Qualitative vs. Quantitative Respirator Fit Testing: Which Does Your Team Need?

Every worker who wears a tight-fitting respirator needs a fit test before first use and at least once a year in BC. There are two ways to do it, qualitative and quantitative, and they are not interchangeable. This guide explains both so you can pick the right one for your respirators.

The first part of this guide is general information about both methods. The last section explains what Clear Work provides.

Qualitative fit testing

A qualitative test is pass/fail and relies on the worker's own senses. The worker wears the respirator under a hood while a test agent with a distinctive taste, such as saccharin (sweet) or Bitrex (bitter), is introduced. The worker moves through a series of exercises: breathing normally and deeply, turning and nodding the head, talking and bending. If they can taste the agent, the respirator is leaking and the test fails.

Quantitative fit testing

A quantitative test uses an instrument to measure how much air leaks into the respirator. The result is a number called a fit factor: the ratio of the particle concentration outside the facepiece to the concentration inside. The higher the number, the better the seal. It doesn't depend on the worker's sense of taste, and it gives a measured record of how well each respirator fits.

Side by side

The two methods differ on four things that matter in practice.

• How the result is produced. Qualitative depends on whether the worker can taste a test agent. Quantitative uses an instrument and does not rely on the worker's senses at all.
• What you get. Qualitative gives a pass or a fail. Quantitative gives a fit factor, a number you can record and compare year over year.
• Which respirators it covers. Qualitative suits N95 and half-face respirators. Quantitative covers those as well as full-face.
• What can throw the result off. A worker with a poor sense of taste, or one who has just eaten, drunk or smoked, can affect a qualitative result. Quantitative removes that variable.

Which method does your respirator need?

The method depends on the respirator. Fit testing in BC follows CSA Standard Z94.4.

• N95 and other disposable respirators: qualitative testing is commonly used.
• Half-face reusable respirators: qualitative testing is commonly used.
• Full-face respirators: according to the Canadian Centre for Occupational Health and Safety (CCOHS), qualitative testing cannot be used for full-face respirators under CSA Z94.4. They need a quantitative test.

Check your written respiratory protection program and the respirator manufacturer's instructions to confirm which method applies to each model your workers use.

What counts as a pass

Qualitative testing has no number attached to it. The worker either detects the test agent or they do not.

Quantitative testing produces a fit factor, and there is a minimum that fit factor has to reach. The standard pass levels are a fit factor of at least 100 for half facepiece and filtering facepiece respirators, and at least 500 for full facepiece respirators. A worker who does not reach the threshold for their respirator has not passed, whatever the number says.

Because the result is a measurement rather than a yes or no, quantitative testing also shows how much margin each worker has. Someone who scrapes past at 110 on a half-face is in a different position from someone who records 900 on the same mask, even though both are recorded as a pass.

What happens if a worker fails

A failed fit test is not a problem with the worker. It is a problem with the match between that face and that particular respirator. The usual next step is to try a different size, and then a different model. Most people who fail on their first respirator pass on another.

Two things cause most avoidable failures. The first is facial hair along the seal line: nothing can come between the respirator and the skin where it seals. The second is testing on a respirator the worker does not actually wear. Workers should be tested on the exact make, model and size they use on the job, along with anything they normally wear with it, such as safety glasses or a hard hat.

What Clear Work provides

Clear Work provides both methods on site. Qualitative fit testing for N95 respirators and suitable half-face respirators, from 5 people per visit. Quantitative fit testing — which covers full-face respirators and tight-fitting PAPR facepieces as well as N95 and half-face — for larger groups.

If your crew uses full-face respirators, quantitative is the method you need, and we can test them during the same visit as the rest of your team. Smaller groups can be accommodated for an additional fee, so if only a handful of your workers use full-face respirators, tell us your numbers and we will quote it rather than turn you away.

Each test typically takes 10 to 15 minutes, and records go into your client portal.

Read our guide to WorkSafeBC's fit testing requirements, learn about our on-site fit testing or request a quote.

This guide is general information, not legal advice. Always check the current OHS Regulation and CSA Z94.4 for the exact requirements that apply to your workplace.