A respirator fit test checks that a tight-fitting respirator seals to a specific worker's face. There are two methods: a qualitative fit test relies on the wearer tasting or smelling a test agent, and a quantitative fit test uses a machine to measure leakage. Qualitative testing is the practical choice for N95s and half-mask respirators in most programs; quantitative testing is needed for full-face respirators and wherever you want an objective number. This guide compares the two and shows what ERE carries for the qualitative method.
In this guide
- Why is a respirator fit test required?
- How does a qualitative fit test work?
- How does a quantitative fit test work?
- Qualitative vs quantitative: which should you choose?
- What does a qualitative fit test kit include?
- What has to be in place before the test?
- How often should a respirator fit test be repeated?
- Frequently Asked Questions
Why Is a Respirator Fit Test Required?
A fit test confirms that the make, model and size of respirator you issue actually seals on the person wearing it. A tight-fitting respirator that leaks around the face does not deliver the protection printed on its filter, however good the filter is.
The Canadian Centre for Occupational Health and Safety (CCOHS) notes in its respirator fit testing fact sheet that the CSA standard Z94.4-18 (R2023), Selection, Use, and Care of Respirators, requires workers using a respirator to be fit tested. It covers every respirator that relies on a seal, including disposable respirators such as N95s, half-face and full-face respirators and self-contained breathing apparatus. Provincial and federal regulations point to Z94.4, and the edition each one cites differs, so check your own jurisdiction. If you are still choosing the respirator itself, start with our half-mask respirator guide.
How Does a Qualitative Fit Test Work?
The wearer puts on the respirator and breathes a test agent, and the tester asks whether they can taste or smell it. If they can, the respirator is leaking and the test is failed; if they cannot, it passes. CCOHS describes the method as a qualitative fit test (QLFT).
Most workplace programs use a taste agent, and there are two common ones:
- Sweet (saccharin): the agent in the 3M FT-10 kit.
- Bitter (Bitrex): the agent in the 3M FT-30 kit, with FT-31 used for the sensitivity check and FT-32 for the fit test itself.
Before the fit test, the tester runs a sensitivity check to confirm the person can actually taste the agent at a low concentration; someone who cannot taste it cannot be tested this way. The fit test then repeats the exercise with the respirator on, inside a test hood.
CCOHS lists the strengths and limits plainly. The strengths: it is an inexpensive test, needs no specialized equipment, and can be conducted anywhere. The limits: it is subjective because it relies on the user's senses, and it cannot be used to test full-face respirators.
How Does a Quantitative Fit Test Work?
A machine measures how much of the surrounding test aerosol gets inside the mask while the wearer performs a set of exercises such as moving their head and reading aloud. The result is a measured value rather than a yes/no answer from the wearer. CCOHS calls this the quantitative fit test (QNFT).
CCOHS lists the advantages as an accurate, objective test that can be used for any tight-fitting respirator, full-face included, and that does not depend on the individual's sense of smell or taste. The drawbacks are that it requires specialized equipment, the administrator must be trained on that equipment, the test is more expensive and it usually needs a controlled setting. For quantitative testing, the fit tester must also be able to calibrate the machine and recognize when it needs calibration.
Qualitative vs Quantitative: Which Should You Choose?
Choose qualitative for disposable and half-mask respirators when you want to test your own staff on site at low cost. Choose quantitative when the respirator is full-face, when you need a measured result, or when you would rather have a service provider do the testing. The respirator type often decides it.
| Question | Qualitative (QLFT) | Quantitative (QNFT) |
|---|---|---|
| How is the result decided? | Wearer tastes or smells the test agent: pass or fail | A machine measures leakage during exercises |
| Objective? | No, it relies on the user's senses | Yes |
| Full-face respirators? | Cannot be used | Can be used |
| N95 and half-mask? | Yes | Yes |
| Equipment | No specialized equipment; a test kit | Specialized instrument that needs calibration |
| Operator | Competent fit tester | Competent fit tester trained on the machine |
| Where it can be done | Anywhere | Usually a controlled setting |
| Relative cost | Lower | Higher |
Two practical points follow. A mixed fleet of N95s and a few full-face masks needs both methods or an outside provider for the full-face fits. And because the qualitative test is subjective, the quality of the tester matters: CCOHS says there is no specific formal training required in Canadian occupational health and safety legislation, but the tester must be competent in the method, able to run the sensitivity screening, interpret the results and document the findings. Manufacturer training on the kit is a sensible starting point.
What Does a Qualitative Fit Test Kit Include?
