuals who cannot wear a mask. In this case, the N95 respirator would be considered PPE and would require selection, training and fit testing under the University’s Respirator Protection Program.
  • If an N95 is not required as a result of a risk assessment and being used as source control for community protection, a fit test is not required.
  • Individuals who use N95’s as source protection should ensure that they fit properly and create a good seal to the face. To perform a seal check for an N95 face covering:
    • Put on the mask.
    • Place both hands over the mask and breathe in and out.
    • If you have a good seal, the facepiece should collapse slightly when you inhale. As you exhale, you should not feel air leaking out.
    • If you have air leaks, check that nothing is obstructing (blocking) the sealing surface, adjust the noise piece or straps, and repeat the user seal check.

PPE Face shields and Goggles:

Face shields are plastic coverings that wrap around the face.  They mainly provide protection to the eyes and face of the wearer from respiratory droplets and sprays and are worn with respiratory protection. 

Goggles are plastic devices worn on the head to protect the eyes from respiratory droplets and sprays.  There are many different styles and types, but the most effective wrap around the sides of the face and cover the eyes from all angles.

Guidance on the use of face shields and goggles is below:

  • Wearers should wash their hands before and after removing and avoid touching their eyes, nose and mouth when removing it.
  • Reusable face shields and goggles should be cleaned and disinfected after each use according to manufacturer instructions or by following CDC face shield cleaning instructions.
  • Face shields or goggles should not be used as a substitute for a face covering, and are considered barrier protection against droplet spread.
  • Face shields must be individually provided

Face shields or goggles should be worn in conjunction with a face mask when work in close proximity (< 2m) of other people for prolonged periods of time (> 15 min.) is expected, or if working in close proximity to someone who is not wearing a face covering.


Exemptions include the following:

  • People who are unable to wear a mask due to a medical condition or disability
  • Children under the age of 2
  • When communicating with a person who is hearing impaired and the ability to see the mouth is essential for communication
  • When wearing a face covering would create a risk to the wearer related to their work, as determined by workplace safety guidelines

If you need an exemption for a medical condition or disability, you must provide appropriate documentation to the University. Please review the Face Covering Exemption Request Form and submit the completed form to AccessAbility Services (students) or Occupational Health (employees) to develop an accommodation plan.

Accommodations may include remote participation (academics) or alternate arrangements (employees), which will be reviewed on a case-by-case basis.