Respirator - Respirator Fit Testing

Respirator fit testing ensures that the respirator seals effectively against the user's face and that the respirator provides the expected level of protection. Fit testing verifies that the respirator's make, model, and size are providing the user with appropriate protection. Workers should be fit tested before using a respirator at work. 

All respirators that rely on a seal to perform the specified capabilities, which are usually tight-fitting, require a fit test. These respirators can include, but are not limited to:

• Disposable respirator (e.g., N95) 
• Half-face respirator
• Full-face respirator
• Self-contained breathing apparatus 

Canadian Standards Association Standard Z94.4-18 (R2023) Selection, Use, and Care of Respirators requires workers using a respirator to be fit tested. A fit tester must be competent in the applicable fit test method, whether that is qualitative or quantitative fit testing and be able to verify the user's ability to obtain an effective seal. The fit tester must be able to confirm the user's eligibility for wearing a mask, conduct sensitivity screening, interpret screening results, and document findings. For quantitative fit testing, the fit tester must also be able to calibrate the machine and recognize when the machine needs to be calibrated.  

Fit test training programs are available; however, there is no specific formal training for fit testing required in occupational health and safety legislation in Canada. Fit testers must be competent, meaning they have the knowledge, training, and experience to conduct fit testing. The manufacturer of fit testing equipment may have guidelines and manufacturer training on the use of their equipment.

The fit tester shall be competent in the applicable fit test methods and be able to verify a user’s ability to obtain an effective respirator seal, comfort, and fit for a tight-fitting respirator. The fit tester shall also manage the overall fit testing process, including the transition between sensitivity screening and fit testing where applicable, interpret test results, and document user, respirator, and instrument performance.  

Before conducting fit testing:

• Medical surveillance must be completed before using a respirator, ensuring the user is physically capable of wearing a respirator safely and performing job functions without risk to their health. Check your jurisdiction's requirements for medical surveillance.
• Workers must be clean-shaven and free from hair that may interfere with the seal of the respirator to the skin of the face or neck. CSA Standard Z94.4-18 (R2023) Selection, Use, and Care of Respirators recommends shaving 12 to 24 hours before wearing respirators. Hair growth rate varies greatly from one individual to another.
• The worker should wear a respirator under the conditions for which a fit test was obtained.
  • For example, if the worker plans to wear dentures while wearing a respirator, the dentures should be worn during the fit test. 

A qualitative fit test (QLFT) verifies if the respirator fits the user's face correctly by using a fit testing agent. The user is asked to determine if they can taste or smell the test agent. 

Pros:

• Inexpensive test to conduct
• No specialized equipment is required
• Tests can be conducted anywhere

Cons:

• It is a subjective test as it relies on the user's senses
• Cannot be used to test full-face respirators

The testing agent may be accompanied by a safety data sheet (SDS). The SDS will inform users about the product’s hazards, safe handling, and emergency measures, as well as advise on the product’s recommended use and restrictions. It is important to read and understand the SDS before using the product.

A quantitative fit test (QNFT) uses a machine to measure the efficacy of a respirator's seal to the user's face. The machine measures the particles that leak through the mask as the user performs different activities, such as moving their head and reading out loud. 

Pros:

• Accurate and objective test
• Can be used for any tight-fitting respirator, including full-face respirators
• Does not rely on the individual's sense of smell or taste

Cons:

• Requires specialized equipment and the test administrator to be trained on the equipment
• Test is more expensive  
• The test usually requires a controlled setting 

It is a good practice for employers to keep a record of the fit testing they have conducted. Workers should also keep a record of their fit testing. A common practice is for the individual being fit tested to be provided with a fit test card. Fit test records should include:

• The date of the fit test
• The name of the person being fit tested
• Name of the person conducting the fit test
• The specific make, model and size of the respirator used during the testing
• The type of fit test conducted: qualitative or quantitative 
  • If qualitative, record the fit testing agent used
  • If quantitative, the technology used to conduct the test
• Pass or fail criteria
• List of additional personal protective equipment (PPE) worn during the fit test
• Restrictions as they relate to facial features, facial hair, facial jewelry, dentures, eyewear or cosmetics
• Fitting difficulties  
• Workers' competency in inspecting respirators, putting on a respirator and performing a seal check
• Unsuccessful fit tests, including the cause for failure
• Fit test machine make, model, maintenance and calibration
• Result of comfort assessment

Fit testing should be repeated every two years. Some circumstances would require a fit test to be repeated sooner, such as:

• Any alteration to the face shape
• Significant fluctuation in weight
• Dental work which will affect facial structure
• Facial surgery  
• Switching to a different size or make of respirator
• If the use of a respirator causes significant discomfort  
• Change in personal protective equipment (PPE) use, which can affect the respirator 

If a mask does not fit properly, the seal is not performing to its intended filtration capabilities. The wearer may be exposed to products that can be hazardous.

Below is a table for guidance purposes, listing legislation and a general summary of respirator user screening and medical assessments.  NOTE that other requirements may be listed in other sections, regulations, Codes, or Acts that are not listed in this table. For more details, consult the legislation directly.

Always consult the legislation that applies in your situation and with your jurisdiction for complete information. 

Note:  Certain CSA Group standards are available for online viewing. To access these, you must first create an account with “CSA Communities”. Go to: https://community.csagroup.org/login.jspa?referer=%252Findex.jspa

Once you are logged in, click on the text below the “OHS Standards / View Access” graphic. Click on the jurisdiction of your choice to see the CSA Standards as referenced in that legislation. Standards may also be purchased from CSA Group: https://store.csagroup.org/