The 3M FT-30 carton lists a sensitivity solution, a fit test solution, two nebulizers, two sets of replacement nebulizer inserts, and a test hood and collar. ERE carries the 3M qualitative kits and the replacement solutions:
- 3M FT-10 and FT-30 qualitative fit test kits: FT-10 uses a sweet (saccharin) solution and FT-30 a bitter (Bitrex) solution. The product record states they meet the performance criteria for fit testing respirators under the OSHA respiratory protection standard and CSA Z94.4, and can be used with any particulate respirator or any gas and vapour respirator with a particulate filter. They determine the employee's taste threshold and allow the exercises to be performed in a test atmosphere. A safety data sheet is attached to the product page.
- 3M FT-31 and FT-32 bitter fit test solutions: replacement bitter solutions for the FT-30 kit, FT-31 for sensitivity and FT-32 for the fit test, so a program can keep testing without buying a whole new kit.
ERE does not currently list a quantitative fit test instrument. If your program needs one, or full-face testing, tell us and we will point you to the right route. For the full range of respiratory equipment, see the respiratory protection collection.
What Has to Be in Place Before the Test?
Three things: medical clearance to wear a respirator, a clean-shaven seal area, and the respirator and accessories the worker will actually wear on the job. CCOHS sets these out for fit testers:
- Medical surveillance: completed before using a respirator, so the user can wear one safely and do the job without risk to their health. Requirements vary by jurisdiction.
- Clean-shaven: facial hair that interferes with the seal must be removed. CSA Z94.4-18 (R2023) recommends shaving 12 to 24 hours before wearing respirators.
- Test as worn: the worker wears the respirator under the conditions the fit test is meant to cover. For example, dentures worn at work should be worn during the test.
If other protective equipment is worn with the respirator, such as eye protection, test with it on. Our safety glasses guide and PAPR guide cover the neighbouring decisions; a loose-fitting powered respirator does not rely on a face seal in the same way.
How Often Should a Respirator Fit Test Be Repeated?
CCOHS says fit testing should be repeated every two years, and sooner after changes such as an alteration to face shape, significant weight change, dental work or facial surgery that affects facial structure, or a switch to a different size or make of respirator. It should also be repeated if the respirator causes significant discomfort or if the use of other PPE changes in a way that affects the respirator.
Keep a record of every test. CCOHS recommends it include the date, the person tested and the tester, the make, model and size of respirator, whether the test was qualitative (with the agent used) or quantitative (with the technology used), the pass or fail criteria, other PPE worn, any restrictions as they relate to facial features, facial hair, dentures, eyewear or cosmetics, and the reason for any failed test. A fit test card for the worker is a common way to carry this.
Need help setting up respirator fit testing?
ERE Inc. has been Canada's environmental equipment specialist for 30+ years. Tell us your respirator types and head count and we will quote the right qualitative kit and replacement solutions.
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Frequently Asked Questions
What is the difference between a qualitative and a quantitative fit test?
A qualitative test relies on the wearer tasting or smelling a test agent and gives a pass or fail. A quantitative test uses a machine to measure how much test aerosol leaks into the mask, giving an objective result.
Can an N95 respirator be fit tested with a qualitative kit?
Yes. CCOHS lists disposable respirators such as N95s among the respirators that need a fit test, and the 3M kits are described as usable with any particulate respirator. Confirm the method your own program and jurisdiction accept.
Can you use a qualitative fit test on a full-face respirator?
No. CCOHS states that qualitative fit testing cannot be used to test full-face respirators. Use a quantitative fit test for those.
How often does a respirator need to be fit tested?
CCOHS says every two years, and again sooner after changes that affect the seal, such as significant weight change, dental work, facial surgery or switching to a different make or size of respirator.
Does a worker need to be clean-shaven for a fit test?
Yes, in the area where the respirator seals. CSA Z94.4-18 (R2023) recommends shaving 12 to 24 hours before wearing a respirator.
Who is allowed to conduct a fit test?
A competent fit tester. CCOHS notes there is no specific formal training required in Canadian occupational health and safety legislation, but the tester must know the method, run the sensitivity screening, interpret results and document them.
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- Powered Air-Purifying Respirator (PAPR): How It Works and How to Choose
- Safety Glasses: How to Read CSA Z94.3 and Choose in Canada
- Disposable Coveralls: How to Choose Between PP, Microporous and Type 5/6
Lire en français : Essai d'ajustement des respirateurs : qualitatif ou quantitatif, quelle méthode choisir au Canada?